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 botstate is a bot state manager for Go.
Package tea implements a high-level framework for building web user interfaces, using the Elm architecture. The user interface consists of an App, which manages a model representing application state. The app responds to messages by updating its model, and re-renders via a virtual dom when the model changes. Messages are processed sequentially in a single goroutine. Applications should define a model type M which implements AppModel[M], and some number of types that implement Message[M]. The app can then be constructed by passing the initial model to NewApp, and then attached to the DOM and executed with App.Run().
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 nifcloud.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/nifcloud/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/nifcloud/#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 (~/.nifcloud/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/nifcloud/credentials The SDK has support for the shared configuration file (~/.nifcloud/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/nifcloud/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/nifcloud/#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. - 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 golangsdk 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 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.
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 godux implements a state management for your backend application. It's inspired in Redux, but with simplest concepts. - State: Your application state don't change. - Actions: Your action is used in reducers, to return new value based on State. - Reducers: Actions describe the fact that something happened, but don’t specify how the application’s state changes in response. This is the job of a reducer. This library was inspired in Redux.
Package peer provides a common base for creating and managing Bitcoin network peers. This package builds upon the wire package, which provides the fundamental primitives necessary to speak the bitcoin 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: Provides a basic concurrent safe bitcoin peer for handling bitcoin communications via the peer-to-peer protocol Full duplex reading and writing of bitcoin protocol messages Automatic handling of the initial handshake process including protocol version negotiation Asynchronous message queuing of outbound messages with optional channel for notification when the message is actually sent Flexible peer configuration Caller is responsible for creating outgoing connections and listening for incoming connections so they have flexibility to establish connections asthey see fit (proxies, etc) User agent name and version Bitcoin network Service support signalling (full nodes, bloom filters, etc) Maximum supported protocol version Ability to register callbacks for handling bitcoin protocol messages Inventory message batching and send trickling with known inventory detection and avoidance Automatic periodic keep-alive pinging and pong responses Random Nonce generation and self connection detection Proper handling of bloom filter related commands when the caller does not specify the related flag to signal support Disconnects the peer when the protocol version is high enough Does not invoke the related callbacks for older protocol versions Snapshottable peer statistics such as the total number of bytes read and written, the remote address, user agent, and negotiated protocol version Helper functions pushing addresses, getblocks, getheaders, and reject messages These could all be sent manually via the standard message output function, but the helpers provide additional nice functionality such as duplicate filtering and address randomization Ability to wait for shutdown/disconnect Comprehensive test coverage 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 bitcoin network to use, which services it supports, and callbacks to invoke when bitcoin 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 bitcoin 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 bitcoin 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 BIPS supported by the wire package. (https://godoc.org/github.com/p9c/pod/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 fyner provides a declarative wrapper around the Fyne UI library. Fyner's approach to structuring the UI and state management of an app is very difference from Fyne's. Fyner provides its own set of widgets that wrap the basic Fyne widgets, providing similar functionality but in a far more declarative way. To differentiate, Fyner refers to its own widgets as "components". Fyner components are instantiated manually as struct pointer literals. They export a number of fields which may be set, some of which are of a type from the state package. The fields of a component should not be changed after it is created, though if any of the fields are mutable state types, they may be set via the state API. For example, to create a center-layout container that contains a single label: To interact with the typical Fyne UI system, a Content function is provided that turns a Fyner component into a Fyne CanvasObject. This is typically only used at the top-level in order to set the content of a window, hence the name, but it can actually be used anywhere that a client might want to insert a component into a regular Fyne UI layout. To illustrate the whole system, here's a complete example:
Package jobqueue manages running and scheduling jobs. Applications using jobqueue first create a Manager. One manager handles one or more topics. There is one processor per topic. Applications need to register topics and their processors before starting the manager. Once started, the manager initializes the list of workers that will work on the actual jobs. At the beginning, all workers are idle. The manager has a Store to implement persistent storage. By default, an in memory store is used. There is a MySQL-based persistent store in the "mysql" package. New jobs are added to the manager via the Add method. The manager asks the store to create the job. A scheduler inside manager periodically asks the Store for jobs in the Waiting state. The scheduler will tell idle workers to handle those jobs. The number of concurrent jobs can be specified via the manager option SetConcurrency. A job in jobqueue has always in one of these four states: Waiting (to be executed), Working (currently busy working on a job), Succeeded (completed successfully), and Failed (failed to complete successfully even after retrying). A job can be configured to be retried. To do so, specify the MaxRetry field in Job. Only if the number of retries exceeds the MaxRetry value, the job gets marked as failed. Otherwise, it gets put back into Waiting state and rescheduled (after an some backoff time). The backoff function is exponential by default (see backoff.go). However, one can specify a custom backoff function by the manager option SetBackoffFunc. If the manager crashes and gets restarted, the Store gets started via the Start method. This gives the store implementation a chance to do cleanup. E.g. the MySQL-based store implementation moves all jobs still marked as Working into the Failed state. Notice that you are responsible to prevent that two concurrent managers try to access the same database!
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 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 also use AK/SK authentication to construct provider: 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.
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/shogo82148/goa-v1/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 omitted for brevity. 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 registered 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.
