code: def _uri(self, url):
          
          if url and not url.startswith('/'):
              # Then this must be a proxy request.
              return url
          uri = "{0}://{1}{2}{3}".format(
              self._protocol,
              self.real_connection.host,
              self._port_postfix(),
              url,
          )
          return uri
docs: Returns request absolute URI