Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Git-backup - Backup set of Git repositories & just files; efficiently. This program backups files and set of bare Git repositories into one Git repository. Files are copied to blobs and then added to tree under certain place, and for Git repositories, all reachable objects are pulled in with maintaining index which remembers reference -> sha1 for every pulled repositories. After objects from backuped Git repositories are pulled in, we create new commit which references tree with changed backup index and files, and also has all head objects from pulled-in repositories in its parents(*). This way backup has history and all pulled objects become reachable from single head commit in backup repository. In particular that means that the whole state of backup can be described with only single sha1, and that backup repository itself could be synchronized via standard git pull/push, be repacked, etc. Restoration process is the opposite - from a particular backup state, files are extracted at a proper place, and for Git repositories a pack with all objects reachable from that repository heads is prepared and extracted from backup repository object database. This approach allows to leverage Git's good ability for object contents deduplication and packing, especially for cases when there are many hosted repositories which are forks of each other with relatively minor changes in between each other and over time, and mostly common base. In author experience the size of backup is dramatically smaller compared to straightforward "let's tar it all" approach. Data for all backuped files and repositories can be accessed if one has access to backup repository, so either they all should be in the same security domain, or extra care has to be taken to protect access to backup repository. File permissions are not managed with strict details due to inherent nature of Git. This aspect can be improved with e.g. etckeeper-like (http://etckeeper.branchable.com/) approach if needed. Please see README.rst with user-level overview on how to use git-backup. NOTE the idea of pulling all refs together is similar to git-namespaces (*) Tag objects are handled specially - because in a lot of places Git insists and
Package v8 provides a Go API for the the V8 javascript engine. This allows running javascript within a go executable. The bindings have been tested with v8 builds between 5.1.281.16 through 6.7.77. V8 provides two main concepts for managing javascript state: Isolates and Contexts. An isolate represents a single-threaded javascript engine that can manage one or more contexts. A context is a sandboxed javascript execution environment. Thus, if you have one isolate, you could safely execute independent code in many different contexts created in that isolate. The code in the various contexts would not interfere with each other, however no more than one context would ever be executing at a given time. If you have multiple isolates, they may be executing in separate threads simultaneously. This work is based off of several existing libraries:
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package saml contains a partial implementation of the SAML standard in golang. SAML is a standard for identity federation, i.e. either allowing a third party to authenticate your users or allowing third parties to rely on us to authenticate their users. In SAML parlance an Identity Provider (IDP) is a service that knows how to authenticate users. A Service Provider (SP) is a service that delegates authentication to an IDP. If you are building a service where users log in with someone else's credentials, then you are a Service Provider. This package supports implementing both service providers and identity providers. The core package contains the implementation of SAML. The package samlsp provides helper middleware suitable for use in Service Provider applications. The package samlidp provides a rudimentary IDP service that is useful for testing or as a starting point for other integrations. Version 0.4.0 introduces a few breaking changes to the _samlsp_ package in order to make the package more extensible, and to clean up the interfaces a bit. The default behavior remains the same, but you can now provide interface implementations of _RequestTracker_ (which tracks pending requests), _Session_ (which handles maintaining a session) and _OnError_ which handles reporting errors. Public fields of _samlsp.Middleware_ have changed, so some usages may require adjustment. See [issue 231](https://github.com/crewjam/saml/issues/231) for details. The option to provide an IDP metadata URL has been deprecated. Instead, we recommend that you use the `FetchMetadata()` function, or fetch the metadata yourself and use the new `ParseMetadata()` function, and pass the metadata in _samlsp.Options.IDPMetadata_. Similarly, the _HTTPClient_ field is now deprecated because it was only used for fetching metdata, which is no longer directly implemented. The fields that manage how cookies are set are deprecated as well. To customize how cookies are managed, provide custom implementation of _RequestTracker_ and/or _Session_, perhaps by extending the default implementations. The deprecated fields have not been removed from the Options structure, but will be in future. In particular we have deprecated the following fields in _samlsp.Options_: - `Logger` - This was used to emit errors while validating, which is an anti-pattern. - `IDPMetadataURL` - Instead use `FetchMetadata()` - `HTTPClient` - Instead pass httpClient to FetchMetadata - `CookieMaxAge` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieName` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieDomain` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieDomain` - Instead assign a custom CookieRequestTracker or CookieSessionProvider Let us assume we have a simple web application to protect. We'll modify this application so it uses SAML to authenticate users. ```golang package main import ( ) ``` Each service provider must have an self-signed X.509 key pair established. You can generate your own with something like this: We will use `samlsp.Middleware` to wrap the endpoint we want to protect. Middleware provides both an `http.Handler` to serve the SAML specific URLs and a set of wrappers to require the user to be logged in. We also provide the URL where the service provider can fetch the metadata from the IDP at startup. In our case, we'll use [samltest.id](https://samltest.id/), an identity provider designed for testing. ```golang package main import ( ) ``` Next we'll have to register our service provider with the identity provider to establish trust from the service provider to the IDP. For [samltest.id](https://samltest.id/), you can do something like: Navigate to https://samltest.id/upload.php and upload the file you fetched. Now you should be able to authenticate. The flow should look like this: 1. You browse to `localhost:8000/hello` 1. The middleware redirects you to `https://samltest.id/idp/profile/SAML2/Redirect/SSO` 1. samltest.id prompts you for a username and password. 1. samltest.id returns you an HTML document which contains an HTML form setup to POST to `localhost:8000/saml/acs`. The form is automatically submitted if you have javascript enabled. 1. The local service validates the response, issues a session cookie, and redirects you to the original URL, `localhost:8000/hello`. 1. This time when `localhost:8000/hello` is requested there is a valid session and so the main content is served. Please see `example/idp/` for a substantially complete example of how to use the library and helpers to be an identity provider. The SAML standard is huge and complex with many dark corners and strange, unused features. This package implements the most commonly used subset of these features required to provide a single sign on experience. The package supports at least the subset of SAML known as [interoperable SAML](http://saml2int.org). This package supports the Web SSO profile. Message flows from the service provider to the IDP are supported using the HTTP Redirect binding and the HTTP POST binding. Message flows from the IDP to the service provider are supported via the HTTP POST binding. The package can produce signed SAML assertions, and can validate both signed and encrypted SAML assertions. It does not support signed or encrypted requests. The _RelayState_ parameter allows you to pass user state information across the authentication flow. The most common use for this is to allow a user to request a deep link into your site, be redirected through the SAML login flow, and upon successful completion, be directed to the originally requested link, rather than the root. Unfortunately, _RelayState_ is less useful than it could be. Firstly, it is not authenticated, so anything you supply must be signed to avoid XSS or CSRF. Secondly, it is limited to 80 bytes in length, which precludes signing. (See section 3.6.3.1 of SAMLProfiles.) The SAML specification is a collection of PDFs (sadly): - [SAMLCore](http://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf) defines data types. - [SAMLBindings](http://docs.oasis-open.org/security/saml/v2.0/saml-bindings-2.0-os.pdf) defines the details of the HTTP requests in play. - [SAMLProfiles](http://docs.oasis-open.org/security/saml/v2.0/saml-profiles-2.0-os.pdf) describes data flows. - [SAMLConformance](http://docs.oasis-open.org/security/saml/v2.0/saml-conformance-2.0-os.pdf) includes a support matrix for various parts of the protocol. [SAMLtest](https://samltest.id/) is a testing ground for SAML service and identity providers. Please do not report security issues in the issue tracker. Rather, please contact me directly at ross@kndr.org ([PGP Key `78B6038B3B9DFB88`](https://keybase.io/crewjam)).
This package is the root package of the govmomi library. The library is structured as follows: The minimal usable functionality is available through the vim25 package. It contains subpackages that contain generated types, managed objects, and all available methods. The vim25 package is entirely independent of the other packages in the govmomi tree -- it has no dependencies on its peers. The vim25 package itself contains a client structure that is passed around throughout the entire library. It abstracts a session and its immutable state. See the vim25 package for more information. The session package contains an abstraction for the session manager that allows a user to login and logout. It also provides access to the current session (i.e. to determine if the user is in fact logged in) The object package contains wrappers for a selection of managed objects. The constructors of these objects all take a *vim25.Client, which they pass along to derived objects, if applicable. The govc package contains the govc CLI. The code in this tree is not intended to be used as a library. Any functionality that govc contains that _could_ be used as a library function but isn't, _should_ live in a root level package. Other packages, such as "event", "guest", or "license", provide wrappers for the respective subsystems. They are typically not needed in normal workflows so are kept outside the object package.