Extensible Go library for creating fast, SSR-first frontend avoiding vanilla templating downsides. Creating asynchronous and dynamic layout parts is a complex problem for larger projects using `html/template`. Library tries to simplify this process. Let's go straight into a simple example. Then, we will dig into details, step by step, how it works. Kyoto provides a simple net/http handlers and function wrappers to handle pages rendering and serving. See functions inside of nethttp.go file for details and advanced usage. Example: Kyoto provides a way to define components. It's a very common approach for modern libraries to manage frontend parts. In kyoto each component is a context receiver, which returns it's state. Each component becomes a part of the page or top-level component, which executes component asynchronously and gets a state future object. In that way your components are executing in a non-blocking way. Pages are just top-level components, where you can configure rendering and page related stuff. Example: As an option, you can wrap component with another function to accept additional paramenters from top-level page/component. Example: Kyoto provides a context, which holds common objects like http.ResponseWriter, *http.Request, etc. See kyoto.Context for details. Example: Kyoto provides a set of parameters and functions to provide a comfortable template building process. You can configure template building parameters with kyoto.TemplateConf configuration. See template.go for available functions and kyoto.TemplateConfiguration for configuration details. Example: Kyoto provides a way to simplify building dynamic UIs. For this purpose it has a feature named actions. Logic is pretty simple. Client calls an action (sends a request to the server). Action is executing on server side and server is sending updated component markup to the client which will be morphed into DOM. That's it. To use actions, you need to go through a few steps. You'll need to include a client into page (JS functions for communication) and register an actions handler for a needed component. Let's start from including a client. Then, let's register an actions handler for a needed component. That's all! Now we ready to use actions to provide a dynamic UI. Example: In this example you can see provided modifications to the quick start example. First, we've added a state and name into our components' markup. In this way we are saving our components' state between actions and find a component root. Unfortunately, we have to manually provide a component name for now, we haven't found a way to provide it dynamically. Second, we've added a reload button with onclick function call. We're using a function Action provided by a client. Action triggering will be described in details later. Third, we've added an action handler inside of our component. This handler will be executed when a client calls an action with a corresponding name. It's highly recommended to keep components' state as small as possible. It will be transmitted on each action call. Kyoto have multiple ways to trigger actions. Now we will check them one by one. This is the simplest way to trigger an action. It's just a function call with a referer (usually 'this', f.e. button) as a first argument (used to determine root), action name as a second argument and arguments as a rest. Arguments must to be JSON serializable. It's possible to trigger an action of another component. If you want to call an action of parent component, use $ prefix in action name. If you want to call an action of component by id, use <id:action> as an action name. This is a specific action which is triggered when a form is submitted. Usually called in onsubmit="..." attribute of a form. You'll need to implement 'Submit' action to handle this trigger. This is a special HTML attribute which will trigger an action on page load. This may be useful for components' lazy loading. With this special HTML attributes you can trigger an action with interval. Useful for components that must to be updated over time (f.e. charts, stats, etc). You can use this trigger with ssa:poll and ssa:poll.interval HTML attributes. This one attribute allows you to trigger an action when an element is visible on the screen. May be useful for lazy loading. Kyoto provides a way to control action flow. For now, it's possible to control display style on component call and push multiple UI updates to the client during a single action. Because kyoto makes a roundtrip to the server every time an action is triggered on the page, there are cases where the page may not react immediately to a user event (like a click). That's why the library provides a way to easily control display attributes on action call. You can use this HTML attribute to control display during action call. At the end of an action the layout will be restored. A small note. Don't forget to set a default display for loading elements like spinners and loaders. You can push multiple component UI updates during a single action call. Just call kyoto.ActionFlush(ctx, state) to initiate an update. Kyoto provides a way to control action rendering. Now there is at least 2 rendering options after an action call: morph (default) and replace. Morph will try to morph received markup to the current one with morphdom library. In case of an error, or explicit "replace" mode, markup will be replaced with x.outerHTML = '...'.
Extensible Go library for creating fast, SSR-first frontend avoiding vanilla templating downsides. Creating asynchronous and dynamic layout parts is a complex problem for larger projects using `html/template`. Library tries to simplify this process. Let's go straight into a simple example. Then, we will dig into details, step by step, how it works. Kyoto provides a simple net/http handlers and function wrappers to handle pages rendering and serving. See functions inside of nethttp.go file for details and advanced usage. Example: Kyoto provides a way to define components. It's a very common approach for modern libraries to manage frontend parts. In kyoto each component is a context receiver, which returns it's state. Each component becomes a part of the page or top-level component, which executes component asynchronously and gets a state future object. In that way your components are executing in a non-blocking way. Pages are just top-level components, where you can configure rendering and page related stuff. Example: As an option, you can wrap component with another function to accept additional paramenters from top-level page/component. Example: Kyoto provides a context, which holds common objects like http.ResponseWriter, *http.Request, etc. See kyoto.Context for details. Example: Kyoto provides a set of parameters and functions to provide a comfortable template building process. You can configure template building parameters with kyoto.TemplateConf configuration. See template.go for available functions and kyoto.TemplateConfiguration for configuration details. Example: Kyoto provides a way to simplify building dynamic UIs. For this purpose it has a feature named actions. Logic is pretty simple. Client calls an action (sends a request to the server). Action is executing on server side and server is sending updated component markup to the client which will be morphed into DOM. That's it. To use actions, you need to go through a few steps. You'll need to include a client into page (JS functions for communication) and register an actions handler for a needed component. Let's start from including a client. Then, let's register an actions handler for a needed component. That's all! Now we ready to use actions to provide a dynamic UI. Example: In this example you can see provided modifications to the quick start example. First, we've added a state and name into our components' markup. In this way we are saving our components' state between actions and find a component root. Unfortunately, we have to manually provide a component name for now, we haven't found a way to provide it dynamically. Second, we've added a reload button with onclick function call. We're using a function Action provided by a client. Action triggering will be described in details later. Third, we've added an action handler inside of our component. This handler will be executed when a client calls an action with a corresponding name. It's highly recommended to keep components' state as small as possible. It will be transmitted on each action call. Kyoto have multiple ways to trigger actions. Now we will check them one by one. This is the simplest way to trigger