ft/CodexOutput/upserver/network_fault_proxy.py

"""Loopback-only, fixed-upstream transport fixture. Never logs headers or payloads."""
import http.client
import json
import select
import socket
import socketserver
import threading
import time
from pathlib import Path
from urllib.parse import urlsplit, parse_qs

ROOT = Path(__file__).parent
HOST, PORT = 's101.local', 18080
lock = threading.Lock()
state = dict(mode='pass', blocked_until=0, upgrades=0, active=0, negotiate=0,
             login_forwarded=0, faults=0, errors=0)
channels = set()


def snapshot():
    with lock:
        return {k: v for k, v in state.items() if k != 'blocked_until'}


class Handler(socketserver.BaseRequestHandler):
    def reply(self, code, body=b'', extra=()):
        headers = [('Content-Length', str(len(body))), ('Connection', 'close'), *extra]
        data = f'HTTP/1.1 {code} Result\r\n' + ''.join(f'{k}: {v}\r\n' for k, v in headers)
        self.request.sendall(data.encode('latin1') + b'\r\n' + body)

    def handle(self):
        upstream = None
        registered = False
        try:
            self.request.settimeout(25)
            incoming = b''
            while b'\r\n\r\n' not in incoming:
                chunk = self.request.recv(4096)
                if not chunk:
                    return
                incoming += chunk
                if len(incoming) > 65536:
                    return
            head, body = incoming.split(b'\r\n\r\n', 1)
            lines = head.decode('latin1').split('\r\n')
            method, target, _ = lines[0].split(' ')
            headers = dict(line.split(':', 1) for line in lines[1:])
            lower = {k.lower(): v.strip() for k, v in headers.items()}
            parsed = urlsplit(target)
            path = parsed.path
            if path == '/__status':
                self.reply(200, json.dumps(snapshot()).encode())
                return
            if path == '/__control':
                mode = parse_qs(parsed.query).get('mode', [''])[0]
                if mode not in ('pass', '401', 'timeout', 'reset', 'drop', 'stop'):
                    self.reply(400)
                    return
                with lock:
                    if mode == 'drop':
                        state['blocked_until'] = time.monotonic() + 3
                        victims = list(channels)
                    else:
                        state['mode'] = mode
                        victims = []
                for peer in victims:
                    try:
                        peer.shutdown(socket.SHUT_RDWR)
                    except OSError:
                        pass
                self.reply(200, b'OK')
                if mode == 'stop':
                    threading.Thread(target=self.server.shutdown, daemon=True).start()
                return
            if path == '/gamehub/negotiate':
                with lock:
                    state['negotiate'] += 1
                self.reply(403)
                return
            if path == '/gamehub' and lower.get('upgrade', '').lower() == 'websocket':
                with lock:
                    blocked = time.monotonic() < state['blocked_until']
                if blocked:
                    self.reply(503)
                    return
                upstream = socket.create_connection((HOST, PORT), timeout=8)
                rebuilt = [lines[0]] + [f'{k}: {v.strip()}' for k, v in headers.items() if k.lower() != 'host']
                rebuilt.append(f'Host: {HOST}:{PORT}')
                upstream.sendall(('\r\n'.join(rebuilt) + '\r\n\r\n').encode('latin1') + body)
                response = b''
                while b'\r\n\r\n' not in response:
                    response += upstream.recv(4096)
                    if len(response) > 65536:
                        raise ValueError('oversized upgrade')
                self.request.sendall(response)
                if not response.startswith(b'HTTP/1.1 101 '):
                    return
                with lock:
                    state['upgrades'] += 1
                    state['active'] += 1
                    channels.add(self.request)
                registered = True
                peers = (self.request, upstream)
                while True:
                    ready, _, _ = select.select(peers, [], [], 1)
                    for src in ready:
                        chunk = src.recv(65536)
                        if not chunk:
                            return
                        (upstream if src is self.request else self.request).sendall(chunk)
                return
            if method != 'POST' or path not in ('/account/Login', '/playerdata/Get'):
                self.reply(403)
                return
            size = int(lower.get('content-length', '0'))
            if size > 2048 or 'transfer-encoding' in lower:
                self.reply(400)
                return
            while len(body) < size:
                chunk = self.request.recv(size - len(body))
                if not chunk:
                    return
                body += chunk
            payload = json.loads(body[:size])
            if (path == '/account/Login' and payload not in ({'playerId': '101'}, {'playerId': '102'})) or (path == '/playerdata/Get' and payload != {}):
                self.reply(403)
                return
            with lock:
                mode = state['mode']
                if path == '/account/Login' and mode in ('401', 'timeout', 'reset'):
                    state['mode'] = 'pass'
                    state['faults'] += 1
                else:
                    mode = 'pass'
            if mode == '401':
                self.reply(401)
                return
            if mode == 'timeout':
                time.sleep(18)
                self.reply(504)
                return
            if mode == 'reset':
                self.request.shutdown(socket.SHUT_RDWR)
                return
            conn = http.client.HTTPConnection(HOST, PORT, timeout=10)
            try:
                forward = {'Content-Type': 'application/json'}
                if 'cookie' in lower:
                    forward['Cookie'] = lower['cookie']
                conn.request('POST', path, body=body[:size], headers=forward)
                res = conn.getresponse()
                value = res.read()
                extra = [(k, v) for k, v in res.getheaders() if k.lower() in ('set-cookie', 'content-type')]
                self.reply(res.status, value, extra)
                if path == '/account/Login':
                    with lock:
                        state['login_forwarded'] += 1
            finally:
                conn.close()
        except (OSError, ValueError):
            with lock:
                state['errors'] += 1
        finally:
            if registered:
                with lock:
                    channels.discard(self.request)
                    state['active'] -= 1
            if upstream:
                upstream.close()


class Server(socketserver.ThreadingTCPServer):
    daemon_threads = True


with Server(('127.0.0.1', 0), Handler) as server:
    (ROOT / 'network-proxy-address.json').write_text(json.dumps({'url': f'http://127.0.0.1:{server.server_address[1]}/'}))
    print('Loopback transport fixture started; fixed upstream s101.local:18080', flush=True)
    try:
        server.serve_forever(poll_interval=0.2)
    finally:
        (ROOT / 'network-proxy-final.json').write_text(json.dumps(snapshot(), indent=2))