Package ordu provides a minimal framework for writing CLIs. It aims to have an extremely small API by relying on command implementations to manage their own internal state and initialization.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package skipper provides an HTTP routing library with flexible configuration as well as a runtime update of the routing rules. Skipper works as an HTTP reverse proxy that is responsible for mapping incoming requests to multiple HTTP backend services, based on routes that are selected by the request attributes. At the same time, both the requests and the responses can be augmented by a filter chain that is specifically defined for each route. Skipper can load and update the route definitions from multiple data sources without being restarted. It provides a default executable command with a few built-in filters, however, its primary use case is to be extended with custom filters, predicates or data sources. For futher information read 'Extending Skipper'. Skipper took the core design and inspiration from Vulcand: https://github.com/mailgun/vulcand. Skipper is 'go get' compatible. If needed, create a 'go workspace' first: Get the Skipper packages: Create a file with a route: Optionally, verify the syntax of the file: Start Skipper and make an HTTP request: The core of Skipper's request processing is implemented by a reverse proxy in the 'proxy' package. The proxy receives the incoming request, forwards it to the routing engine in order to receive the most specific matching route. When a route matches, the request is forwarded to all filters defined by it. The filters can modify the request or execute any kind of program logic. Once the request has been processed by all the filters, it is forwarded to the backend endpoint of the route. The response from the backend goes once again through all the filters in reverse order. Finally, it is mapped as the response of the original incoming request. Besides the default proxying mechanism, it is possible to define routes without a real network backend endpoint. One of these cases is called a 'shunt' backend, in which case one of the filters needs to handle the request providing its own response (e.g. the 'static' filter). Actually, filters themselves can instruct the request flow to shunt by calling the Serve(*http.Response) method of the filter context. Another case of a route without a network backend is the 'loopback'. A loopback route can be used to match a request, modified by filters, against the lookup tree with different conditions and then execute a different route. One example scenario can be to use a single route as an entry point to execute some calculation to get an A/B testing decision and then matching the updated request metadata for the actual destination route. This way the calculation can be executed for only those requests that don't contain information about a previously calculated decision. For further details, see the 'proxy' and 'filters' package documentation. Finding a request's route happens by matching the request attributes to the conditions in the route's definitions. Such definitions may have the following conditions: - method - path (optionally with wildcards) - path regular expressions - host regular expressions - headers - header regular expressions It is also possible to create custom predicates with any other matching criteria. The relation between the conditions in a route definition is 'and', meaning, that a request must fulfill each condition to match a route. For further details, see the 'routing' package documentation. Filters are applied in order of definition to the request and in reverse order to the response. They are used to modify request and response attributes, such as headers, or execute background tasks, like logging. Some filters may handle the requests without proxying them to service backends. Filters, depending on their implementation, may accept/require parameters, that are set specifically to the route. For further details, see the 'filters' package documentation. Each route has one of the following backends: HTTP endpoint, shunt or loopback. Backend endpoints can be any HTTP service. They are specified by their network address, including the protocol scheme, the domain name or the IP address, and optionally the port number: e.g. "https://www.example.org:4242". (The path and query are sent from the original request, or set by filters.) A shunt route means that Skipper handles the request alone and doesn't make requests to a backend service. In this case, it is the responsibility of one of the filters to generate the response. A loopback route executes the routing mechanism on current state of the request from the start, including the route lookup. This way it serves as a form of an internal redirect. Route definitions consist of the following: - request matching conditions (predicates) - filter chain (optional) - backend (either an HTTP endpoint or a shunt) The eskip package implements the in-memory and text representations of route definitions, including a parser. (Note to contributors: in order to stay compatible with 'go get', the generated part of the parser is stored in the repository. When changing the grammar, 'go generate' needs to be executed explicitly to update the parser.) For further details, see the 'eskip' package documentation Skipper's route definitions of Skipper are loaded from one or more data sources. It can receive incremental updates from those data sources at runtime. It provides three different data clients: - Innkeeper: the Innkeeper service implements a storage for large sets of Skipper routes, with an HTTP+JSON API, OAuth2 authentication and role management. See the 'innkeeper' package and https://github.com/zalando/innkeeper. - etcd: Skipper can load routes and receive updates from etcd clusters (https://github.com/coreos/etcd). See the 'etcd' package. - static file: package eskipfile implements a simple data client, which can load route definitions from a static file in eskip format. Currently, it loads the routes on startup. It doesn't support runtime updates. Skipper can use additional data sources, provided by extensions. Sources must implement the DataClient interface in the routing package. Skipper can be started with the default executable command 'skipper', or as a library built into an application. The easiest way to start Skipper as a library is to execute the 'Run' function of the current, root package. Each option accepted by the 'Run' function is wired in the default executable as well, as a command line flag. E.g. EtcdUrls becomes -etcd-urls as a comma separated list. For command line help, enter: An additional utility, eskip, can be used to verify, print, update and delete routes from/to files or etcd (Innkeeper on the roadmap). See the cmd/eskip command package, and/or enter in the command line: Skipper doesn't use dynamically loaded plugins, however, it can be used as a library, and it can be extended with custom predicates, filters and/or custom data sources. To create a custom predicate, one needs to implement the PredicateSpec interface in the routing package. Instances of the PredicateSpec are used internally by the routing package to create the actual Predicate objects as referenced in eskip routes, with concrete arguments. Example, randompredicate.go: In the above example, a custom predicate is created, that can be referenced in eskip definitions with the name 'Random': To create a custom filter we need to implement the Spec interface of the filters package. 'Spec' is the specification of a filter, and it is used to create concrete filter instances, while the raw route definitions are processed. Example, hellofilter.go: The above example creates a filter specification, and in the routes where they are included, the filter instances will set the 'X-Hello' header for each and every response. The name of the filter is 'hello', and in a route definition it is referenced as: The easiest way to create a custom Skipper variant is to implement the required filters (as in the example above) by importing the Skipper package, and starting it with the 'Run' command. Example, hello.go: A file containing the routes, routes.eskip: Start the custom router: The 'Run' function in the root Skipper package starts its own listener but it doesn't provide the best composability. The proxy package, however, provides a standard http.Handler, so it is possible to use it in a more complex solution as a building block for routing. Skipper provides detailed logging of failures, and access logs in Apache log format. Skipper also collects detailed performance metrics, and exposes them on a separate listener endpoint for pulling snapshots. For details, see the 'logging' and 'metrics' packages documentation. The router's performance depends on the environment and on the used filters. Under ideal circumstances, and without filters, the biggest time factor is the route lookup. Skipper is able to scale to thousands of routes with logarithmic performance degradation. However, this comes at the cost of increased memory consumption, due to storing the whole lookup tree in a single structure. Benchmarks for the tree lookup can be run by: In case more aggressive scale is needed, it is possible to setup Skipper in a cascade model, with multiple Skipper instances for specific route segments.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. However, support is provided to translate UTF-8 runes to code page encodings. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Additionally, he augmented the basic HTML functionality with aligned text. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retreived with the output call where it can be handled by the application.
Package gophercloud provides a multi-vendor interface to OpenStack-compatible clouds. The library has a three-level hierarchy: providers, services, and resources. Provider structs represent the cloud providers that offer and manage a collection of services. You will generally want to create one Provider client per OpenStack cloud. Use your OpenStack credentials to create a Provider client. The IdentityEndpoint is typically refered to as "auth_url" or "OS_AUTH_URL" in information provided by the cloud operator. Additionally, the cloud may refer to TenantID or TenantName as project_id and project_name. Credentials are specified like so: You can authenticate with a token by doing: You may also use the openstack.AuthOptionsFromEnv() helper function. This function reads in standard environment variables frequently found in an OpenStack `openrc` file. Again note that Gophercloud currently uses "tenant" instead of "project". Service structs are specific to a provider and handle all of the logic and operations for a particular OpenStack service. Examples of services include: Compute, Object Storage, Block Storage. In order to define one, you need to pass in the parent provider, like so: Resource structs are the domain models that services make use of in order to work with and represent the state of API resources: Intermediate Result structs are returned for API operations, which allow generic access to the HTTP headers, response body, and any errors associated with the network transaction. To turn a result into a usable resource struct, you must call the Extract method which is chained to the response, or an Extract function from an applicable extension: All requests that enumerate a collection return a Pager struct that is used to iterate through the results one page at a time. Use the EachPage method on that Pager to handle each successive Page in a closure, then use the appropriate extraction method from that request's package to interpret that Page as a slice of results: If you want to obtain the entire collection of pages without doing any intermediary processing on each page, you can use the AllPages method: This top-level package contains utility functions and data types that are used throughout the provider and service packages. Of particular note for end users are the AuthOptions and EndpointOpts structs. An example retry backoff function, which respects the 429 HTTP response code and a "Retry-After" header:
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package autorest implements an HTTP request pipeline suitable for use across multiple go-routines and provides the shared routines relied on by AutoRest (see https://github.com/Azure/autorest/) generated Go code. The package breaks sending and responding to HTTP requests into three phases: Preparing, Sending, and Responding. A typical pattern is: Each phase relies on decorators to modify and / or manage processing. Decorators may first modify and then pass the data along, pass the data first and then modify the result, or wrap themselves around passing the data (such as a logger might do). Decorators run in the order provided. For example, the following: will set the URL to: Preparers and Responders may be shared and re-used (assuming the underlying decorators support sharing and re-use). Performant use is obtained by creating one or more Preparers and Responders shared among multiple go-routines, and a single Sender shared among multiple sending go-routines, all bound together by means of input / output channels. Decorators hold their passed state within a closure (such as the path components in the example above). Be careful to share Preparers and Responders only in a context where such held state applies. For example, it may not make sense to share a Preparer that applies a query string from a fixed set of values. Similarly, sharing a Responder that reads the response body into a passed struct (e.g., ByUnmarshallingJson) is likely incorrect. Lastly, the Swagger specification (https://swagger.io) that drives AutoRest (https://github.com/Azure/autorest/) precisely defines two date forms: date and date-time. The github.com/Azure/go-autorest/autorest/date package provides time.Time derivations to ensure correct parsing and formatting. Errors raised by autorest objects and methods will conform to the autorest.Error interface. See the included examples for more detail. For details on the suggested use of this package by generated clients, see the Client described below.