an action. It's just a function call with a referer (usually 'this', f.e. button) as a first argument (used to determine root), action name as a second argument and arguments as a rest. Arguments must to be JSON serializable. It's possible to trigger an action of another component. If you want to call an action of parent component, use $ prefix in action name. If you want to call an action of component by id, use <id:action> as an action name. This is a specific action which is triggered when a form is submitted. Usually called in onsubmit="..." attribute of a form. You'll need to implement 'Submit' action to handle this trigger. This is a special HTML attribute which will trigger an action on page load. This may be useful for components' lazy loading. With this special HTML attributes you can trigger an action with interval. Useful for components that must to be updated over time (f.e. charts, stats, etc). You can use this trigger with ssa:poll and ssa:poll.interval HTML attributes. This one attribute allows you to trigger an action when an element is visible on the screen. May be useful for lazy loading. Kyoto provides a way to control action flow. For now, it's possible to control display style on component call and push multiple UI updates to the client during a single action. Because kyoto makes a roundtrip to the server every time an action is triggered on the page, there are cases where the page may not react immediately to a user event (like a click). That's why the library provides a way to easily control display attributes on action call. You can use this HTML attribute to control display during action call. At the end of an action the layout will be restored. A small note. Don't forget to set a default display for loading elements like spinners and loaders. You can push multiple component UI updates during a single action call. Just call kyoto.ActionFlush(ctx, state) to initiate an update. Kyoto provides a way to control action rendering. Now there is at least 2 rendering options after an action call: morph (default) and replace. Morph will try to morph received markup to the current one with morphdom library. In case of an error, or explicit "replace" mode, markup will be replaced with x.outerHTML = '...'.
Package kyoto was made for creating fast, server side frontend avoiding vanilla templating downsides. It tries to address complexities in frontend domain like responsibility separation, components structure, asynchronous load and hassle-free dynamic layout updates. These issues are common for frontends written with Go. The library provides you with primitives for pages and components creation, state and rendering management, dynamic layout updates (with external packages integration), utility functions and asynchronous components out of the box. Still, it bundles with minimal dependencies and tries to utilize built-ins as much as possible. You would probably want to opt out from this library in few cases, like, if you're not ready for drastic API changes between major version, you want to develop SPA/PWA and/or complex client-side logic, or you're just feeling OK with your current setup. Please, don't compare kyoto with a popular JS libraries like React, Vue or Svelte. I know you will have such a desire, but most likely you will be wrong. Use cases and underlying principles are just too different. If you want to get an idea of what a typical static component would look like, here's some sample code. It's very ascetic and simplistic, as we don't want to overload you with implementation details. Markup is also not included here (it's just a well-known `html/template`). For details, please check project's website on https://kyoto.codes. Also, you may check the library index to explore available sub-packages and https://pkg.go.dev for Go'ish documentation style. We don't want you to deal with boilerplate code on your own, so you can proceed with our simple starter project. Feel free to use it as an example for your own setup. Components is a common approach for modern libraries to manage frontend parts. Kyoto's components are trying to be mostly independent (but configurable) part of the project. To create component, it would be enough to implement component.Component. It's a function, a context receiver which returns a component state. State is an implementation of component.State, which is easy to implement with nesting one of the state implementations (options will be described later). Each component becomes a part of the page or top-level component, which executes component function asynchronously and gets a state future object. In that way your components are executing in a non-blocking way. Pages are just top-level components, where you can configure rendering and page related stuff. Stateful components are pretty similar to stateless ones, but they are actually implementing marshal/unmarshal interface instead of mocking it. You have multiple state options to choose from: universal or server. Universal state is a state, that can be marshalled and unmarshalled both on server and client. It's a common state option without functionality limitations. On the other hand, the whole state must be sent and received, which applies some limitations on the state size. Server state can be marshalled and unmarshalled only on server. It's a good option for components, that are not supposed to be updated on client side (f.e. no inputs). Also, it's a good option for components with lots of state data. Sometimes you may want to pass some arguments to the component. It's easy to do with wrapping component with additional function. You have an access to the context inside the component. It includes request and response objects, as well as some other useful stuff like store. This library doesn't provide you with routing out of the box. You can use any router you want, built-in one is not a bad option for basic needs. Rendering might be tricky, but we're trying to make it as simple as possible. By default, we're using `html/template` as a rendering engine. It's a well-known built-in package, so you don't have to learn anything new. Out of the box we're parsing all templates in root directory with `*.html` glob. You can change this behavior with `TEMPLATE_GLOB` global variable. Don't rely on file names while working with template names, use `define` entry for each your component. To provide your components with ability to be rendered, you have to do some basic steps. First, you have to nest one of the rendering implementations into your component state (f.e. `rendering.Template`). You can customize rendering with providing values to the rendering implementation. If you need to modify these values for the entire project, we recommend looking at the global settings or creating a builder function for rendering object. By default, render handler will use a component name as a template name. So, you have to define a template with the same name as your component (not the filename, but "define" entry). That's enough to be rendered by `rendering.Handler`. For rendering a nested component, use built-in `template` function. Provide a resolved future object as a template argument in this way. Nested components are not obligated to have rendering implementation if you're using them in this way. As an alternative, you can nest rendering implementation (e.g. `rendering.Template`) into your nested component. In this way you can use `render` function to simplify your code. Please, don't use this approach heavily now, as it affects rendering performance. HTMX is a frontend library, that allows you to update your page layout dynamically. It perfectly fits into kyoto, which focuses on components and server side rendering. Thanks to the component structure, there is no need to define separate rendering logic specially for HTMX. Please, check https://htmx.org/docs/#installing for installation instructions. In addition to this, you must register HTMX handlers for your dynamic components. This is a basic example of HTMX usage. Please, check https://htmx.org/docs/ for more details. In this example we're defining a form component, that is updating itself on submit. And this is how you can define a component, that will handle this request. Sometimes it might be useful to have a component state, which will persist between requests and will be stored without any actual usage in the client side presentation. This function injects a hidden input field with a serialized state. Let's check how it works on the server side. As a result, we have a component with a persistent state between requests.
