• What is grape-swagger?
• Related Projects
• Compatibility
• Swagger-Spec
• Installation
• Usage
• Configure
• Routes Configuration
• Markdown
• Response documentation
• Extensions
• Example

The grape-swagger gem provides an autogenerated documentation for your Grape API. The generated documentation is Swagger-compliant, meaning it can easily be discovered in Swagger UI. You should be able to point the petstore demo to your API.

These screenshot is based on the Hussars sample app.

• Grape
• Grape Entity
• Swagger UI

Grape-swagger generates documentation per Swagger Spec 2.0.

gem 'grape-swagger'

Please see UPGRADING when upgrading from a previous version.

Mount all your different APIs (with Grape::API superclass) on a root node. In the root class definition, include add_swagger_documentation, this sets up the system and registers the documentation on '/swagger_doc'. See example/api.rb for a simple demo.

require 'grape-swagger'

module API
  class Root < Grape::API
    format :json
    mount API::Cats
    mount API::Dogs
    mount API::Pirates
    add_swagger_documentation
  end
end

To explore your API, either download Swagger UI and set it up yourself or go to the online swagger demo and enter your localhost url documentation root in the url field (probably something in the line of http://localhost:3000/swagger_doc).

If you use the online demo, make sure your API supports foreign requests by enabling CORS in Grape, otherwise you'll see the API description, but requests on the API won't return. Use rack-cors to enable CORS.

require 'rack/cors'
use Rack::Cors do
  allow do
    origins '*'
    resource '*', headers: :any, methods: [ :get, :post, :put, :delete, :options ]
  end
end
```

Alternatively you can set CORS headers in a Grape `before` block.

```ruby
before do
  header['Access-Control-Allow-Origin'] = '*'
  header['Access-Control-Request-Method'] = '*'
end

• host
• base_path
• mount_path
• add_base_path
• add_version
• markdown
• api_version
• models
• hide_documentation_path
• info

You can pass a hash with optional configuration settings to add_swagger_documentation.

not all configuration options supported yet, but is WIP

host and base_path are also accepting a proc to evaluate.

Add basePath key to the JSON documentation, default is false.

add_swagger_documentation \
   add_base_path: true

Add version key to the JSON documentation, default is true.

add_swagger_documentation \
   add_version: false

add_swagger_documentation \
  markdown: GrapeSwagger::Markdown::KramdownAdapter.new

add_swagger_documentation \
  markdown: GrapeSwagger::Markdown::RedcarpetAdapter.new

This value is added to the authorizations key in the JSON documentation.

add_swagger_documentation \
   models: [
     TheApi::Entities::UseResponse,
     TheApi::Entities::ApiError
   ]

• Swagger Header Parameters
• Hiding an Endpoint
• Defining an endpoint as array
• Using an options hash
• Specify endpoint details
• Response documentation

desc "Return super-secret information", {
  headers: {
    "XAuthToken" => {
      description: "Valdates your identity",
      required: true
    },
    "XOptionalHeader" => {
      description: "Not really needed",
      required: false
    }
  }
}

desc 'Hide this endpoint', hidden: true

desc 'Conditionally hide this endpoint', hidden: lambda { ENV['EXPERIMENTAL'] != 'true' }

You can specify a swagger nickname to use instead of the auto generated name by adding `:nickname 'string'``` in the description of the endpoint.

desc 'Get a full list of pets', nickname: 'getAllPets'

desc 'Get a full list of pets', is_array: true

desc 'Get all kittens!', {
  hidden: true,
  is_array: true,
  nickname: 'getKittens',
  entity: Entities::Kitten, # or success
  http_codes: [[401, 'KittenBitesError', Entities::BadKitten]] # or failure
  # also explicit as hash: [{ code: 401, mssage: 'KittenBitesError', model: Entities::BadKitten }]
  produces: [ "array", "of", "mime_types" ],
  consumes: [ "array", "of", "mime_types" ]
  }
get '/kittens' do

desc 'Get all kittens!' do
  detail 'this will expose all the kittens'
end
get '/kittens' do

You can override paramType in POST|PUT methods to query, using the documentation hash.

params do
  requires :action, type: Symbol, values: [:PAUSE, :RESUME, :STOP], documentation: { param_type: 'query' }
end
post :act do
  ...
end

Use the nested: false property in the swagger option to make nested namespaces appear as standalone resources. This option can help to structure and keep the swagger schema simple.

namespace 'store/order', desc: 'Order operations within a store', swagger: { nested: false } do
  get :order_id do
  	...
  end
end

All routes that belong to this namespace (here: the GET /order_id) will then be assigned to the store_order route instead of the store resource route.

