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
Supports circular $ref pointers (see notes below)
Multiple $ref pointers to the same object are resolved to the same object instance

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)`

swagger (required) - string or object
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.

If you pass an object instead of a string, then the parsing step will be skipped, but the object will still be validated, resolved, and dereferenced just like normal.
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.
`dereference$Refs`	bool	true	Determines whether `$ref` pointers in the Swagger API will be replaced with their resolved values. Different `$ref` pointers that resolve to the same object will be replaced with the same object instance. Setting this option to `false` will leave the `$ref` pointers in the Swagger API, but you can still access the resolved values using the metadata object.
`resolve$Refs`	bool	true	Determines whether `$ref` pointers will be resolved. Setting this option to `false` effectively disables `dereference$Refs` as well. The difference is that the metadata object won't be populated either.
`resolveExternal$Refs`	bool	true	Determines whether `$ref` pointers will be resolved if they point to external files or URLs. Internal `$ref` pointers will still be resolved and dereferenced.
`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 `null` if an error occurred
`metadata`	object	This parameter provides extra information about the parsing operation. It is always provided, even if there's an error.

Metadata

The metadata parameter is an object with the following properties:

Property	Type	Description
`baseDir`	string	The base directory used to resolve any external $ref pointers. If you passed a file path/URL to the `parse` method, then the `baseDir` is the directory of that file. If you passed an object, then `baseDir` is set to `process.cwd()` in Node, or the URL of the current page in browsers.
`files`	array of strings	The full paths of all files that were parsed. This only includes local files, not URLs. If `Parser.parse()` was called with a local file path, then it will be the first item in this array.
`urls`	array of URL objects	The URLs that were parsed. If `Parser.parse()` was called with a URL, then it will be the first item in this array.
`$refs`	object	A map of all the $ref pointers that were resolved, and the objects they resolved to. If an error occurs while resolving a reference, then this object will still contain the $refs that were successfully parsed up to that point.

Circular $Refs

Swagger files can contain circular $ref pointers, and Swagger-Parser will correctly parse them, resolve their values, and validate them against the Swagger schema. However, Swagger-Parser does not dereference circular references because this can easily cause stack overflows when the Swagger object is serialized, as well as other, more subtle bugs.

If your Swagger API includes circular references, then the callback will receive a ReferenceError to alert you that the Swagger object was not fully dereferenced. However, you can choose to ignore this error and use the api parameter anyway. All non-circular $ref pointers in the Swagger object will still be resolved and dereferenced like always. Circular $ref pointers will not be dereferenced, but they will be resolved, so you can access their resolved values in metadata.$refs.

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

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).

License

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

xrysanthos / swagger-parser