Extensible Go library for creating fast, SSR-first frontend avoiding vanilla templating downsides. Creating asynchronous and dynamic layout parts is a complex problem for larger projects using `html/template`. This library tries to simplify overall setup and process. Let's go straight into a simple example. Then, we will dig into details, step by step, how it works. Kyoto provides a set of simple net/http handlers, handler builders and function wrappers to provide serving, pages rendering, component actions, etc. Anyway, this is not an ultimative solution for any case. If you ever need to wrap/extend existing functionality, library encourages this. See functions inside of nethttp.go file for details and advanced usage. Example: Kyoto provides a way to define components. It's a very common approach for modern libraries to manage frontend parts. In kyoto each component is a context receiver, which returns it's state. Each component becomes a part of the page or top-level component, which executes component asynchronously and gets a state future object. In that way your components are executing in a non-blocking way. Pages are just top-level components, where you can configure rendering and page related stuff. Example: As an option, you can wrap component with another function to accept additional paramenters from top-level page/component. Example: Kyoto provides a context, which holds common objects like http.ResponseWriter, *http.Request, etc. See kyoto.Context for details. Example: Kyoto provides a set of parameters and functions to provide a comfortable template building process. You can configure template building parameters with kyoto.TemplateConf configuration. See template.go for available functions and kyoto.TemplateConfiguration for configuration details. Example: Kyoto provides a way to simplify building dynamic UIs. For this purpose it has a feature named actions. Logic is pretty simple. Client calls an action (sends a request to the server). Action is executing on server side and server is sending updated component markup to the client which will be morphed into DOM. That's it. To use actions, you need to go through a few steps. You'll need to include a client into page (JS functions for communication) and register an actions handler for a needed component. Let's start from including a client. Then, let's register an actions handler for a needed component. That's all! Now we ready to use actions to provide a dynamic UI. Example: In this example you can see provided modifications to the quick start example. First, we've added a state and name into our components' markup. In this way we are saving our components' state between actions and find a component root. Unfortunately, we have to manually provide a component name for now, we haven't found a way to provide it dynamically. Second, we've added a reload button with onclick function call. We're using a function Action provided by a client. Action triggering will be described in details later. Third, we've added an action handler inside of our component. This handler will be executed when a client calls an action with a corresponding name. It's highly recommended to keep components' state as small as possible. It will be transmitted on each action call. Kyoto have multiple ways to trigger actions. Now we will check them one by one. This is the simplest way to trigger an action. It's just a function call with a referer (usually 'this', f.e. button) as a first argument (used to determine root), action name as a second argument and arguments as a rest. Arguments must to be JSON serializable. It's possible to trigger an action of another component. If you want to call an action of parent component, use $ prefix in action name. If you want to call an action of component by id, use <id:action> as an action name. This is a specific action which is triggered when a form is submitted. Usually called in onsubmit="..." attribute of a form. You'll need to implement 'Submit' action to handle this trigger. This is a special HTML attribute which will trigger an action on page load. This may be useful for components' lazy loading. With this special HTML attributes you can trigger an action with interval. Useful for components that must to be updated over time (f.e. charts, stats, etc). You can use this trigger with ssa:poll and ssa:poll.interval HTML attributes. This one attribute allows you to trigger an action when an element is visible on the screen. May be useful for lazy loading. Kyoto provides a way to control action flow. For now, it's possible to control display style on component call and push multiple UI updates to the client during a single action. Because kyoto makes a roundtrip to the server every time an action is triggered on the page, there are cases where the page may not react immediately to a user event (like a click). That's why the library provides a way to easily control display attributes on action call. You can use this HTML attribute to control display during action call. At the end of an action the layout will be restored. A small note. Don't forget to set a default display for loading elements like spinners and loaders. You can push multiple component UI updates during a single action call. Just call kyoto.ActionFlush(ctx, state) to initiate an update. Kyoto provides a way to control action rendering. Now there is at least 2 rendering options after an action call: morph (default) and replace. Morph will try to morph received markup to the current one with morphdom library. In case of an error, or explicit "replace" mode, markup will be replaced with x.outerHTML = '...'.
