code: def get_gconf_http_proxy ():
      
      try:
          import gconf
      except ImportError:
          return None
      try:
          client = gconf.client_get_default()
          if client.get_bool("/system/http_proxy/use_http_proxy"):
              host = client.get_string("/system/http_proxy/host")
              port = client.get_int("/system/http_proxy/port")
              if host:
                  if not port:
                      port = 8080
                  return "%s:%d" % (host, port)
      except Exception as msg:
          log.debug(LOG_CHECK, "error getting HTTP proxy from gconf: %s", msg)
          pass
      return None
docs: Return host:port for GConf HTTP proxy if found, else None.