Package goa provides the runtime support for goa microservices. goa service development begins with writing the *design* of a service. The design is described using the goa language implemented by the github.com/goadesign/goa/design/apidsl package. The `goagen` tool consumes the metadata produced from executing the design language to generate service specific code that glues the underlying HTTP server with action specific code and data structures. The goa package contains supporting functionality for the generated code including basic request and response state management through the RequestData and ResponseData structs, error handling via error classes, middleware support via the Middleware data structure as well as decoding and encoding algorithms. The RequestData and ResponseData structs provides access to the request and response state. goa request handlers also accept a context.Context interface as first parameter so that deadlines and cancelation signals may easily be implemented. The request state exposes the underlying http.Request object as well as the deserialized payload (request body) and parameters (both path and querystring parameters). Generated action specific contexts wrap the context.Context, ResponseData and RequestData data structures. They expose properly typed fields that correspond to the request parameters and body data structure descriptions appearing in the design. The response state exposes the response status and body length as well as the underlying ResponseWriter. Action contexts provide action specific helper methods that write the responses as described in the design optionally taking an instance of the media type for responses that contain a body. Here is an example showing an "update" action corresponding to following design (extract): The action signature generated by goagen is: where UpdateBottleContext is: and implements: The definitions of the Bottle and UpdateBottlePayload data structures are ommitted for brievity. There is one controller interface generated per resource defined via the design language. The interface exposes the controller actions. User code must provide data structures that implement these interfaces when mounting a controller onto a service. The controller data structure should include an anonymous field of type *goa.Controller which takes care of implementing the middleware handling. A goa middleware is a function that takes and returns a Handler. A Handler is a the low level function which handles incoming HTTP requests. goagen generates the handlers code so each handler creates the action specific context and calls the controller action with it. Middleware can be added to a goa service or a specific controller using the corresponding Use methods. goa comes with a few stock middleware that handle common needs such as logging, panic recovery or using the RequestID header to trace requests across multiple services. The controller action methods generated by goagen such as the Update method of the BottleController interface shown above all return an error value. goa defines an Error struct that action implementations can use to describe the content of the corresponding HTTP response. Errors can be created using error classes which are functions created via NewErrorClass. The ErrorHandler middleware maps errors to HTTP responses. Errors that are instances of the Error struct are mapped using the struct fields while other types of errors return responses with status code 500 and the error message in the body. The goa design language documented in the dsl package makes it possible to attach validations to data structure definitions. One specific type of validation consists of defining the format that a data structure string field must follow. Example of formats include email, data time, hostnames etc. The ValidateFormat function provides the implementation for the format validation invoked from the code generated by goagen. The goa design language makes it possible to specify the encodings supported by the API both as input (Consumes) and output (Produces). goagen uses that information to registed the corresponding packages with the service encoders and decoders via their Register methods. The service exposes the DecodeRequest and EncodeResponse that implement a simple content type negotiation algorithm for picking the right encoder for the "Content-Type" (decoder) or "Accept" (encoder) request header. Package goa standardizes on structured error responses: a request that fails because of an invalid input or an unexpected condition produces a response that contains a structured error. The error data structures returned to clients contains five fields: an ID, a code, a status, a detail and metadata. The ID is unique for the occurrence of the error, it helps correlate the content of the response with the content of the service logs. The code defines the class of error (e.g. "invalid_parameter_type") and the status the corresponding HTTP status (e.g. 400). The detail contains a message specific to the error occurrence. The metadata contains key/value pairs that provide contextual information (name of parameters, value of invalid parameter etc.). Instances of Error can be created via Error Class functions. See http://goa.design/implement/error_handling.html All instance of errors created via a error class implement the ServiceError interface. This interface is leveraged by the error handler middleware to produce the error responses. The code generated by goagen calls the helper functions exposed in this file when it encounters invalid data (wrong type, validation errors etc.) such as InvalidParamTypeError, InvalidAttributeTypeError etc. These methods return errors that get merged with any previously encountered error via the Error Merge method. The helper functions are error classes stored in global variable. This means your code can override their values to produce arbitrary error responses. goa includes an error handler middleware that takes care of mapping back any error returned by previously called middleware or action handler into HTTP responses. If the error was created via an error class then the corresponding content including the HTTP status is used otherwise an internal error is returned. Errors that bubble up all the way to the top (i.e. not handled by the error middleware) also generate an internal error response.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package saml contains a partial implementation of the SAML standard in golang. SAML is a standard for identity federation, i.e. either allowing a third party to authenticate your users or allowing third parties to rely on us to authenticate their users. In SAML parlance an Identity Provider (IDP) is a service that knows how to authenticate users. A Service Provider (SP) is a service that delegates authentication to an IDP. If you are building a service where users log in with someone else's credentials, then you are a Service Provider. This package supports implementing both service providers and identity providers. The core package contains the implementation of SAML. The package samlsp provides helper middleware suitable for use in Service Provider applications. The package samlidp provides a rudimentary IDP service that is useful for testing or as a starting point for other integrations. Version 0.4.0 introduces a few breaking changes to the _samlsp_ package in order to make the package more extensible, and to clean up the interfaces a bit. The default behavior remains the same, but you can now provide interface implementations of _RequestTracker_ (which tracks pending requests), _Session_ (which handles maintaining a session) and _OnError_ which handles reporting errors. Public fields of _samlsp.Middleware_ have changed, so some usages may require adjustment. See [issue 231](https://github.com/crewjam/saml/issues/231) for details. The option to provide an IDP metadata URL has been deprecated. Instead, we recommend that you use the `FetchMetadata()` function, or fetch the metadata yourself and use the new `ParseMetadata()` function, and pass the metadata in _samlsp.Options.IDPMetadata_. Similarly, the _HTTPClient_ field is now deprecated because it was only used for fetching metdata, which is no longer directly implemented. The fields that manage how cookies are set are deprecated as well. To customize how cookies are managed, provide custom implementation of _RequestTracker_ and/or _Session_, perhaps by extending the default implementations. The deprecated fields have not been removed from the Options structure, but will be in future. In particular we have deprecated the following fields in _samlsp.Options_: - `Logger` - This was used to emit errors while validating, which is an anti-pattern. - `IDPMetadataURL` - Instead use `FetchMetadata()` - `HTTPClient` - Instead pass httpClient to FetchMetadata - `CookieMaxAge` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieName` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieDomain` - Instead assign a custom CookieRequestTracker or CookieSessionProvider - `CookieDomain` - Instead assign a custom CookieRequestTracker or CookieSessionProvider Let us assume we have a simple web application to protect. We'll modify this application so it uses SAML to authenticate users. ```golang package main import ( ) ``` Each service provider must have an self-signed X.509 key pair established. You can generate your own with something like this: We will use `samlsp.Middleware` to wrap the endpoint we want to protect. Middleware provides both an `http.Handler` to serve the SAML specific URLs and a set of wrappers to require the user to be logged in. We also provide the URL where the service provider can fetch the metadata from the IDP at startup. In our case, we'll use [samltest.id](https://samltest.id/), an identity provider designed for testing. ```golang package main import ( ) ``` Next we'll have to register our service provider with the identity provider to establish trust from the service provider to the IDP. For [samltest.id](https://samltest.id/), you can do something like: Navigate to https://samltest.id/upload.php and upload the file you fetched. Now you should be able to authenticate. The flow should look like this: 1. You browse to `localhost:8000/hello` 1. The middleware redirects you to `https://samltest.id/idp/profile/SAML2/Redirect/SSO` 1. samltest.id prompts you for a username and password. 1. samltest.id returns you an HTML document which contains an HTML form setup to POST to `localhost:8000/saml/acs`. The form is automatically submitted if you have javascript enabled. 1. The local service validates the response, issues a session cookie, and redirects you to the original URL, `localhost:8000/hello`. 1. This time when `localhost:8000/hello` is requested there is a valid session and so the main content is served. Please see `example/idp/` for a substantially complete example of how to use the library and helpers to be an identity provider. The SAML standard is huge and complex with many dark corners and strange, unused features. This package implements the most commonly used subset of these features required to provide a single sign on experience. The package supports at least the subset of SAML known as [interoperable SAML](http://saml2int.org). This package supports the Web SSO profile. Message flows from the service provider to the IDP are supported using the HTTP Redirect binding and the HTTP POST binding. Message flows from the IDP to the service provider are supported via the HTTP POST binding. The package can produce signed SAML assertions, and can validate both signed and encrypted SAML assertions. It does not support signed or encrypted requests. The _RelayState_ parameter allows you to pass user state information across the authentication flow. The most common use for this is to allow a user to request a deep link into your site, be redirected through the SAML login flow, and upon successful completion, be directed to the originally requested link, rather than the root. Unfortunately, _RelayState_ is less useful than it could be. Firstly, it is not authenticated, so anything you supply must be signed to avoid XSS or CSRF. Secondly, it is limited to 80 bytes in length, which precludes signing. (See section 3.6.3.1 of SAMLProfiles.) The SAML specification is a collection of PDFs (sadly): - [SAMLCore](http://docs.oasis-open.org/security/saml/v2.0/saml-core-2.0-os.pdf) defines data types. - [SAMLBindings](http://docs.oasis-open.org/security/saml/v2.0/saml-bindings-2.0-os.pdf) defines the details of the HTTP requests in play. - [SAMLProfiles](http://docs.oasis-open.org/security/saml/v2.0/saml-profiles-2.0-os.pdf) describes data flows. - [SAMLConformance](http://docs.oasis-open.org/security/saml/v2.0/saml-conformance-2.0-os.pdf) includes a support matrix for various parts of the protocol. [SAMLtest](https://samltest.id/) is a testing ground for SAML service and identity providers. Please do not report security issues in the issue tracker. Rather, please contact me directly at ross@kndr.org ([PGP Key `78B6038B3B9DFB88`](https://keybase.io/crewjam)).