Package fault provides standard http middleware for fault injection in go. Use the fault package to inject faults into the http request path of your service. Faults work by modifying and/or delaying your service's http responses. Place the Fault middleware high enough in the chain that it can act quickly, but after any other middlewares that should complete before fault injection (auth, redirects, etc...). The type and severity of injected faults is controlled by options passed to NewFault(Injector, Options). NewFault must be passed an Injector, which is an interface that holds the actual fault injection code in Injector.Handler. The Fault wraps Injector.Handler in another Fault.Handler that applies generic Fault logic (such as what % of requests to run the Injector on) to the Injector. Make sure you use the NewFault() and NewTypeInjector() constructors to create valid Faults and Injectors. There are three main Injectors provided by the fault package: Use fault.RejectInjector to immediately return an empty response. For example, a curl for a rejected response will produce: Use fault.ErrorInjector to immediately return a valid http status code of your choosing along with the standard HTTP response body for that code. For example, you can return a 200, 301, 418, 500, or any other valid status code to test how your clients respond to different statuses. Pass the WithStatusText() option to customize the response text. Use fault.SlowInjector to wait a configured time.Duration before proceeding with the request. For example, you can use the SlowInjector to add a 10ms delay to your requests. Use fault.RandomInjector to randomly choose one of the above faults to inject. Pass a list of Injector to fault.NewRandomInjector and when RandomInjector is evaluated it will randomly run one of the injectors that you passed. It is easy to combine any of the Injectors into a chained action. There are two ways you might want to combine Injectors. First, you can create separate Faults for each Injector that are sequential but independent of each other. For example, you can chain Faults such that 1% of requests will return a 500 error and another 1% of requests will be rejected. Second, you might want to combine Faults such that 1% of requests will be slowed for 10ms and then rejected. You want these Faults to depend on each other. For this use the special ChainInjector, which consolidates any number of Injectors into a single Injector that runs each of the provided Injectors sequentially. When you add the ChainInjector to a Fault the entire chain will always execute together. The NewFault() constructor has WithPathBlocklist() and WithPathAllowlist() options. Any path you include in the PathBlocklist will never have faults run against it. With PathAllowlist, if you provide a non-empty list then faults will not be run against any paths except those specified in PathAllowlist. The PathBlocklist take priority over the PathAllowlist, a path in both lists will never have a fault run against it. The paths that you include must match exactly the path in req.URL.Path, including leading and trailing slashes. Simmilarly, you may also use WithHeaderBlocklist() and WithHeaderAllowlist() to block or allow faults based on a map of header keys to values. These lists behave in the same way as the path allowlists and blocklists except that they operate on headers. Header equality is determined using http.Header.Get(key) which automatically canonicalizes your keys and does not support multi-value headers. Keep these limitations in mind when working with header allowlists and blocklists. Specifying very large lists of paths or headers may cause memory or performance issues. If you're running into these problems you should instead consider using your http router to enable the middleware on only a subset of your routes. The fault package provides an Injector interface and you can satisfy that interface to provide your own Injector. Use custom injectors to add additional logic to the package-provided injectors or to create your own completely new Injector that can still be managed by a Fault. The package provides a Reporter interface that can be added to Faults and Injectors using the WithReporter option. A Reporter will receive events when the state of the Injector changes. For example, Reporter.Report(InjectorName, StateStarted) is run at the beginning of all Injectors. The Reporter is meant to be provided by the consumer of the package and integrate with services like stats and logging. The default Reporter throws away all events. By default all randomness is seeded with defaultRandSeed(1), the same default as math/rand. This helps you reproduce any errors you see when running an Injector. If you prefer, you can also customize the seed passing WithRandSeed() to NewFault and NewRandomInjector. Some Injectors support customizing the functions they use to run their injections. You can take advantage of these options to add your own logic to an existing Injector instead of creating your own. For example, modify the SlowInjector function to slow in a rancom distribution instead of for a fixed duration. Be careful when you use these options that your return values fall within the same range of values expected by the default functions to avoid panics or other undesirable begavior. Customize the function a Fault uses to determine participation (default: rand.Float32) by passing WithRandFloat32Func() to NewFault(). Customize the function a RandomInjector uses to choose which injector to run (default: rand.Intn) by passing WithRandIntFunc() to NewRandomInjector(). Customize the function a SlowInjector uses to wait (default: time.Sleep) by passing WithSlowFunc() to NewSlowInjector(). Configuration for the fault package is done through options passed to NewFault and NewInjector. Once a Fault is created its enabled state and participation percentage can be updated with SetEnabled() and SetParticipation(). There is no other way to manage configuration for the package. It is up to the user of the fault package to manage how the options are generated. Common options are feature flags, environment variables, or code changes in deploys. Example is a package-level documentation example.
