# File lib/action_dispatch/http/mime_negotiation.rb, line 8
      def content_mime_type
        @env["action_dispatch.request.content_type"] ||= begin
          if @env['CONTENT_TYPE'] =~ /^([^,\;]*)/
            Mime::Type.lookup($1.strip.downcase)
          else
            nil
          end
        end
      end