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Jan Henning Thorsen


Mojolicious::Plugin::OpenAPI - OpenAPI / Swagger plugin for Mojolicious


  use Mojolicious::Lite;

  # Will be moved under "basePath", resulting in "POST /api/echo"
  post "/echo" => sub {

    # Validate input request or return an error document
    my $c = shift->openapi->valid_input or return;

    # Generate some data
    my $data = {body => $c->validation->param("body")};

    # Validate the output response and render it to the user agent
    # using a custom "openapi" handler.
    $c->render(openapi => $data);
  }, "echo";

  # Load specification and start web server
  plugin OpenAPI => {url => "data:///api.json"};

  @@ api.json
    "swagger" : "2.0",
    "info" : { "version": "0.8", "title" : "Pets" },
    "schemes" : [ "http" ],
    "basePath" : "/api",
    "paths" : {
      "/echo" : {
        "post" : {
          "x-mojo-name" : "echo",
          "parameters" : [
            { "in": "body", "name": "body", "schema": { "type" : "object" } }
          "responses" : {
            "200": {
              "description": "Echo response",
              "schema": { "type": "object" }

See Mojolicious::Plugin::OpenAPI::Guides::Tutorial for a tutorial on how to write a "full" app with application class and controllers.


Mojolicious::Plugin::OpenAPI is Mojolicious::Plugin that add routes and input/output validation to your Mojolicious application based on a OpenAPI (Swagger) specification.

Have a look at the "SEE ALSO" for references to more documentation, or jump right to the tutorial.

Currently v2 is very well supported, while v3 should be considered higly EXPERIMENTAL. Note that testing out v3 requires YAML::XS to be installed.

Please report in issues or open pull requests to enhance the 3.0 support.


This module adds some extra resources automatically.

Specification renderer

The specification in JSON or human rendered format can be retrieved by requesting the basePath.

The human readable format focus on making the documentation printable, so you can easily share it with third parties as a PDF. If this documentation format is too basic or has missing information, then please report in suggestions for enhancements.


  GET https://api.example.com/v1.json
  GET https://api.example.com/v1.html


Using the HTTP method "OPTIONS" will render the specification for a given path.


  OPTIONS https://api.example.com/v1/users
  OPTIONS https://api.example.com/v1/users?method=get
  OPTIONS https://api.example.com/v1/users?method=post



  $hash = $c->openapi->spec($json_pointer)
  $hash = $c->openapi->spec("/info/title")
  $hash = $c->openapi->spec;

Returns the OpenAPI specification. A JSON Pointer can be used to extract a given section of the specification. The default value of $json_pointer will be relative to the current operation. Example:

    "paths": {
      "/pets": {
        "get": {
          // This datastructure is returned by default


  $c = $c->openapi->render_spec;

Used to render the specification as either "html" or "json". Set the "stash" in Mojolicious variable "format" to change the format to render.

This helper is called by default, when accessing the "basePath" resource.

The "html" rendering needs improvement. Any help or feedback is much appreciated.


  @errors = $c->openapi->validate;

Used to validate a request. @errors holds a list of JSON::Validator::Error objects or empty list on valid input.

Note that this helper is only for customization. You probably want "openapi.valid_input" in most cases.

Validated input parameters will be copied to Mojolicious::Controller/validation, which again can be extracted by the "name" in the parameters list from the spec. Example:

  # specification:
  "parameters": [{"in": "body", "name": "whatever", "schema": {"type": "object"}}],

  # controller
  my $body = $c->validation->param("whatever");


  $c = $c->openapi->valid_input;

Returns the Mojolicious::Controller object if the input is valid or automatically render an error document if not and return false. See "SYNOPSIS" for example usage.


This plugin register a new handler called openapi. The special thing about this handler is that it will validate the data before sending it back to the user agent. Examples:

  $c->render(json => {foo => 123});    # without validation
  $c->render(openapi => {foo => 123}); # with validation

This handler will also use "renderer" to format the output data. The code below shows the default "renderer" which generates JSON data:

    OpenAPI => {
      renderer => sub {
        my ($c, $data) = @_;
        return Mojo::JSON::encode_json($data);



  $route = $self->route;

The parent Mojolicious::Routes::Route object for all the OpenAPI endpoints.


  $jv = $self->validator;

Holds a JSON::Validator::OpenAPI::Mojolicious object.



  $self = $self->register($app, \%config);
  $self = $app->plugin(OpenAPI => \%config);

Loads the OpenAPI specification, validates it and add routes to $app. It will also set up "HELPERS" and adds a before_render hook for auto-rendering of error documents. The return value is the object instance, which allow you to access the "ATTRIBUTES" after you load the plugin.

%config can have:


The OpenAPI specification does not allow "$ref" at every level, but setting this flag to a true value will ignore the $ref check.

Note that setting this attribute is discourage.


See "coerce" in JSON::Validator for possible values that coerce can take.

Default: 1


A list of response codes that will get a "$ref" pointing to "#/definitions/DefaultResponse", unless already defined in the spec. "DefaultResponse" can be altered by setting "default_response_name".

The default response code list is the following:

  400 | Bad Request           | Invalid input from client / user agent
  401 | Unauthorized          | Used by Mojolicious::Plugin::OpenAPI::Security
  404 | Not Found             | Route is not defined
  500 | Internal Server Error | Internal error or failed output validation
  501 | Not Implemented       | Route exists, but the action is not implemented

Note that more default codes might be added in the future if required by the plugin.


The name of the "definition" in the spec that will be used for "default_response_codes". The default value is "DefaultResponse". See "Default response schema" in Mojolicious::Plugin::OpenAPI::Guides::Tutorial for more details.


log_level is used when logging invalid request/response error messages.

Default: "warn".




route can be specified in case you want to have a protected API. Example:

  $app->plugin(OpenAPI => {
    route => $app->routes->under("/api")->to("user#auth"),
    url   => $app->home->rel_file("cool.api"),


Can be used to set a different schema, than the default OpenAPI 2.0 spec. Example values: "http://swagger.io/v2/schema.json", "v2" or "v3".


Name of the route that handles the "basePath" part of the specification and serves the specification. Defaults to "x-mojo-name" in the specification at the top level.


See "schema" in JSON::Validator for the different url formats that is accepted.

spec is an alias for "url", which might make more sense if your specification is written in perl, instead of JSON or YAML.


Can be used to overriden /info/version in the API specification, from the return value from the VERSION() method in version_from_class.

This will only have an effect if "version" is "0".

Defaults to the current $app.


Jan Henning Thorsen


Copyright (C) 2016, Jan Henning Thorsen

This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.