Package aetools helps writting, testing and analysing Google App Engine applications. The aetools package implements a simple API to export the entity data from Datastore as a JSON stream, as well as load a JSON stream back into the Datastore. This can be used as a simple way to express state into a unit test, to backup a development environment state that can be shared with team members, or to make quick batch changes to data offline, like setting up configuration entities via Remote API. The goal is to provide both an API and a set of executable tools that uses that API, allowing for maximum flexibility. The functions Load, LoadJSON, Dump and DumpJSON operate using JSON data that represents datastore entities. Each entity is mapped to a JSON Object, where each entity property name is an Object atribute, and each property value is the corresponding Object atribute value. The property value is encoded using a JSON primitive, when possible. When the primitives are not sufficient to represent the property value, a JSON Object with the attributes "type" and "value" is used. The "type" attribute is a Datastore type, and value is a json-primitive serialization of that value. For instance, Blobs are encoded as a base64 JSON string, and time.Time values are encoded using the time.RFC3339 layout, also as strings. Datastore Keys are aways encoded as a JSON Array that represents the Key Path, including ancestors, but without the application ID. This is done to allow the entity key to be more readable and to be application independent. Currently, they don't support namespaces. Multiple properties are represented as a JSON Array of values described above. Unindexed properties are aways JSON objects with the "indexed" attribute set to false. This format is intended to make use of the JSON types as much as possible, so an entity can be easily represented as a text file, suitable for read or SCM checkin. The exported data format can also be used as an alternative way to export from Datastore, and then load the results right into other service, such as Google BigQuery or MongoDB. The package aetools/bundle contains a sample webapp to help you manage and stream datastore entities into BigQuery. The bundle uses the aetools/bigquerysync functions to infer an usefull schema from datastore statistics, and sync your entity data into BigQuery. The command aetools/remote_api is a Remote API client that exposes the Load and Dump functions to make backup and restore of development environment state quick and easy. This tool can also help setting up Q.A. or Production apps, but should be used with care.
Package streams is an interface for using multiplexed transports protocols in a way that allows swapping between protocols without changing the higher level implementation. The `StreamProvider` interface is intended to abstract the underlying protocol in a way that is centered around creating and managing the individually multiplexed streams. Streams may either be created locally or remotely. In the case of remotely created streams, a listener must be used to accept new streams. The `Stream` interface allows sending and receiving bytes as easy as any io.ReadWriteCloser. In addition to reading and writing, the interface allows for retrieving the create headers and fully resetting the stream. The `Close` method is used to signal that no more writes will occur locally on the stream. This puts the stream in a half-closed state, still allowing for remote writes and local reads. Once the remote side calls `Close`, the stream will be fully closed, causing any future reads to return `io.EOF`. The `Reset` method is used to force the stream into a fully closed state. This should only be called in error cases which do not allow for any further action to occur on the stream. Forcing the stream into a fully close state may cause remote writes to fail, which should be handled by the remote. The `Listener` interface is used to retrieve remotely created streams for local use. The `Accept` method will return the new stream will require the application to manage the local lifecycle of that stream. If the retrieved stream is invalid, possibly due to a bad header configuration, the application should call `Reset` on the stream, indicating to the remote side this stream will not be used.
Package ssp implements the SQRL server-side protocol (SSP). The SqrlSspApi is a stateful server object that manages SQRL identities. The /cli.sqrl exposed at Cli is the only endpoint that is required to operate in conjunction with the SQRL client. This endpoint is required to be served over https. While it's possible that this code can be run within a web server that terminates TLS itself, the expectation is that it is served from behind a load balancer or reverse proxy. While I attempt to reconstruct the host and paths from the request and standard forwarding headers, this can be unreliable and it's best to confgure the HostOverride and RootPath
CDK - Curses Development Kit The Curses Development Kit is the low-level compliment to the higher-level Curses Tool Kit. CDK is based primarily upon the TCell codebase, however, it is a hard-fork with many API-breaking changes. Some of the more salient changes are as follows: All CDK applications require some form of `Window` implementation in order to function. One can use the build-in `cdk.CWindow` type to construct a basic `Window` object and tie into it's signals in order to render to the canvas and handle events. For this example however, a more formal approach is taken. Starting out with a very slim definition of our custom `Window`, all that's necessary is the embed the concrete `cdk.CWindow` type and proceed with overriding various methods. The `Init` method is not necessary to overload, however, this is a good spot to do any UI initializations or the like. For this demo, the boilerplate minimum is given as an example to start from. The next method implemented is the `Draw` method. This method receives a pre-configured Canvas object, set to the available size of the `Display`. Within this method, the application needs to process as little "work" as possible and focus primarily on just rendering the content upon the canvas. Let's walk through each line of the `Draw` method. This line uses the built-in logging facilities to log an "info" message that the `Draw` method was invoked and let's us know some sort of human-readable description of the canvas (resembles JSON text but isn't really JSON). The advantage to using these built-in logging facilities is that the log entry itself will be prefixed with some extra metadata identifying the particular object instance with a bit of text in the format of "typeName-ID" where typeName is the object's CDK-type and