forward_local fail, command:%s, path:%s, headers: %s, payloa

Error message

forward_local fail, command:%s, path:%s, headers: %s, payload: %s

What it means

forward_local attempted the local direct HTTP request via simple_http_client.request() and got a falsy response (None/empty), meaning the local connection to the target failed entirely. The command, path, headers and payload are logged for diagnosis before returning.

Source

Thrown at code/default/gae_proxy/local/proxy_handler.py:109

    def forward_local(self):
        """
        If browser send localhost:xxx request to GAE_proxy,
        we forward it to localhost.
        """
        request_headers = dict((k.title(), v) for k, v in list(self.headers.items()))
        payload = b''
        if b'Content-Length' in request_headers:
            try:
                payload_len = int(request_headers.get(b'Content-Length', 0))
                payload = self.rfile.read(payload_len)
            except Exception as e:
                xlog.warn('forward_local read payload failed:%s', e)
                return

        response = simple_http_client.request(self.command, self.path, request_headers, payload)
        if not response:
            xlog.warn("forward_local fail, command:%s, path:%s, headers: %s, payload: %s",
                self.command, self.path, request_headers, payload)
            return

        out_list = []
        out_list.append(b"HTTP/1.1 %d\r\n" % response.status)
        for key in response.headers:
            key = key.title()
            out_list.append(b"%s: %s\r\n" % (key, response.headers[key]))
        out_list.append(b"\r\n")
        out_list.append(response.text)

        self.wfile.write(b"".join(out_list))

    def send_method_allows(self, headers, payload):
        xlog.debug("send method allow list for:%s %s", self.command, self.path)
        # Refer: https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS#Preflighted_requests

        response = \

View on GitHub (pinned to cfa5bc17b6)

Solutions

Check basic local connectivity to the host (curl --resolve / ping the resolved IP)
Verify DNS resolution is correct; switch to a trusted DNS resolver to rule out pollution
Let the proxy fall back to the GAE/AGENT path for blocked sites instead of DIRECT
If it affects all sites, fix the local network/firewall before debugging the proxy

Defensive patterns

Strategy: fallback

Validate before calling

import socket
try:
    socket.create_connection((host, 80), timeout=3).close()
    direct_ok = True
except OSError:
    direct_ok = False

Try / catch

response = simple_http_client.request(...)
if not response:
    xlog.warn('forward_local fail ...')
    self.go_AGENT()  # retry via GAE instead of failing the client

Prevention

Add a connectivity precheck before direct forwarding
Automatically fall back to the GAE path when DIRECT returns nothing
Retry once with fresh DNS to dodge polluted resolution

When it happens

Trigger: simple_http_client.request() returns None because the TCP connection to the origin failed, the connection was reset, or the response could not be parsed — e.g. target site unreachable, local network down, DNS failure, or firewall reset.

Common situations: Target site blocked or unreachable from the local network; local internet outage; DNS pollution resolving the host to a bogus IP; the site resetting non-proxy connections. Compare with the GAE path: if DIRECT fails but GAE works, it's network blocking.

Related errors

AI-assisted analysis of XX-net/XX-Net@cfa5bc17b6 (2026-08-27). Data as JSON: /api/errors/28db80be11f4b3c4. Report an issue: GitHub.