Package peer provides a common base for creating and managing Decred network peers. This package builds upon the wire package, which provides the fundamental primitives necessary to speak the Decred wire protocol, in order to simplify the process of creating fully functional peers. In essence, it provides a common base for creating concurrent safe fully validating nodes, Simplified Payment Verification (SPV) nodes, proxies, etc. A quick overview of the major features peer provides are as follows: All peer configuration is handled with the Config struct. This allows the caller to specify things such as the user agent name and version, the decred network to use, which services it supports, and callbacks to invoke when decred messages are received. See the documentation for each field of the Config struct for more details. A peer can either be inbound or outbound. The caller is responsible for establishing the connection to remote peers and listening for incoming peers. This provides high flexibility for things such as connecting via proxies, acting as a proxy, creating bridge peers, choosing whether to listen for inbound peers, etc. NewOutboundPeer and NewInboundPeer functions must be followed by calling Connect with a net.Conn instance to the peer. This will start all async I/O goroutines and initiate the protocol negotiation process. Once finished with the peer call Disconnect to disconnect from the peer and clean up all resources. WaitForDisconnect can be used to block until peer disconnection and resource cleanup has completed. In order to do anything useful with a peer, it is necessary to react to decred messages. This is accomplished by creating an instance of the MessageListeners struct with the callbacks to be invoke specified and setting the Listeners field of the Config struct specified when creating a peer to it. For convenience, a callback hook for all of the currently supported decred messages is exposed which receives the peer instance and the concrete message type. In addition, a hook for OnRead is provided so even custom messages types for which this package does not directly provide a hook, as long as they implement the wire.Message interface, can be used. Finally, the OnWrite hook is provided, which in conjunction with OnRead, can be used to track server-wide byte counts. It is often useful to use closures which encapsulate state when specifying the callback handlers. This provides a clean method for accessing that state when callbacks are invoked. The QueueMessage function provides the fundamental means to send messages to the remote peer. As the name implies, this employs a non-blocking queue. A done channel which will be notified when the message is actually sent can optionally be specified. There are certain message types which are better sent using other functions which provide additional functionality. Of special interest are inventory messages. Rather than manually sending MsgInv messages via Queuemessage, the inventory vectors should be queued using the QueueInventory function. It employs batching and trickling along with intelligent known remote peer inventory detection and avoidance through the use of a most-recently used algorithm. In addition to the bare QueueMessage function previously described, the PushAddrMsg, PushGetBlocksMsg, PushGetHeadersMsg, and PushRejectMsg functions are provided as a convenience. While it is of course possible to create and send these message manually via QueueMessage, these helper functions provided additional useful functionality that is typically desired. For example, the PushAddrMsg function automatically limits the addresses to the maximum number allowed by the message and randomizes the chosen addresses when there are too many. This allows the caller to simply provide a slice of known addresses, such as that returned by the addrmgr package, without having to worry about the details. Next, the PushGetBlocksMsg and PushGetHeadersMsg functions will construct proper messages using a block locator and ignore back to back duplicate requests. Finally, the PushRejectMsg function can be used to easily create and send an appropriate reject message based on the provided parameters as well as optionally provides a flag to cause it to block until the message is actually sent. A snapshot of the current peer statistics can be obtained with the StatsSnapshot function. This includes statistics such as the total number of bytes read and written, the remote address, user agent, and negotiated protocol version. This package provides extensive logging capabilities through the UseLogger function which allows a btclog.Logger to be specified. For example, logging at the debug level provides summaries of every message sent and received, and logging at the trace level provides full dumps of parsed messages as well as the raw message bytes using a format similar to hexdump -C. This package supports all improvement proposals supported by the wire package. (https://godoc.org/github.com/decred/dcrd/wire#hdr-Bitcoin_Improvement_Proposals) This example demonstrates the basic process for initializing and creating an outbound peer. Peers negotiate by exchanging version and verack messages. For demonstration, a simple handler for version message is attached to the peer.
Package goa provides the runtime support for goa microservices. goa service development begins with writing the *design* of a service. The design is described using the goa language implemented by the github.com/goadesign/goa/design/apidsl package. The `goagen` tool consumes the metadata produced from executing the design language to generate service specific code that glues the underlying HTTP server with action specific code and data structures. The goa package contains supporting functionality for the generated code including basic request and response state management through the RequestData and ResponseData structs, error handling via error classes, middleware support via the Middleware data structure as well as decoding and encoding algorithms. The RequestData and ResponseData structs provides access to the request and response state. goa request handlers also accept a golang.org/x/net/Context interface as first parameter so that deadlines and cancelation signals may easily be implemented. The request state exposes the underlying http.Request object as well as the deserialized payload (request body) and parameters (both path and querystring parameters). Generated action specific contexts wrap the context.Context, ResponseData and RequestData data structures. They expose properly typed fields that correspond to the request parameters and body data structure descriptions appearing in the design. The response state exposes the response status and body length as well as the underlying ResponseWriter. Action contexts provide action specific helper methods that write the responses as described in the design optionally taking an instance of the media type for responses that contain a body. Here is an example showing an "update" action corresponding to following design (extract): The action signature generated by goagen is: where UpdateBottleContext is: and implements: The definitions of the Bottle and UpdateBottlePayload data structures are ommitted for brievity. There is one controller interface generated per resource defined via the design language. The interface exposes the controller actions. User code must provide data structures that implement these interfaces when mounting a controller onto a service. The controller data structure should include an anonymous field of type *goa.Controller which takes care of implementing the middleware handling. A goa middleware is a function that takes and returns a Handler. A Handler is a the low level function which handles incoming HTTP requests. goagen generates the handlers code so each handler creates the action specific context and calls the controller action with it. Middleware can be added to a goa service or a specific controller using the corresponding Use methods. goa comes with a few stock middleware that handle common needs such as logging, panic recovery or using the RequestID header to trace requests across multiple services. The controller action methods generated by goagen such as the Update method of the BottleController interface shown above all return an error value. goa defines an Error struct that action implementations can use to describe the content of the corresponding HTTP response. Errors can be created using error classes which are functions created via NewErrorClass. The ErrorHandler middleware maps errors to HTTP responses. Errors that are instances of the Error struct are mapped using the struct fields while other types of errors return responses with status code 500 and the error message in the body. The goa design language documented in the dsl package makes it possible to attach validations to data structure definitions. One specific type of validation consists of defining the format that a data structure string field must follow. Example of formats include email, data time, hostnames etc. The ValidateFormat function provides the implementation for the format validation invoked from the code generated by goagen. The goa design language makes it possible to specify the encodings supported by the API both as input (Consumes) and output (Produces). goagen uses that information to registed the corresponding packages with the service encoders and decoders via their Register methods. The service exposes the DecodeRequest and EncodeResponse that implement a simple content type negotiation algorithm for picking the right encoder for the "Content-Type" (decoder) or "Accept" (encoder) request header. Package goa standardizes on structured error responses: a request that fails because of an invalid input or an unexpected condition produces a response that contains a structured error. The error data structures returned to clients contains five fields: an ID, a code, a status, a detail and metadata. The ID is unique for the occurrence of the error, it helps correlate the content of the response with the content of the service logs. The code defines the class of error (e.g. "invalid_parameter_type") and the status the corresponding HTTP status (e.g. 400). The detail contains a message specific to the error occurrence. The metadata contains key/value pairs that provide contextual information (name of parameters, value of invalid parameter etc.). Instances of Error can be created via Error Class functions. See http://goa.design/implement/error_handling.html All instance of errors created via a error class implement the ServiceError interface. This interface is leveraged by the error handler middleware to produce the error responses. The code generated by goagen calls the helper functions exposed in this file when it encounters invalid data (wrong type, validation errors etc.) such as InvalidParamTypeError, InvalidAttributeTypeError etc. These methods return errors that get merged with any previously encountered error via the Error Merge method. The helper functions are error classes stored in global variable. This means your code can override their values to produce arbitrary error responses. goa includes an error handler middleware that takes care of mapping back any error returned by previously called middleware or action handler into HTTP responses. If the error was created via an error class then the corresponding content including the HTTP status is used otherwise an internal error is returned. Errors that bubble up all the way to the top (i.e. not handled by the error middleware) also generate an internal error response.