the ID is an integer (marking the unique instance). Within CDK, there is a concept of `Theme`, which really is just a collection of useful purpose-driven `Style`s. One can set the default theme for the running CDK system, however the stock state is either a monochrome base theme or a colorized variant. Some of the rendering functions require `Style`s or `Theme`s passed as arguments and so we're getting that here for later use. Simply getting a `Rectangle` primitive with it's `W`idth and `H`eight values set according to the size of the canvas' internal buffer. `Rectangle` is a CDK primitive which has just two fields: `W` and `H`. Most places where spacial bounds are necessary, these primitives are used (such as the concept of a box `size` for painting upon a canvas). This is the first actual draw command. In this case, the `Box` method is configured to draw a box on the screen, starting at a position of 0,0 (top left corner), taking up the full volume of the canvas, with a border (first boolean `true` argument), ensuring to fill the entire area with the filler rune and style within a given theme, which is the last argument to the `Box` method. On a color-supporting terminal, this will paint a navy-blue box over the entire terminal screen. These few lines of code are merely concatenating a string of `Tango` markup that includes use of `<b></b>`, `<u></u>`, `<i></i>`, and `<span></span>` tags. All colors have fallback versions and are typically safe even for monochrome terminal sessions. This sets up a variable holding a `Point2I` instance configured for 1/4 of the width into the screen (from the left) and halfway minus one of the height into the screen (from the top). `Point2I` is a CDK primitive which has just two fields: `X` and `Y`. Most places where coordinates are necessary, these primitives are used (such as the concept of an `origin` point for painting upon a canvas). This sets up a variable holding a `Rectangle` configured to be half the size of the canvas itself. This last command within the `Draw` method paints the textual-content prepared earlier onto the canvas provided, center-justified, wrapping on word boundaries, using the default `Normal` theme, specifying that the content is in fact to be parsed as `Tango` markup and finally the content itself. The result of this drawing process should be a navy-blue screen, with a border, and three lines of text centered neatly. The three lines of text should be marked up with bold, italics, underlines and colorization. The last line of text should be telling the current time and date at the time of rendering. The `ProcessEvent` method is the main event handler. Whenever a new event is received by a CDK `Display`, it is passed on to the active `Window` and in this demonstration, all that's happening is a log entry is being made which mentions the event received. When implementing your own `ProcessEvent` method, if the `Display` should repaint the screen for example, one would make two calls to methods on the `DisplayManager`: CDK is a multi-threaded framework and the various `Request*()` methods on the `DisplayManager` are used to funnel requests along the right channels in order to first render the canvas (via `Draw` calls on the active `Window`) and then follow that up with the running `Display` painting itself from the canvas modified in the `Draw` process. The other complete list of request methods is as follows: This concludes the `CdkDemoWindow` type implementation. Now on to using it! The `main()` function within the `_demos/cdk-demo.go` sources is deceptively simple to implement. The bulk of the code is constructing a new CDK `App` instance. This object is a wrapper around the `github.com/urfave/cli/v2` CLI package, providing a tidy interface to managing CLI arguments, help documentation and so on. In this example, the `App` is configured with a bunch of metadata for: the program's name "cdk-demo", a simply usage summary, the current version number, an internally-used tag, a title for the main window and the display is to use the `/dev/tty` (default) terminal device. Beyond the metadata, the final argument is an initialization function. This function receives a fully instantiated and running `Display` instance and it is expected that the application instantiates it's `Window` and sets it as the active window for the given `Display`. In addition to that is one final call to `AddTimeout`. This call will trigger the given `func() cdk.EventFlag` once, after a second. Because the `func()` implemented here in this demonstration returns the `cdk.EVENT_PASS` flag it will be continually called once per second. For this demonstration, this implementation simply requests a draw and show cycle which will cause the screen to be repainted with the current date and time every second the demo application is running. The final bit of code in this CDK demonstration simply passes the arguments provided by the end-user on the command-line in a call to the `App`'s `Run()` method. This will cause the `DisplayManager`, `Display` and other systems to instantiate and begin processing events and render cycles.
Package mysqldriver is a GC optimized MySQL driver DB struct manages pool of connections to MySQL. Connection itself isn't thread-safe, so it should be obtained per every go-routine. It's important to return a connection back to the pool when it's not needed for further reuse. mysqldriver reads data from the DB in a sequential order which means the whole result set of first query must be read before executing another one. Number of read column's values and their types must match with the number of columns in a query. When there is no need to read the whole result set, for instance when error occurred during parsing data, connection must be closed to prevent further reuse as it's in invalid state.
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. 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 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/joshuaalewis/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 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 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 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 nifcloud.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/nifcloud/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/nifcloud/#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 (~/.nifcloud/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/nifcloud/credentials The SDK has support for the shared configuration file (~/.nifcloud/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/nifcloud/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/nifcloud/#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.
