# File lib/rabl/engine.rb, line 211
    def request_format
      format = self.request_params.has_key?(:format) ? context_scope.params[:format] : nil
      if request = context_scope.respond_to?(:request) && context_scope.request
        format ||= request.format.to_sym.to_s if request.respond_to?(:format)
      end
      format && self.respond_to?("to_#{format}") ? format : "json"
    end