# File lib/rabl/engine.rb, line 311
      def request_format
        format = request_params[:format]

        if format.nil? && context_scope.respond_to?(:request)
          request = context_scope.request
          format = request.format.to_sym.to_s if request.respond_to?(:format)
        end

        format = "json" unless format && respond_to?("to_#{format}")

        format
      end