Extensible Go library for creating fast, SSR-first frontend avoiding vanilla templating downsides. Creating asynchronous and dynamic layout parts is a complex problem for larger projects using `html/template`. Library tries to simplify this process. Let's go straight into a simple example. Then, we will dig into details, step by step, how it works. Kyoto provides a simple net/http handlers and function wrappers to handle pages rendering and serving. See functions inside of nethttp.go file for details and advanced usage. Example: Kyoto provides a way to define components. It's a very common approach for modern libraries to manage frontend parts. In kyoto each component is a context receiver, which returns it's state. Each component becomes a part of the page or top-level component, which executes component asynchronously and gets a state future object. In that way your components are executing in a non-blocking way. Pages are just top-level components, where you can configure rendering and page related stuff. Example: As an option, you can wrap component with another function to accept additional paramenters from top-level page/component. Example: Kyoto provides a context, which holds common objects like http.ResponseWriter, *http.Request, etc. See kyoto.Context for details. Example: Kyoto provides a set of parameters and functions to provide a comfortable template building process. You can configure template building parameters with kyoto.TemplateConf configuration. See template.go for available functions and kyoto.TemplateConfiguration for configuration details. Example: Kyoto provides a way to simplify building dynamic UIs. For this purpose it has a feature named actions. Logic is pretty simple. Client calls an action (sends a request to the server). Action is executing on server side and server is sending updated component markup to the client which will be morphed into DOM. That's it. To use actions, you need to go through a few steps. You'll need to include a client into page (JS functions for communication) and register an actions handler for a needed component. Let's start from including a client. Then, let's register an actions handler for a needed component. That's all! Now we ready to use actions to provide a dynamic UI. Example: In this example you can see provided modifications to the quick start example. First, we've added a state and name into our components' markup. In this way we are saving our components' state between actions and find a component root. Unfortunately, we have to manually provide a component name for now, we haven't found a way to provide it dynamically. Second, we've added a reload button with onclick function call. We're using a function Action provided by a client. Action triggering will be described in details later. Third, we've added an action handler inside of our component. This handler will be executed when a client calls an action with a corresponding name. It's highly recommended to keep components' state as small as possible. It will be transmitted on each action call. Kyoto have multiple ways to trigger actions. Now we will check them one by one. This is the simplest way to trigger an action. It's just a function call with a referer (usually 'this', f.e. button) as a first argument (used to determine root), action name as a second argument and arguments as a rest. Arguments must to be JSON serializable. It's possible to trigger an action of another component. If you want to call an action of parent component, use $ prefix in action name. If you want to call an action of component by id, use <id:action> as an action name. This is a specific action which is triggered when a form is submitted. Usually called in onsubmit="..." attribute of a form. You'll need to implement 'Submit' action to handle this trigger. This is a special HTML attribute which will trigger an action on page load. This may be useful for components' lazy loading. With this special HTML attributes you can trigger an action with interval. Useful for components that must to be updated over time (f.e. charts, stats, etc). You can use this trigger with ssa:poll and ssa:poll.interval HTML attributes. This one attribute allows you to trigger an action when an element is visible on the screen. May be useful for lazy loading. Kyoto provides a way to control action flow. For now, it's possible to control display style on component call and push multiple UI updates to the client during a single action. Because kyoto makes a roundtrip to the server every time an action is triggered on the page, there are cases where the page may not react immediately to a user event (like a click). That's why the library provides a way to easily control display attributes on action call. You can use this HTML attribute to control display during action call. At the end of an action the layout will be restored. A small note. Don't forget to set a default display for loading elements like spinners and loaders. You can push multiple component UI updates during a single action call. Just call kyoto.ActionFlush(ctx, state) to initiate an update. Kyoto provides a way to control action rendering. Now there is at least 2 rendering options after an action call: morph (default) and replace. Morph will try to morph received markup to the current one with morphdom library. In case of an error, or explicit "replace" mode, markup will be replaced with x.outerHTML = '...'.
Creates and manages a connetion environment that allows the user to establish TCP connections (outgoing) and listens/accepts connection requests from remote processes. The connection manager object is created with NewManager which accepts a listen port and a channel on which Sess_data objects are written. The listener is invoked and when a connection is accepted a connection reader is started and a ST_NEW Sess_data object is written on the user's channel. The reader sends all data via the channel (ST_DATA) and if the session is disconnected a Sess_data object with the ST_DISC state is written and the connection is cleaned up (no need for user to invoke the Close function in a disconnect case. When a user establishes a connection the remote IP address and a session id (name) are supplied along with a communication channel. The channel may be the same channel supplied when the connection manager object was created or it may be a different channel. Data received from either a UDP listener, or on a connected TCP session is bundled into a Sess_data struct and placed onto the appropriate channel. The struct contains, in addition to the received buffer, the ID of the session that can be used on a generic Write command to, the current state of the session (ST_ constants), and a string indicating some useful (humanised) data about the session.
Package eclcloud provides interface to Enterprise Cloud. 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 Enterprise Cloud. Use your Enterprise Cloud credentials to create a Provider client. The IdentityEndpoint is typically referred 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 may also use the ecl.AuthOptionsFromEnv() helper function. This function reads in standard environment variables frequently found in an Enterprise Cloud `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 Enterprise Cloud 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.
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 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 nifcloud.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/nifcloud/session/ See the Config type in the aws package for more information on configuration options. https://docs.aws.amazon.com/sdk-for-go/api/nifcloud/#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 (~/.nifcloud/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/nifcloud/credentials The SDK has support for the shared configuration file (~/.nifcloud/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/nifcloud/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/nifcloud/#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 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. • 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 sfn provides the client and types for making API requests to AWS Step Functions. AWS Step Functions is a service that lets you coordinate the components of distributed applications and microservices using visual workflows. You can use Step Functions to build applications from individual components, each of which performs a discrete function, or task, allowing you to scale and change applications quickly. Step Functions provides a console that helps visualize the components of your application as a series of steps. Step Functions automatically triggers and tracks each step, and retries steps when there are errors, so your application executes predictably and in the right order every time. Step Functions logs the state of each step, so you can quickly diagnose and debug any issues. Step Functions manages operations and underlying infrastructure to ensure your application is available at any scale. You can run tasks on AWS, your own servers, or any system that has access to AWS. You can access and use Step Functions using the console, the AWS SDKs, or an HTTP API. For more information about Step Functions, see the AWS Step Functions Developer Guide (http://docs.aws.amazon.com/step-functions/latest/dg/welcome.html). See https://docs.aws.amazon.com/goto/WebAPI/states-2016-11-23 for more information on this service. See sfn package documentation for more information. https://docs.aws.amazon.com/sdk-for-go/api/service/sfn/ To AWS Step Functions 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 AWS Step Functions client SFN for more information on creating client for this service. https://docs.aws.amazon.com/sdk-for-go/api/service/sfn/#New