    # File lib/action_controller/request.rb, line 51
        def content_type
          @content_type ||=
            begin
              content_type = @env['CONTENT_TYPE'].to_s.downcase

              if x_post_format = @env['HTTP_X_POST_DATA_FORMAT']
                case x_post_format.to_s.downcase
                when 'yaml'
                  content_type = 'application/x-yaml'
                when 'xml'
                  content_type = 'application/xml'
                end
              end

              Mime::Type.lookup(content_type)
            end
        end