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Pact Go enables consumer driven contract testing, providing a mock service and DSL for the consumer project, and interaction playback and verification for the service provider project. Consumer side Pact testing is an isolated test that ensures a given component is able to collaborate with another (remote) component. Pact will automatically start a Mock server in the background that will act as the collaborators' test double. This implies that any interactions expected on the Mock server will be validated, meaning a test will fail if all interactions were not completed, or if unexpected interactions were found: A typical consumer-side test would look something like this: If this test completed successfully, a Pact file should have been written to ./pacts/my_consumer-my_provider.json containing all of the interactions expected to occur between the Consumer and Provider. In addition to verbatim value matching, you have 3 useful matching functions in the `dsl` package that can increase expressiveness and reduce brittle test cases. Here is a complex example that shows how all 3 terms can be used together: colour := Term("red", "red|green|blue") match := EachLike( This example will result in a response body from the mock server that looks like: See the examples in the dsl package and the matcher tests (https://github.com/pact-foundation/pact-go/blob/master/dsl/matcher_test.go) for more matching examples. NOTE: You will need to use valid Ruby regular expressions (http://ruby-doc.org/core-2.1.5/Regexp.html) and double escape backslashes. Read more about flexible matching (https://github.com/pact-foundation/pact-ruby/wiki/Regular-expressions-and-type-matching-with-Pact. Provider side Pact testing, involves verifying that the contract - the Pact file - can be satisfied by the Provider. A typical Provider side test would like something like: The `VerifyProvider` will handle all verifications, treating them as subtests and giving you granular test reporting. If you don't like this behaviour, you may call `VerifyProviderRaw` directly and handle the errors manually. Note that `PactURLs` may be a list of local pact files or remote based urls (possibly from a Pact Broker - http://docs.pact.io/documentation/sharings_pacts.html). Pact reads the specified pact files (from remote or local sources) and replays the interactions against a running Provider. If all of the interactions are met we can say that both sides of the contract are satisfied and the test passes. When validating a Provider, you have 3 options to provide the Pact files: 1. Use "PactURLs" to specify the exact set of pacts to be replayed: 2. Use "PactBroker" to automatically find all of the latest consumers: 3. Use "PactBroker" and "Tags" to automatically find all of the latest consumers: Options 2 and 3 are particularly useful when you want to validate that your Provider is able to meet the contracts of what's in Production and also the latest in development. See this [article](http://rea.tech/enter-the-pact-matrix-or-how-to-decouple-the-release-cycles-of-your-microservices/) for more on this strategy. Each interaction in a pact should be verified in isolation, with no context maintained from the previous interactions. So how do you test a request that requires data to exist on the provider? Provider states are how you achieve this using Pact. Provider states also allow the consumer to make the same request with different expected responses (e.g. different response codes, or the same resource with a different subset of data). States are configured on the consumer side when you issue a dsl.Given() clause with a corresponding request/response pair. Configuring the provider is a little more involved, and (currently) requires running an API endpoint to configure any [provider states](http://docs.pact.io/documentation/provider_states.html) during the verification process. The option you must provide to the dsl.VerifyRequest is: An example route using the standard Go http package might look like this: See the examples or read more at http://docs.pact.io/documentation/provider_states.html. See the Pact Broker (http://docs.pact.io/documentation/sharings_pacts.html) documentation for more details on the Broker and this article (http://rea.tech/enter-the-pact-matrix-or-how-to-decouple-the-release-cycles-of-your-microservices/) on how to make it work for you. Publishing using Go code: Publishing from the CLI: Use a cURL request like the following to PUT the pact to the right location, specifying your consumer name, provider name and consumer version. The following flags are required to use basic authentication when publishing or retrieving Pact files to/from a Pact Broker: Pact Go uses a simple log utility (logutils - https://github.com/hashicorp/logutils) to filter log messages. The CLI already contains flags to manage this, should you want to control log level in your tests, you can set it like so:
Package goa provides the runtime support for goa microservices. goa service development begins with writing the *design* of a service. The design is described using the goa language implemented by the github.com/goadesign/goa/design/apidsl package. The `goagen` tool consumes the metadata produced from executing the design language to generate service specific code that glues the underlying HTTP server with action specific code and data structures. The goa package contains supporting functionality for the generated code including basic request and response state management through the RequestData and ResponseData structs, error handling via error classes, middleware support via the Middleware data structure as well as decoding and encoding algorithms. The RequestData and ResponseData structs provides access to the request and response state. goa request handlers also accept a context.Context interface as first parameter so that deadlines and cancelation signals may easily be implemented. The request state exposes the underlying http.Request object as well as the deserialized payload (request body) and parameters (both path and querystring parameters). Generated action specific contexts wrap the context.Context, ResponseData and RequestData data structures. They expose properly typed fields that correspond to the request parameters and body data structure descriptions appearing in the design. The response state exposes the response status and body length as well as the underlying ResponseWriter. Action contexts provide action specific helper methods that write the responses as described in the design optionally taking an instance of the media type for responses that contain a body. Here is an example showing an "update" action corresponding to following design (extract): The action signature generated by goagen is: where UpdateBottleContext is: and implements: The definitions of the Bottle and UpdateBottlePayload data structures are ommitted for brievity. There is one controller interface generated per resource defined via the design language. The interface exposes the controller actions. User code must provide data structures that implement these interfaces when mounting a controller onto a service. The controller data structure should include an anonymous field of type *goa.Controller which takes care of implementing the middleware handling. A goa middleware is a function that takes and returns a Handler. A Handler is a the low level function which handles incoming HTTP requests. goagen generates the handlers code so each handler creates the action specific context and calls the controller action with it. Middleware can be added to a goa service or a specific controller using the corresponding Use methods. goa comes with a few stock middleware that handle common needs such as logging, panic recovery or using the RequestID header to trace requests across multiple services. The controller action methods generated by goagen such as the Update method of the BottleController interface shown above all return an error value. goa defines an Error struct that action implementations can use to describe the content of the corresponding HTTP response. Errors can be created using error classes which are functions created via NewErrorClass. The ErrorHandler middleware maps errors to HTTP responses. Errors that are instances of the Error struct are mapped using the struct fields while other types of errors return responses with status code 500 and the error message in the body. The goa design language documented in the dsl package makes it possible to attach validations to data structure definitions. One specific type of validation consists of defining the format that a data structure string field must follow. Example of formats include email, data time, hostnames etc. The ValidateFormat function provides the implementation for the format validation invoked from the code generated by goagen. The goa design language makes it possible to specify the encodings supported by the API both as input (Consumes) and output (Produces). goagen uses that information to registed the corresponding packages with the service encoders and decoders via their Register methods. The service exposes the DecodeRequest and EncodeResponse that implement a simple content type negotiation algorithm for picking the right encoder for the "Content-Type" (decoder) or "Accept" (encoder) request header. Package goa standardizes on structured error responses: a request that fails because of an invalid input or an unexpected condition produces a response that contains a structured error. The error data structures returned to clients contains five fields: an ID, a code, a status, a detail and metadata. The ID is unique for the occurrence of the error, it helps correlate the content of the response with the content of the service logs. The code defines the class of error (e.g. "invalid_parameter_type") and the status the corresponding HTTP status (e.g. 400). The detail contains a message specific to the error occurrence. The metadata contains key/value pairs that provide contextual information (name of parameters, value of invalid parameter etc.). Instances of Error can be created via Error Class functions. See http://goa.design/implement/error_handling.html All instance of errors created via a error class implement the ServiceError interface. This interface is leveraged by the error handler middleware to produce the error responses. The code generated by goagen calls the helper functions exposed in this file when it encounters invalid data (wrong type, validation errors etc.) such as InvalidParamTypeError, InvalidAttributeTypeError etc. These methods return errors that get merged with any previously encountered error via the Error Merge method. The helper functions are error classes stored in global variable. This means your code can override their values to produce arbitrary error responses. goa includes an error handler middleware that takes care of mapping back any error returned by previously called middleware or action handler into HTTP responses. If the error was created via an error class then the corresponding content including the HTTP status is used otherwise an internal error is returned. Errors that bubble up all the way to the top (i.e. not handled by the error middleware) also generate an internal error response.