It is also possible to expose a namespace within another already exposed namespace:

namespace 'store/order', desc: 'Order operations within a store', swagger: { nested: false } do
  get :order_id do
  	...
  end
  namespace 'actions', desc: 'Order actions' do, nested: false
    get 'evaluate' do
      ...
    end
  end
end

Here, the GET /order_id appears as operation of the store_order resource and the GET /evaluate as operation of the store_orders_actions route.

Auto generated names for the standalone version of complex nested resource do not have a nice look. You can set a custom name with the name property inside the swagger option, but only if the namespace gets exposed as standalone route. The name should not contain whitespaces or any other special characters due to further issues within swagger-ui.

namespace 'store/order', desc: 'Order operations within a store', swagger: { nested: false, name: 'Store-orders' } do
  get :order_id do
  	...
  end
end

• Markdown in Detail
• Response documentation

Grape allows for an additional documentation hash to be passed to a parameter.

params do
  requires :id, type: Integer, desc: 'Coffee ID'
  requires :temperature, type: Integer, desc: 'Temperature of the coffee in celcius', documentation: { example: 72 }
end

The example parameter will populate the Swagger UI with the example value, and can be used for optional or required parameters.

Grape uses the option default to set a default value for optional parameters. This is different in that Grape will set your parameter to the provided default if the parameter is omitted, whereas the example value above will only set the value in the UI itself. This will set the Swagger defaultValue to the provided value. Note that the example value will override the Grape default value.

params do
  requires :id, type: Integer, desc: 'Coffee ID'
  optional :temperature, type: Integer, desc: 'Temperature of the coffee in celcius', default: 72
end

Add the grape-entity gem to our Gemfile.

The following example exposes statuses. And exposes statuses documentation adding :type and :desc.

module API
  module Entities
    class Status < Grape::Entity
      expose :text, documentation: { type: 'string', desc: 'Status update text.' }
      expose :links, using: Link, documentation: { type: 'link', is_array: true }
      expose :numbers, documentation: { type: 'integer', desc: 'favourite number', values: [1,2,3,4] }
    end

    class Link < Grape::Entity
      expose :href, documentation: { type: 'url' }
      expose :rel, documentation: { type: 'string'}
    end
  end

  class Statuses < Grape::API
    version 'v1'

    desc 'Statuses index',
      entity: API::Entities::Status
    get '/statuses' do
      statuses = Status.all
      type = current_user.admin? ? :full : :default
      present statuses, with: API::Entities::Status, type: type
    end

    desc 'Creates a new status',
      entity: API::Entities::Status,
      params: API::Entities::Status.documentation
    post '/statuses' do
        ...
    end
  end
end

You may safely omit type from relationships, as it can be inferred. However, if you need to specify or override it, use the full name of the class leaving out any modules named Entities or Entity.

module API
  module Entities
    class Client < Grape::Entity
      expose :name, documentation: { type: 'string', desc: 'Name' }
      expose :addresses, using: Entities::Address,
        documentation: { type: 'API::Address', desc: 'Addresses.', param_type: 'body', is_array: true }
    end

    class Address < Grape::Entity
      expose :street, documentation: { type: 'string', desc: 'Street.' }
    end
  end

  class Clients < Grape::API
    version 'v1'

    desc 'Clients index', params: Entities::Client.documentation
    get '/clients' do
      ...
    end
  end

  add_swagger_documentation models: [Entities::Client, Entities::Address]
end

Note: is_array is false by default.

module API
  module Entities
    class Client < Grape::Entity
      expose :name, documentation: { type: 'string', desc: 'Name' }
      expose :address, using: Entities::Address,
        documentation: { type: 'API::Address', desc: 'Addresses.', param_type: 'body', is_array: false }
    end

    class Address < Grape::Entity
      expose :street, documentation: { type: 'string', desc: 'Street' }
    end
  end

  class Clients < Grape::API
    version 'v1'

    desc 'Clients index', params: Entities::Client.documentation
    get '/clients' do
      ...
    end
  end

  add_swagger_documentation models: [Entities::Client, Entities::Address]
end

The grape-swagger gem allows you to add an explanation in markdown in the detail field. Which would result in proper formatted markdown in Swagger UI. Grape-swagger uses adapters for several markdown formatters. It includes adapters for kramdown (kramdown syntax) and redcarpet. The adapters are packed in the GrapeSwagger::Markdown modules. We do not include the markdown gems in our gemfile, so be sure to include or install the depended gems.

