method_missing

# File actionpack/lib/action_controller/mime_responds.rb, line 143
      def method_missing(symbol, &block)
        mime_constant = symbol.to_s.upcase

        if Mime::SET.include?(Mime.const_get(mime_constant))
          custom(Mime.const_get(mime_constant), &block)
        else
          super
        end
      end