Package goa provides the runtime support for goa microservices. goa service development begins with writing the *design* of a service. The design is described using the goa language implemented by the github.com/goadesign/goa/design/apidsl package. The `goagen` tool consumes the metadata produced from executing the design language to generate service specific code that glues the underlying HTTP server with action specific code and data structures. The goa package contains supporting functionality for the generated code including basic request and response state management through the RequestData and ResponseData structs, error handling via error classes, middleware support via the Middleware data structure as well as decoding and encoding algorithms. The RequestData and ResponseData structs provides access to the request and response state. goa request handlers also accept a golang.org/x/net/Context interface as first parameter so that deadlines and cancelation signals may easily be implemented. The request state exposes the underlying http.Request object as well as the deserialized payload (request body) and parameters (both path and querystring parameters). Generated action specific contexts wrap the context.Context, ResponseData and RequestData data structures. They expose properly typed fields that correspond to the request parameters and body data structure descriptions appearing in the design. The response state exposes the response status and body length as well as the underlying ResponseWriter. Action contexts provide action specific helper methods that write the responses as described in the design optionally taking an instance of the media type for responses that contain a body. Here is an example showing an "update" action corresponding to following design (extract): The action signature generated by goagen is: where UpdateBottleContext is: and implements: The definitions of the Bottle and UpdateBottlePayload data structures are ommitted for brievity. There is one controller interface generated per resource defined via the design language. The interface exposes the controller actions. User code must provide data structures that implement these interfaces when mounting a controller onto a service. The controller data structure should include an anonymous field of type *goa.Controller which takes care of implementing the middleware handling. A goa middleware is a function that takes and returns a Handler. A Handler is a the low level function which handles incoming HTTP requests. goagen generates the handlers code so each handler creates the action specific context and calls the controller action with it. Middleware can be added to a goa service or a specific controller using the corresponding Use methods. goa comes with a few stock middleware that handle common needs such as logging, panic recovery or using the RequestID header to trace requests across multiple services. The controller action methods generated by goagen such as the Update method of the BottleController interface shown above all return an error value. goa defines an Error struct that action implementations can use to describe the content of the corresponding HTTP response. Errors can be created using error classes which are functions created via NewErrorClass. The ErrorHandler middleware maps errors to HTTP responses. Errors that are instances of the Error struct are mapped using the struct fields while other types of errors return responses with status code 500 and the error message in the body. The goa design language documented in the dsl package makes it possible to attach validations to data structure definitions. One specific type of validation consists of defining the format that a data structure string field must follow. Example of formats include email, data time, hostnames etc. The ValidateFormat function provides the implementation for the format validation invoked from the code generated by goagen. The goa design language makes it possible to specify the encodings supported by the API both as input (Consumes) and output (Produces). goagen uses that information to registed the corresponding packages with the service encoders and decoders via their Register methods. The service exposes the DecodeRequest and EncodeResponse that implement a simple content type negotiation algorithm for picking the right encoder for the "Content-Type" (decoder) or "Accept" (encoder) request header. Package goa standardizes on structured error responses: a request that fails because of an invalid input or an unexpected condition produces a response that contains a structured error. The Error data structure contains four fields: a code, a status, a detail and metadata. The code defines the class of error (e.g. "invalid_parameter_type") and the status the corresponding HTTP status (e.g. 400). The detail contains a message specific to the error occurrence. The medata contains key/value pairs that provide contextual information (name of parameters, value of invalid parameter etc.). The basic data structure backing errors is Error. Instances of Error can be created via Error Class functions. See http://goa.design/implement/error_handling.html The code generated by goagen calls the helper functions exposed in this file when it encounters invalid data (wrong type, validation errors etc.) such as InvalidParamTypeError, InvalidAttributeTypeError etc. These methods return errors that get merged with any previously encountered error via the Error Merge method. goa includes an error handler middleware that takes care of mapping back any error returned by previously called middleware or action handler into HTTP responses. If the error is an instance of Error then the corresponding content including the HTTP status is used otherwise an internal error is returned. Errors that bubble up all the way to the top (i.e. not handled by the error middleware) also generate an internal error response.
Package p9p implements a compliant 9P2000 client and server library for use in modern, production Go services. This package differentiates itself in that is has departed from the plan 9 implementation primitives and better follows idiomatic Go style. The package revolves around the session type, which is an enumeration of raw 9p message calls. A few calls, such as flush and version, have been elided, deferring their usage to the server implementation. Sessions can be trivially proxied through clients and servers. The best place to get started is with Serve. Serve can be provided a connection and a handler. A typical implementation will call Serve as part of a listen/accept loop. As each network connection is created, Serve can be called with a handler for the specific connection. The handler can be implemented with a Session via the Dispatch function or can generate sessions for dispatch in response to client messages. (See cmd/9ps for an example) On the client side, NewSession provides a 9p session from a connection. After a version negotiation, methods can be called on the session, in parallel, and calls will be sent over the connection. Call timeouts can be controlled via the context provided to each method call. This package has the beginning of a nice client-server framework for working with 9p. Some of the abstractions aren't entirely fleshed out, but most of this can center around the Handler. Missing from this are a number of tools for implementing 9p servers. The most glaring are directory read and walk helpers. Other, more complex additions might be a system to manage in memory filesystem trees that expose multi-user sessions. The largest difference between this package and other 9p packages is simplification of the types needed to implement a server. To avoid confusing bugs and odd behavior, the components are separated by each level of the protocol. One example is that requests and responses are separated and they no longer hold mutable state. This means that framing, transport management, encoding, and dispatching are componentized. Little work will be required to swap out encodings, transports or connection implementations. This package has been wired from top to bottom to support context-based resource management. Everything from startup to shutdown can have timeouts using contexts. Not all close methods are fully in place, but we are very close to having controlled, predictable cleanup for both servers and clients. Timeouts can be very granular or very course, depending on the context of the timeout. For example, it is very easy to set a short timeout for a stat call but a long timeout for reading data. Currently, there is not multiversion support. The hooks and functionality are in place to add multi-version support. Generally, the correct space to do this is in the codec. Types, such as Dir, simply need to be extended to support the possibility of extra fields. The real question to ask here is what is the role of the version number in the 9p protocol. It really comes down to the level of support required. Do we just need it at the protocol level, or do handlers and sessions need to be have differently based on negotiated versions? This package has a number of TODOs to make it easier to use. Most of the existing code provides a solid base to work from. Don't be discouraged by the sawdust. In addition, the testing is embarassingly lacking. With time, we can get full testing going and ensure we have confidence in the implementation.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates • Barcodes gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. In particular, languages that require more than one code page such as Chinese, Japanese, and Arabic are not currently supported. This is explained in issue 109. However, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.SummaryCompare() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package autorest implements an HTTP request pipeline suitable for use across multiple go-routines and provides the shared routines relied on by AutoRest (see https://github.com/Azure/autorest/) generated Go code. The package breaks sending and responding to HTTP requests into three phases: Preparing, Sending, and Responding. A typical pattern is: Each phase relies on decorators to modify and / or manage processing. Decorators may first modify and then pass the data along, pass the data first and then modify the result, or wrap themselves around passing the data (such as a logger might do). Decorators run in the order provided. For example, the following: will set the URL to: Preparers and Responders may be shared and re-used (assuming the underlying decorators support sharing and re-use). Performant use is obtained by creating one or more Preparers and Responders shared among multiple go-routines, and a single Sender shared among multiple sending go-routines, all bound together by means of input / output channels. Decorators hold their passed state within a closure (such as the path components in the example above). Be careful to share Preparers and Responders only in a context where such held state applies. For example, it may not make sense to share a Preparer that applies a query string from a fixed set of values. Similarly, sharing a Responder that reads the response body into a passed struct (e.g., ByUnmarshallingJson) is likely incorrect. Lastly, the Swagger specification (https://swagger.io) that drives AutoRest (https://github.com/Azure/autorest/) precisely defines two date forms: date and date-time. The github.com/Azure/go-autorest/autorest/date package provides time.Time derivations to ensure correct parsing and formatting. Errors raised by autorest objects and methods will conform to the autorest.Error interface. See the included examples for more detail. For details on the suggested use of this package by generated clients, see the Client described below.
This package is the root package of the govmomi library. The library is structured as follows: The minimal usable functionality is available through the vim25 package. It contains subpackages that contain generated types, managed objects, and all available methods. The vim25 package is entirely independent of the other packages in the govmomi tree -- it has no dependencies on its peers. The vim25 package itself contains a client structure that is passed around throughout the entire library. It abstracts a session and its immutable state. See the vim25 package for more information. The session package contains an abstraction for the session manager that allows a user to login and logout. It also provides access to the current session (i.e. to determine if the user is in fact logged in) The object package contains wrappers for a selection of managed objects. The constructors of these objects all take a *vim25.Client, which they pass along to derived objects, if applicable. The govc package contains the govc CLI. The code in this tree is not intended to be used as a library. Any functionality that govc contains that _could_ be used as a library function but isn't, _should_ live in a root level package. Other packages, such as "event", "guest", or "license", provide wrappers for the respective subsystems. They are typically not needed in normal workflows so are kept outside the object package.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
This package is the root package of the govmomi library. The library is structured as follows: The minimal usable functionality is available through the vim25 package. It contains subpackages that contain generated types, managed objects, and all available methods. The vim25 package is entirely independent of the other packages in the govmomi tree -- it has no dependencies on its peers. The vim25 package itself contains a client structure that is passed around throughout the entire library. It abstracts a session and its immutable state. See the vim25 package for more information. The session package contains an abstraction for the session manager that allows a user to login and logout. It also provides access to the current session (i.e. to determine if the user is in fact logged in) The object package contains wrappers for a selection of managed objects. The constructors of these objects all take a *vim25.Client, which they pass along to derived objects, if applicable. The govc package contains the govc CLI. The code in this tree is not intended to be used as a library. Any functionality that govc contains that _could_ be used as a library function but isn't, _should_ live in a root level package. Other packages, such as "event", "guest", or "license", provide wrappers for the respective subsystems. They are typically not needed in normal workflows so are kept outside the object package.