To use it, add a new instance of the adapter to the markdown options of add_swagger_documentation, such as:

add_swagger_documentation \
  markdown: GrapeSwagger::Markdown::KramdownAdapter.new(options)

and write your route details in GFM, examples could be find in details spec

If you want to use kramdown as markdown formatter, you need to add kramdown to your gemfile.

gem 'kramdown'

Configure your api documentation route with:

add_swagger_documentation \
  markdown: GrapeSwagger::Markdown::KramdownAdapter.new(options)

As alternative you can use redcarpet as formatter, you need to include redcarpet in your gemspec. If you also want to use rouge as syntax highlighter you also need to include it.

gem 'redcarpet'
gem 'rouge'

Configure your api documentation route with:

add_swagger_documentation(
  markdown: GrapeSwagger::Markdown::RedcarpetAdapter.new(render_options: { highlighter: :rouge })
)

Alternatively you can disable rouge by adding :none as highlighter option. You can add redcarpet extensions and render options trough the extenstions: and render_options: parameters.

You can also add your custom adapter for your favourite markdown formatter, as long it responds to the method markdown(text) and it formats the given text.

module API

  class FancyAdapter
   attr_reader :adapter

   def initialize(options)
    require 'superbmarkdownformatter'
    @adapter = SuperbMarkdownFormatter.new options
   end

   def markdown(text)
      @adapter.render_supreme(text)
   end
  end

  add_swagger_documentation markdown: FancyAdapter.new(no_links: true)
end

desc 'thing', http_codes: [ { code: 400, message: "Invalid parameter entry" } ]
get '/thing' do
  ...
end

desc 'thing' do
  params Entities::Something.documentation
  http_codes [ { code: 400, message: "Invalid parameter entry" } ]
end
get '/thing' do
  ...
end

get '/thing', http_codes: [
  { code: 200, message: 'Ok' },
  { code: 400, message: "Invalid parameter entry" }
] do
  ...
end

get '/thing', http_codes: [
  { code: 200, message: 'Ok' },
  { code: 422, message: "Invalid parameter entry", model: Entities::ApiError }
] do
  ...
end

If no status code is defined defaults would be taken.

The result is then something like following:

"responses": {
  "200": {
    "description": "get Horses",
    "schema": {
      "$ref": "#/definitions/Thing"
    }
  },
  "401": {
    "description": "HorsesOutError",
    "schema": {
      "$ref": "#/definitions/ApiError"
    }
  }
},

Swagger spec2.0 supports extensions on different levels, for the moment, the documentation on verb, path and definition level would be supported. The documented key would be generated from the x + - + key of the submitted hash, for possibilities refer to the extensions spec. To get an overview how the extensions would be defined on grape level, see the following examples:

• verb extension, add a x key to the desc hash:

desc 'This returns something with extension on verb level',
  x: { some: 'stuff' }

this would generate:

"/path":{
  "get":{
    "…":"…",
    "x-some":"stuff"
  }
}

• path extension, by setting via route settings:

route_setting :x_path, { some: 'stuff' }

this would generate:

"/path":{
  "x-some":"stuff",
  "get":{
    "…":"…",
  }
}

• definition extension, again by setting via route settings, here the status code must be provided, for which definition the extensions should be:

route_setting :x_def, { for: 422, other: 'stuff' }

this would generate:

"/definitions":{
  "ApiError":{
    "x-other":"stuff",
    "…":"…",
  }
}

or, for more definitions:

route_setting :x_def, [{ for: 422, other: 'stuff' }, { for: 200, some: 'stuff' }]

<a="example" />

Go into example directory and run it: $ bundle exec rackup go to: http://localhost:9292/swagger_doc to get it

For request examples load the postman file

Use namespace for grouping APIs

class NamespaceApi < Grape::API
  namespace :hudson do
    desc 'Document root'
    get '/' do
    end
  end

  namespace :hudson do
    desc 'This gets something.',
      notes: '_test_'

    get '/simple' do
      { bla: 'something' }
    end
  end

  namespace :colorado do
    desc 'This gets something for URL using - separator.',
      notes: '_test_'

    get '/simple-test' do
      { bla: 'something' }
    end
  end
end
  …

See CONTRIBUTING.

Copyright (c) 2012-2014 Tim Vandecasteele and contributors. See LICENSE.txt for details.