      def original_filename
        filename = filename_from_header || filename_from_uri
        mime_type = MiniMime.lookup_by_content_type(file.content_type)
        unless File.extname(filename).present? || mime_type.blank?
          filename = "#{filename}.#{mime_type.extension}"
        end
        filename
      end
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.