Package swf provides the client and types for making API requests to Amazon Simple Workflow Service. The Amazon Simple Workflow Service (Amazon SWF) makes it easy to build applications that use Amazon's cloud to coordinate work across distributed components. In Amazon SWF, a task represents a logical unit of work that is performed by a component of your workflow. Coordinating tasks in a workflow involves managing intertask dependencies, scheduling, and concurrency in accordance with the logical flow of the application. Amazon SWF gives you full control over implementing tasks and coordinating them without worrying about underlying complexities such as tracking their progress and maintaining their state. This documentation serves as reference only. For a broader overview of the Amazon SWF programming model, see the Amazon SWF Developer Guide (http://docs.aws.amazon.com/amazonswf/latest/developerguide/). See swf package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/swf/ To Amazon Simple Workflow Service with the SDK use the New function to create a new service client. With that client you can make API requests to the service. These clients are safe to use concurrently. See the SDK's documentation for more information on how to use the SDK. https://docs.aws.amazon.com/sdk-for-go/api/ See aws.Config documentation for more information on configuring SDK clients. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config See the Amazon Simple Workflow Service client SWF for more information on creating client for this service. https://docs.aws.amazon.com/sdk-for-go/api/service/swf/#New
Package autorest implements an HTTP request pipeline suitable for use across multiple go-routines and provides the shared routines relied on by AutoRest (see https://github.com/Azure/autorest/) generated Go code. The package breaks sending and responding to HTTP requests into three phases: Preparing, Sending, and Responding. A typical pattern is: Each phase relies on decorators to modify and / or manage processing. Decorators may first modify and then pass the data along, pass the data first and then modify the result, or wrap themselves around passing the data (such as a logger might do). Decorators run in the order provided. For example, the following: will set the URL to: Preparers and Responders may be shared and re-used (assuming the underlying decorators support sharing and re-use). Performant use is obtained by creating one or more Preparers and Responders shared among multiple go-routines, and a single Sender shared among multiple sending go-routines, all bound together by means of input / output channels. Decorators hold their passed state within a closure (such as the path components in the example above). Be careful to share Preparers and Responders only in a context where such held state applies. For example, it may not make sense to share a Preparer that applies a query string from a fixed set of values. Similarly, sharing a Responder that reads the response body into a passed struct (e.g., ByUnmarshallingJson) is likely incorrect. Lastly, the Swagger specification (https://swagger.io) that drives AutoRest (https://github.com/Azure/autorest/) precisely defines two date forms: date and date-time. The github.com/Azure/go-autorest/autorest/date package provides time.Time derivations to ensure correct parsing and formatting. Errors raised by autorest objects and methods will conform to the autorest.Error interface. See the included examples for more detail. For details on the suggested use of this package by generated clients, see the Client described below.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. However, support is provided to translate UTF-8 runes to code page encodings. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename and summary. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. Contributions that do not directly pertain to the core functionality of gofpdf should be placed in their own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retreived with the output call where it can be handled by the application.
This package is the root package of the govmomi library. The library is structured as follows: The minimal usable functionality is available through the vim25 package. It contains subpackages that contain generated types, managed objects, and all available methods. The vim25 package is entirely independent of the other packages in the govmomi tree -- it has no dependencies on its peers. The vim25 package itself contains a client structure that is passed around throughout the entire library. It abstracts a session and its immutable state. See the vim25 package for more information. The session package contains an abstraction for the session manager that allows a user to login and logout. It also provides access to the current session (i.e. to determine if the user is in fact logged in) The object package contains wrappers for a selection of managed objects. The constructors of these objects all take a *vim25.Client, which they pass along to derived objects, if applicable. The govc package contains the govc CLI. The code in this tree is not intended to be used as a library. Any functionality that govc contains that _could_ be used as a library function but isn't, _should_ live in a root level package. Other packages, such as "event", "guest", or "license", provide wrappers for the respective subsystems. They are typically not needed in normal workflows so are kept outside the object package.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package acquire manages the flow and status of an acquire game. It acts like a finite state machine (FSM), in which received inputs modify machine state
Package v8 provides a Go API for the the V8 javascript engine. This allows running javascript within a go executable. The bindings have been tested with v8 builds between 5.1.281.16 through 6.7.77. V8 provides two main concepts for managing javascript state: Isolates and Contexts. An isolate represents a single-threaded javascript engine that can manage one or more contexts. A context is a sandboxed javascript execution environment. Thus, if you have one isolate, you could safely execute independent code in many different contexts created in that isolate. The code in the various contexts would not interfere with each other, however no more than one context would ever be executing at a given time. If you have multiple isolates, they may be executing in separate threads simultaneously. This work is based off of several existing libraries:
Package autorest implements an HTTP request pipeline suitable for use across multiple go-routines and provides the shared routines relied on by AutoRest (see https://github.com/Azure/autorest/) generated Go code. The package breaks sending and responding to HTTP requests into three phases: Preparing, Sending, and Responding. A typical pattern is: Each phase relies on decorators to modify and / or manage processing. Decorators may first modify and then pass the data along, pass the data first and then modify the result, or wrap themselves around passing the data (such as a logger might do). Decorators run in the order provided. For example, the following: will set the URL to: Preparers and Responders may be shared and re-used (assuming the underlying decorators support sharing and re-use). Performant use is obtained by creating one or more Preparers and Responders shared among multiple go-routines, and a single Sender shared among multiple sending go-routines, all bound together by means of input / output channels. Decorators hold their passed state within a closure (such as the path components in the example above). Be careful to share Preparers and Responders only in a context where such held state applies. For example, it may not make sense to share a Preparer that applies a query string from a fixed set of values. Similarly, sharing a Responder that reads the response body into a passed struct (e.g., ByUnmarshallingJson) is likely incorrect. Lastly, the Swagger specification (https://swagger.io) that drives AutoRest (https://github.com/Azure/autorest/) precisely defines two date forms: date and date-time. The github.com/Azure/go-autorest/autorest/date package provides time.Time derivations to ensure correct parsing and formatting. Errors raised by autorest objects and methods will conform to the autorest.Error interface. See the included examples for more detail. For details on the suggested use of this package by generated clients, see the Client described below.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. • Choice of measurement unit, page format and margins • Page header and footer management • Automatic page breaks, line breaks, and text justification • Inclusion of JPEG, PNG, GIF and basic path-only SVG images • Colors, gradients and alpha channel transparency • Outline bookmarks • Internal and external links • TrueType, Type1 and encoding support • Page compression • Lines, Bézier curves, arcs, and ellipses • Rotation, scaling, skewing, translation, and mirroring • Clipping • Document protection • Layers • Templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. Like FPDF version 1.7, from which gofpdf is derived, this package does not yet support UTF-8 fonts. However, support is provided to translate UTF-8 runes to code page encodings. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running "go test ./..." is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you'll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory. The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). In order to use a different TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run "go build". This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include http://www.google.com/fonts/ and http://dejavu-fonts.org/. The draw2d package (https://github.com/llgcode/draw2d) is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the `contrib` directory. Here are guidelines for making submissions. Your change should • be compatible with the MIT License • be properly documented • be formatted with `go fmt` • include an example in fpdf_test.go if appropriate • conform to the standards of golint (https://github.com/golang/lint) and go vet (https://godoc.org/golang.org/x/tools/cmd/vet), that is, `golint .` and `go vet .` should not generate any warnings • not diminish test coverage (https://blog.golang.org/cover) Pull requests (https://help.github.com/articles/using-pull-requests/) work nicely as a means of contributing your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package's code and documentation are closely derived from the FPDF library (http://www.fpdf.org/) created by Olivier Plathey, and a number of font and image resources are copied directly from it. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image's extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Additionally, he augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Bruno Michel has provided valuable assistance with the code. • Handle UTF-8 source text natively. Until then, automatic translation of UTF-8 runes to code page bytes is provided. • Improve test coverage as reported by the coverage tool. This example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retreived with the output call where it can be handled by the application.
Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. To install the package on your system, run Later, to receive updates, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.
