swagger-parser

What is swagger-parser?

swagger-parser is a powerful npm package that allows you to parse, validate, and dereference Swagger (OpenAPI) definitions. It helps in ensuring that your API definitions are correct and can be used to resolve $ref pointers to simplify the API documentation.

What are swagger-parser's main functionalities?

Parse

This feature allows you to parse a Swagger (OpenAPI) definition file. The code sample demonstrates how to parse a Swagger file and log the API name and version.

const SwaggerParser = require('swagger-parser');

SwaggerParser.parse('path/to/your/swagger.yaml')
  .then(api => {
    console.log('API name: %s, Version: %s', api.info.title, api.info.version);
  })
  .catch(err => {
    console.error(err);
  });

Validate

This feature allows you to validate a Swagger (OpenAPI) definition file. The code sample demonstrates how to validate a Swagger file and log whether the API is valid or not.

const SwaggerParser = require('swagger-parser');

SwaggerParser.validate('path/to/your/swagger.yaml')
  .then(api => {
    console.log('API is valid:', api);
  })
  .catch(err => {
    console.error('API is invalid:', err);
  });

Dereference

This feature allows you to dereference $ref pointers in a Swagger (OpenAPI) definition file. The code sample demonstrates how to dereference a Swagger file and log the dereferenced API.

const SwaggerParser = require('swagger-parser');

SwaggerParser.dereference('path/to/your/swagger.yaml')
  .then(api => {
    console.log('Dereferenced API:', api);
  })
  .catch(err => {
    console.error(err);
  });

Bundle

This feature allows you to bundle all external $ref pointers into a single file. The code sample demonstrates how to bundle a Swagger file and log the bundled API.

const SwaggerParser = require('swagger-parser');

SwaggerParser.bundle('path/to/your/swagger.yaml')
  .then(api => {
    console.log('Bundled API:', api);
  })
  .catch(err => {
    console.error(err);
  });

Other packages similar to swagger-parser

openapi-schema-validator

openapi-schema-validator is a package that validates OpenAPI 3.0 schemas. It focuses on schema validation and does not provide parsing or dereferencing functionalities like swagger-parser.

swagger-jsdoc

swagger-jsdoc is a package that generates Swagger (OpenAPI) definitions from JSDoc comments in your code. It is more focused on generating documentation from code comments rather than parsing and validating existing Swagger files.

swagger-client

swagger-client is a package that provides a JavaScript client for interacting with Swagger (OpenAPI) APIs. It includes functionalities for making API requests and handling responses, but it does not focus on parsing or validating Swagger definitions.

README

Swagger-Parser

Parses, validates, and dereferences JSON/YAML Swagger specs in Node and browsers

Features

• Parses Swagger specs in JSON or YAML format
• Validates against the official Swagger 2.0 schema
• Dereferences all $ref pointers, including pointers to external files and URLs
• Asynchronously downloads and caches external files and URLs
• Tested in Node.js and all major web browsers on Windows, Mac, and Linux
• Supports nested $ref pointers, even in external files and URLs
• Multiple $ref pointers to the same definition are resolved to the same object instance, thus maintaining strict reference equality

Basic Example

swagger.parser.parse("swagger.yaml", function(err, api, metadata) {
  if (!err) {
    console.log("API name: %s, Version: %s", api.info.title, api.info.version);
  }
});

The api parameter that's passed to the callback function is the parsed, validated, and dereferenced Swagger object.

Installation and Use

Node

npm install swagger-parser

Then add this to your Node script:

var parser = require("swagger-parser");
parser.parse('swagger.yaml', function(err, api, metadata) { ... });

Bower

bower install swagger-parser

Then add this to your HTML page:

<script src="bower_components/swagger-parser/dist/swagger-parser.js"></script>
<script>
    swagger.parser.parse('http://mysite.com/swagger.yaml', function(err, api, metadata) { ... });
</script>

AMD (Require.js)

Just add swagger-parser to your AMD module's dependencies, or require("swagger-parser") explicitly.

define("myModule", ["swagger-parser"], function(parser) {
    parser.parse('http://mysite.com/swagger.yaml', function(err, api, metadata) { ... });
});

The API

Parser.parse(swaggerPath, [options], callback)

• swaggerPath (required) - string
  The file path or URL of your Swagger file. Relative paths are allowed. In Node, the path is relative to process.cwd(). In the browser, it's relative to the URL of the page.

• options (optional) - object
  An object containing one or more parsing options. See options below.

• callback (required) - function(err, api, metadata)
  Called after the parsing is finished, or when an error occurs. See callback below for details.

Options

Property	Type	Default	Description
parseYaml	bool	true	Determines whether the parser will allow Swagger specs in YAML format. If set to false, then only JSON will be allowed.
resolve$Refs	bool	true	Determines whether $ref pointers will be resolved. If set to false, then the resulting Swagger object will contain Reference objects instead of the objects they reference.
resolveExternal$Refs	bool	true	Determines whether $ref pointers will be resolved if they point to external files or URLs. If set to false then the resulting Swagger object will contain Reference objects for external pointers instead of the objects they reference.
validateSchema	bool	true	Determines whether your API will be validated against the official Swagger schema. If set to false, then the resulting Swagger object may be missing properties, have properties of the wrong data type, etc.

Callback

Parameter	Type	Description
err	Error	null unless an error occurred.
api	Swagger object	The complete Swagger API object. Or undefined if an error occurred
metadata	object	This parameter can usually be ignored. It provides useful information about the parsing operation itself.

The metadata parameter is an object with the following properties:

Property	Type	Description
baseDir	string	The directory of the main Swagger file, which is the base directory used to resolve any external $ref pointers.
files	array of strings	The full paths of all files that were parsed. This only includes local files, not URLs. If Parser.parse() was called with a local file path, then it will be the first item in this array.
urls	array of URL objects	The URLs that were parsed. If Parser.parse() was called with a URL, then it will be the first item in this array.
$refs	object	A map of all the $ref pointers that were resolved, and the objects they resolved to.

Contributing

I welcome any contributions, enhancements, and bug-fixes. File an issue on GitHub and submit a pull request. Use JSHint to make sure your code passes muster. (see .jshintrc).

Here are some things currently on the to-do list:

• Circular $ref pointers - Circular $ref pointers are a bit of an edge case, but it would be nice to support them anyway. Currently, something like this won't work:

person:
  properties:
    name:
      type: string
    spouse:
      type:
        $ref: person   # circular reference

License

Swagger-Parser is 100% free and open-source, under the MIT license. Use it however you want.