Swagger::Blocks

Swagger::Blocks is a DSL for pure Ruby code blocks that can be turned into JSON.

It helps you write API docs in the Swagger style in Ruby and then automatically build JSON that is compatible with Swagger UI.

Features

Supports live updating by design. Change code, refresh your API docs.
Works with all Ruby web frameworks including Rails, Sinatra, etc.
100% support for all features of the Swagger 1.2 and Swagger 2.0 specs.
Flexible—you can use Swagger::Blocks anywhere, split up blocks to fit your style preferences, etc. Since it's pure Ruby and serves definitions dynamically, you can easily use initializers/config objects to change values or even show different APIs based on environment.
1:1 naming with the Swagger spec—block names and nesting should match almost exactly with the swagger spec, with rare exceptions to make things more convenient.

Swagger UI demo

http://petstore.swagger.wordnik.com/#!/pet

Installation

Add this line to your application's Gemfile:

gem 'swagger-blocks'

Or install directly with gem install swagger-blocks.

Swagger 2.0 example (Rails)

This is a simplified example based on the objects in the Petstore Swagger Sample App. For a more complex and complete example, see the swagger_v2_blocks_spec.rb file, or see the v1.2 docs.

Also note that Rails is not required, you can use Swagger::Blocks in plain Ruby objects.

PetsController

class PetsController < ActionController::Base
  include Swagger::Blocks

  swagger_path '/pets/{id}' do
    operation :get do
      key :description, 'Returns a single pet if the user has access'
      key :operationId, 'findPetById'
      key :tags, [
        'pet'
      ]
      parameter do
        key :name, :id
        key :in, :path
        key :description, 'ID of pet to fetch'
        key :required, true
        key :type, :integer
        key :format, :int64
      end
      response 200 do
        key :description, 'pet response'
        schema do
          key :'$ref', :Pet
        end
      end
      response :default do
        key :description, 'unexpected error'
        schema do
          key :'$ref', :ErrorModel
        end
      end
    end
  end
  swagger_path '/pets' do
    operation :get do
      key :description, 'Returns all pets from the system that the user has access to'
      key :operationId, 'findPets'
      key :produces, [
        'application/json',
        'text/html',
      ]
      key :tags, [
        'pet'
      ]
      parameter do
        key :name, :tags
        key :in, :query
        key :description, 'tags to filter by'
        key :required, false
        key :type, :array
        items do
          key :type, :string
        end
        key :collectionFormat, :csv
      end
      parameter do
        key :name, :limit
        key :in, :query
        key :description, 'maximum number of results to return'
        key :required, false
        key :type, :integer
        key :format, :int32
      end
      response 200 do
        key :description, 'pet response'
        schema do
          key :type, :array
          items do
            key :'$ref', :Pet
          end
        end
      end
      response :default do
        key :description, 'unexpected error'
        schema do
          key :'$ref', :ErrorModel
        end
      end
    end
    operation :post do
      key :description, 'Creates a new pet in the store.  Duplicates are allowed'
      key :operationId, 'addPet'
      key :produces, [
        'application/json'
      ]
      key :tags, [
        'pet'
      ]
      parameter do
        key :name, :pet
        key :in, :body
        key :description, 'Pet to add to the store'
        key :required, true
        schema do
          key :'$ref', :PetInput
        end
      end
      response 200 do
        key :description, 'pet response'
        schema do
          key :'$ref', :Pet
        end
      end
      response :default do
        key :description, 'unexpected error'
        schema do
          key :'$ref', :ErrorModel
        end
      end
    end
  end

  # ...
end

Models

Pet model

class Pet < ActiveRecord::Base
  include Swagger::Blocks

  swagger_schema :Pet do
    key :required, [:id, :name]
    property :id do
      key :type, :integer
      key :format, :int64
    end
    property :name do
      key :type, :string
    end
    property :tag do
      key :type, :string
    end
  end

  swagger_schema :PetInput do
    allOf do
      schema do
        key :'$ref', :Pet
      end
      schema do
        key :required, [:name]
        property :id do
          key :type, :integer
          key :format, :int64
        end
      end
    end
  end

  # ...
end

Error model

class ErrorModel  # Notice, this is just a plain ruby object.
  include Swagger::Blocks

  swagger_schema :ErrorModel do
    key :required, [:code, :message]
    property :code do
      key :type, :integer
      key :format, :int32
    end
    property :message do
      key :type, :string
    end
  end
end

Docs controller

To integrate these definitions with Swagger UI, we need a docs controller that can serve the JSON definitions.

resources :apidocs, only: [:index]

class ApidocsController < ActionController::Base
  include Swagger::Blocks

  swagger_root do
    key :swagger, '2.0'
    info do
      key :version, '1.0.0'
      key :title, 'Swagger Petstore'
      key :description, 'A sample API that uses a petstore as an example to ' \
                        'demonstrate features in the swagger-2.0 specification'
      key :termsOfService, 'http://helloreverb.com/terms/'
      contact do
        key :name, 'Wordnik API Team'
      end
      license do
        key :name, 'MIT'
      end
    end
    tags do
      key :name, 'pet'
      key :description, 'Pets operations'
      externalDocs do
        key :description, 'Find more info here'
        key :url, 'https://swagger.io'
      end
    end
    key :host, 'petstore.swagger.wordnik.com'
    key :basePath, '/api'
    key :consumes, ['application/json']
    key :produces, ['application/json']
  end

  # A list of all classes that have swagger_* declarations.
  SWAGGERED_CLASSES = [
    PetsController,
    Pet,
    ErrorModel,
    self,
  ].freeze

  def index
    render json: Swagger::Blocks.build_root_json(SWAGGERED_CLASSES)
  end
end

The special part of this controller is this line:

render json: Swagger::Blocks.build_root_json(SWAGGERED_CLASSES)

That is the only line necessary to build the full root Swagger object JSON and all definitions underneath it. You simply pass in a list of all the "swaggered" classes in your app.

Now, simply point Swagger UI at /apidocs and everything should Just Work™. If you change any of the Swagger block definitions, you can simply refresh Swagger UI to see the changes.

Writing JSON to a file

If you are not serving the JSON directly and need to write it to a file for some reason, you can easily use build_root_json for that as well:

swagger_data = Swagger::Blocks.build_root_json(SWAGGERED_CLASSES)
File.open('swagger.json', 'w') { |file| file.write(swagger_data.to_json) }

Swagger 1.2 example (Rails)

See the v1.2 docs.

Reference

See the swagger_v2_blocks_spec.rb for examples of more complex features and declarations possible.

Contributing

Fork it ( https://github.com/fotinakis/swagger-blocks/fork )
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Add some feature')
Push to the branch (git push origin my-new-feature)
Create a new Pull Request

Release notes

v1.1.1: Bugfix for tags node support.
v1.1: Support for Swagger 2.0 spec.
v1.0.1: Make backwards-compatible with Ruby 1.9.3.
v1.0.0: Initial major release.

Credits

Thanks to @ali-graham for contributing support for Swagger 2.0.

Original idea inspired by @richhollis's swagger-docs gem.

mikechau/swagger-blocks