Package sdk is the official AWS SDK for the Go programming language. The AWS SDK for Go provides APIs and utilities that developers can use to build Go applications that use AWS services, such as Amazon Elastic Compute Cloud (Amazon EC2) and Amazon Simple Storage Service (Amazon S3). The SDK removes the complexity of coding directly against a web service interface. It hides a lot of the lower-level plumbing, such as authentication, request retries, and error handling. The SDK also includes helpful utilities on top of the AWS APIs that add additional capabilities and functionality. For example, the Amazon S3 Download and Upload Manager will automatically split up large objects into multiple parts and transfer them concurrently. See the s3manager package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/s3/s3manager/ Checkout the Getting Started Guide and API Reference Docs detailed the SDK's components and details on each AWS client the SDK supports. The Getting Started Guide provides examples and detailed description of how to get setup with the SDK. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/welcome.html The API Reference Docs include a detailed breakdown of the SDK's components such as utilities and AWS clients. Use this as a reference of the Go types included with the SDK, such as AWS clients, API operations, and API parameters. https://docs.aws.amazon.com/sdk-for-go/api/ The SDK is composed of two main components, SDK core, and service clients. The SDK core packages are all available under the aws package at the root of the SDK. Each client for a supported AWS service is available within its own package under the service folder at the root of the SDK. aws - SDK core, provides common shared types such as Config, Logger, and utilities to make working with API parameters easier. awserr - Provides the error interface that the SDK will use for all errors that occur in the SDK's processing. This includes service API response errors as well. The Error type is made up of a code and message. Cast the SDK's returned error type to awserr.Error and call the Code method to compare returned error to specific error codes. See the package's documentation for additional values that can be extracted such as RequestId. credentials - Provides the types and built in credentials providers the SDK will use to retrieve AWS credentials to make API requests with. Nested under this folder are also additional credentials providers such as stscreds for assuming IAM roles, and ec2rolecreds for EC2 Instance roles. endpoints - Provides the AWS Regions and Endpoints metadata for the SDK. Use this to lookup AWS service endpoint information such as which services are in a region, and what regions a service is in. Constants are also provided for all region identifiers, e.g UsWest2RegionID for "us-west-2". session - Provides initial default configuration, and load configuration from external sources such as environment and shared credentials file. request - Provides the API request sending, and retry logic for the SDK. This package also includes utilities for defining your own request retryer, and configuring how the SDK processes the request. service - Clients for AWS services. All services supported by the SDK are available under this folder. The SDK includes the Go types and utilities you can use to make requests to AWS service APIs. Within the service folder at the root of the SDK you'll find a package for each AWS service the SDK supports. All service clients follows a common pattern of creation and usage. When creating a client for an AWS service you'll first need to have a Session value constructed. The Session provides shared configuration that can be shared between your service clients. When service clients are created you can pass in additional configuration via the aws.Config type to override configuration provided by in the Session to create service client instances with custom configuration. Once the service's client is created you can use it to make API requests the AWS service. These clients are safe to use concurrently. In the AWS SDK for Go, you can configure settings for service clients, such as the log level and maximum number of retries. Most settings are optional; however, for each service client, you must specify a region and your credentials. The SDK uses these values to send requests to the correct AWS region and sign requests with the correct credentials. You can specify these values as part of a session or as environment variables. See the SDK's configuration guide for more information. https://docs.aws.amazon.com/sdk-for-go/v1/developer-guide/configuring-sdk.html See the session package documentation for more information on how to use Session with the SDK. https://docs.aws.amazon.com/sdk-for-go/api/aws/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config When using the SDK you'll generally need your AWS credentials to authenticate with AWS services. The SDK supports multiple methods of supporting these credentials. By default the SDK will source credentials automatically from its default credential chain. See the session package for more information on this chain, and how to configure it. The common items in the credential chain are the following: Environment Credentials - Set of environment variables that are useful when sub processes are created for specific roles. Shared Credentials file (~/.aws/credentials) - This file stores your credentials based on a profile name and is useful for local development. EC2 Instance Role Credentials - Use EC2 Instance Role to assign credentials to application running on an EC2 instance. This removes the need to manage credential files in production. Credentials can be configured in code as well by setting the Config's Credentials value to a custom provider or using one of the providers included with the SDK to bypass the default credential chain and use a custom one. This is helpful when you want to instruct the SDK to only use a specific set of credentials or providers. This example creates a credential provider for assuming an IAM role, "myRoleARN" and configures the S3 service client to use that role for API requests. See the credentials package documentation for more information on credential providers included with the SDK, and how to customize the SDK's usage of credentials. https://docs.aws.amazon.com/sdk-for-go/api/aws/credentials The SDK has support for the shared configuration file (~/.aws/config). This support can be enabled by setting the environment variable, "AWS_SDK_LOAD_CONFIG=1", or enabling the feature in code when creating a Session via the Option's SharedConfigState parameter. In addition to the credentials you'll need to specify the region the SDK will use to make AWS API requests to. In the SDK you can specify the region either with an environment variable, or directly in code when a Session or service client is created. The last value specified in code wins if the region is specified multiple ways. To set the region via the environment variable set the "AWS_REGION" to the region you want to the SDK to use. Using this method to set the region will allow you to run your application in multiple regions without needing additional code in the application to select the region. The endpoints package includes constants for all regions the SDK knows. The values are all suffixed with RegionID. These values are helpful, because they reduce the need to type the region string manually. To set the region on a Session use the aws package's Config struct parameter Region to the AWS region you want the service clients created from the session to use. This is helpful when you want to create multiple service clients, and all of the clients make API requests to the same region. See the endpoints package for the AWS Regions and Endpoints metadata. https://docs.aws.amazon.com/sdk-for-go/api/aws/endpoints/ In addition to setting the region when creating a Session you can also set the region on a per service client bases. This overrides the region of a Session. This is helpful when you want to create service clients in specific regions different from the Session's region. See the Config type in the aws package for more information and additional options such as setting the Endpoint, and other service client configuration options. https://docs.aws.amazon.com/sdk-for-go/api/aws/#Config Once the client is created you can make an API request to the service. Each API method takes a input parameter, and returns the service response and an error. The SDK provides methods for making the API call in multiple ways. In this list we'll use the S3 ListObjects API as an example for the different ways of making API requests. ListObjects - Base API operation that will make the API request to the service. ListObjectsRequest - API methods suffixed with Request will construct the API request, but not send it. This is also helpful when you want to get a presigned URL for a request, and share the presigned URL instead of your application making the request directly. ListObjectsPages - Same as the base API operation, but uses a callback to automatically handle pagination of the API's response. ListObjectsWithContext - Same as base API operation, but adds support for the Context pattern. This is helpful for controlling the canceling of in flight requests. See the Go standard library context package for more information. This method also takes request package's Option functional options as the variadic argument for modifying how the request will be made, or extracting information from the raw HTTP response. ListObjectsPagesWithContext - same as ListObjectsPages, but adds support for the Context pattern. Similar to ListObjectsWithContext this method also takes the request package's Option function option types as the variadic argument. In addition to the API operations the SDK also includes several higher level methods that abstract checking for and waiting for an AWS resource to be in a desired state. In this list we'll use WaitUntilBucketExists to demonstrate the different forms of waiters. WaitUntilBucketExists. - Method to make API request to query an AWS service for a resource's state. Will return successfully when that state is accomplished. WaitUntilBucketExistsWithContext - Same as WaitUntilBucketExists, but adds support for the Context pattern. In addition these methods take request package's WaiterOptions to configure the waiter, and how underlying request will be made by the SDK. The API method will document which error codes the service might return for the operation. These errors will also be available as const strings prefixed with "ErrCode" in the service client's package. If there are no errors listed in the API's SDK documentation you'll need to consult the AWS service's API documentation for the errors that could be returned. Pagination helper methods are suffixed with "Pages", and provide the functionality needed to round trip API page requests. Pagination methods take a callback function that will be called for each page of the API's response. Waiter helper methods provide the functionality to wait for an AWS resource state. These methods abstract the logic needed to to check the state of an AWS resource, and wait until that resource is in a desired state. The waiter will block until the resource is in the state that is desired, an error occurs, or the waiter times out. If a resource times out the error code returned will be request.WaiterResourceNotReadyErrorCode. This example shows a complete working Go file which will upload a file to S3 and use the Context pattern to implement timeout logic that will cancel the request if it takes too long. This example highlights how to use sessions, create a service client, make a request, handle the error, and process the response.
Package gophercloud provides a multi-vendor interface to OpenStack-compatible clouds. The library has a three-level hierarchy: providers, services, and resources. Provider structs represent the cloud providers that offer and manage a collection of services. You will generally want to create one Provider client per OpenStack cloud. Use your OpenStack credentials to create a Provider client. The IdentityEndpoint is typically refered to as "auth_url" or "OS_AUTH_URL" in information provided by the cloud operator. Additionally, the cloud may refer to TenantID or TenantName as project_id and project_name. Credentials are specified like so: You can authenticate with a token by doing: You may also use the openstack.AuthOptionsFromEnv() helper function. This function reads in standard environment variables frequently found in an OpenStack `openrc` file. Again note that Gophercloud currently uses "tenant" instead of "project". Service structs are specific to a provider and handle all of the logic and operations for a particular OpenStack service. Examples of services include: Compute, Object Storage, Block Storage. In order to define one, you need to pass in the parent provider, like so: Resource structs are the domain models that services make use of in order to work with and represent the state of API resources: Intermediate Result structs are returned for API operations, which allow generic access to the HTTP headers, response body, and any errors associated with the network transaction. To turn a result into a usable resource struct, you must call the Extract method which is chained to the response, or an Extract function from an applicable extension: All requests that enumerate a collection return a Pager struct that is used to iterate through the results one page at a time. Use the EachPage method on that Pager to handle each successive Page in a closure, then use the appropriate extraction method from that request's package to interpret that Page as a slice of results: If you want to obtain the entire collection of pages without doing any intermediary processing on each page, you can use the AllPages method: This top-level package contains utility functions and data types that are used throughout the provider and service packages. Of particular note for end users are the AuthOptions and EndpointOpts structs. An example retry backoff function, which respects the 429 HTTP response code and a "Retry-After" header: