grape-swagger/lib/grape-swagger.rb

module Grape
  class API
    class << self
      attr_reader :combined_routes

      alias original_mount mount

      def mount(mounts)
        original_mount mounts
        @combined_routes ||= {}
        @combined_routes[mounts.name.split('::').last.downcase] = mounts::routes
      end

      def add_swagger_documentation(options={})
        documentation_class = create_documentation_class

        documentation_class.setup(self)
        mount(documentation_class)
      end

      private

      def create_documentation_class(options={})
        Class.new(Grape::API) do
          class << self
            def name
              'swagger_doc'
            end
          end

          def self.setup(target_class)
            @@target_class = target_class
          end


          helpers do
            def parse_params(params)
              params.map do |param, value|
                dataType = value.is_a?(Hash) ? value[:type]||'String' : 'String'
                description = value.is_a?(Hash) ? value[:desc] : ''
                required = value.is_a?(Hash) ? !!value[:required] : false
                paramType = 'path'
                {
                  paramType: paramType,
                  name: param,
                  description: description,
                  dataType: "String",
                  required: required
                }
              end
            end

            def parse_path(path)
              # adapt format to swagger format
              parsed_path = path.gsub('(.:format)', '.{format}')
              # adapt params to swagger format
              parsed_path.gsub(/:([a-z]+)/, '{\1}')
            end
          end

          desc 'Swagger compatible API description'
          get '/swagger_doc' do
            header['Access-Control-Allow-Origin'] = '*'
            header['Access-Control-Request-Method'] = '*'
            routes = @@target_class::combined_routes

            routes_array = routes.keys.map do |route|
                { :path => "/swagger_doc/#{route}.{format}" }
            end
            {
              apiVersion: "0.2",
              swaggerVersion: "1.1",
              basePath: "http://#{env['HTTP_HOST']}",
              operations:[],
              apis: routes_array
            }
          end

          desc 'Swagger compatible API description for specific API', :params =>
            {
              "name" => { :desc => "Class name of mounted API", :type => "string", :required => true },
            }
          get '/swagger_doc/:name' do
            header['Access-Control-Allow-Origin'] = '*'
            header['Access-Control-Request-Method'] = '*'
            routes = @@target_class::combined_routes[params[:name]]
            routes_array = routes.map do |route|
              {
                :path => parse_path(route.route_path),
                :operations => [{
                  :notes => route.route_notes,
                  :summary => route.route_description || '',
                  :nickname   => Random.rand(1000000),
                  :httpMethod => route.route_method,
                  :parameters => parse_params(route.route_params)
                }]
              }
            end

            {
              apiVersion: "0.2",
              swaggerVersion: "1.1",
              basePath: "http://#{env['HTTP_HOST']}",
              resourcePath: "",
              apis: routes_array
            }
          end
        end
      end
    end
  end
end