Refactor documentation and code for Apps Script relay mode; remove WebSocket support.

PULL_REQUEST_DRAFT.md

@@ -35,7 +35,7 @@ This PR does not claim full compatibility for all websites. It focuses on making
 
 Local verification:
 
-- `python3 -m py_compile main.py proxy_server.py domain_fronter.py mitm.py h2_transport.py ws.py cert_installer.py`
+- `python3 -m py_compile main.py proxy_server.py domain_fronter.py mitm.py h2_transport.py cert_installer.py`
 
 Observed behavior during manual testing:
 

README.md

@@ -176,14 +176,7 @@ Firefox uses its own certificate store, so even after OS-level install you need
 
 ## Modes Overview
 
-| Mode | What You Need | Description |
+This project focuses entirely on the **Apps Script** relay — a free Google account is all you need, no server, no VPS, no Cloudflare setup. Everything is configured out of the box for this mode.
-|------|--------------|-------------|
-| `apps_script` | Free Google account | **Easiest.** Uses Google Apps Script as relay. No server needed. |
-| `google_fronting` | Google Cloud Run service | Uses your own Cloud Run service behind Google's CDN. |
-| `domain_fronting` | Cloudflare Worker | Uses a Cloudflare Worker as relay. |
-| `custom_domain` | Custom domain on Cloudflare | Connects directly to your domain on Cloudflare. |
-
-Most users should use **`apps_script`** mode — it's free and requires no server.
 
 ---
 
@@ -193,7 +186,6 @@ Most users should use **`apps_script`** mode — it's free and requires no serve
 
 | Setting | What It Does |
 |---------|-------------|
-| `mode` | Which relay type to use (see table above) |
 | `auth_key` | Password shared between your computer and the relay |
 | `script_id` | Your Google Apps Script Deployment ID |
 | `listen_host` | Where to listen (`127.0.0.1` = only this computer) |
@@ -207,8 +199,6 @@ Most users should use **`apps_script`** mode — it's free and requires no serve
 | `google_ip` | `216.239.38.120` | Google IP address to connect through |
 | `front_domain` | `www.google.com` | Domain shown to the firewall/filter |
 | `verify_ssl` | `true` | Verify TLS certificates |
-| `worker_host` | — | Hostname for Cloudflare/Cloud Run modes |
-| `custom_domain` | — | Your custom domain on Cloudflare |
 | `script_ids` | — | Multiple Script IDs for load balancing (array) |
 
 ### Load Balancing
@@ -269,11 +259,10 @@ python3 main.py --no-cert-check          # Skip automatic CA install check on st
 |------|-------------|
 | `main.py` | Starts the proxy |
 | `proxy_server.py` | Handles browser connections |
-| `domain_fronter.py` | Disguises traffic through CDN/Google |
+| `domain_fronter.py` | Apps Script relay client (fronted through Google) |
 | `h2_transport.py` | Faster connections using HTTP/2 (optional) |
 | `mitm.py` | Handles HTTPS certificate generation |
 | `cert_installer.py` | Cross-platform CA certificate installer (Windows/macOS/Linux + Firefox) |
-| `ws.py` | WebSocket support |
 | `Code.gs` | The relay script you deploy to Google Apps Script |
 | `config.example.json` | Example config — copy to `config.json` |
 

README_FA.md

@@ -166,14 +166,7 @@ Firefox معمولا certificate store جداگانه دارد:
 
 ## حالت‌های موجود
 
-| حالت | نیازمندی | توضیح |
+این پروژه کاملاً روی حالت **Apps Script** تمرکز دارد. فقط به یک اکانت رایگان Google نیاز دارید — بدون VPS، بدون سرور، بدون Cloudflare. همه‌چیز برای همین حالت تنظیم شده است.
-|------|----------|-------|
-| `apps_script` | اکانت رایگان Google | ساده‌ترین حالت، بدون نیاز به سرور |
-| `google_fronting` | Google Cloud Run | استفاده از سرویس Cloud Run خودتان |
-| `domain_fronting` | Cloudflare Worker | استفاده از Worker روی Cloudflare |
-| `custom_domain` | دامنه شخصی روی Cloudflare | اتصال مستقیم به دامنه خودتان |
-
-برای اکثر کاربران، `apps_script` بهترین انتخاب است.
 
 ---
 
@@ -181,7 +174,6 @@ Firefox معمولا certificate store جداگانه دارد:
 
 | تنظیم | توضیح |
 |------|-------|
-| `mode` | نوع رله |
 | `auth_key` | رمز مشترک بین برنامه و رله |
 | `script_id` | Deployment ID مربوط به Apps Script |
 | `listen_host` | آدرس محلی برای اجرا |
@@ -195,8 +187,6 @@ Firefox معمولا certificate store جداگانه دارد:
 | `google_ip` | `216.239.38.120` | IP مورد استفاده برای مسیر Google |
 | `front_domain` | `www.google.com` | دامنه‌ای که فیلتر می‌بیند |
 | `verify_ssl` | `true` | بررسی اعتبار TLS |
-| `worker_host` | - | برای حالت‌های Cloudflare/Cloud Run |
-| `custom_domain` | - | دامنه شخصی شما |
 | `script_ids` | - | چند Deployment ID برای load balancing |
 
 ### استفاده از چند Script ID
@@ -255,11 +245,10 @@ python3 main.py --no-cert-check       # رد شدن از بررسی خودکار
 |------|--------|
 | `main.py` | اجرای برنامه |
 | `proxy_server.py` | مدیریت اتصال مرورگر |
-| `domain_fronter.py` | انجام domain fronting |
+| `domain_fronter.py` | کلاینت رله Apps Script (با عبور از Google) |
 | `h2_transport.py` | ارتباط سریع‌تر با HTTP/2 |
 | `mitm.py` | ساخت و مدیریت certificate |
 | `cert_installer.py` | نصب خودکار گواهی CA در ویندوز، مک، لینوکس و Firefox |
-| `ws.py` | پشتیبانی WebSocket |
 | `Code.gs` | رله Apps Script |
 | `config.example.json` | فایل نمونه تنظیمات |
 

domain_fronter.py

@@ -1,19 +1,10 @@
 """
-CDN Relay engine.
+Apps Script relay engine.
 
-Modes:
+Domain fronting via Google Apps Script: POST JSON to script.google.com
-  1. custom_domain   — SNI and Host both point to your custom domain on CF.
+(fronted through www.google.com). Apps Script fetches the target URL and
-  2. domain_fronting  — SNI = front_domain (allowed), Host = worker_host.
+returns the response.
-  3. google_fronting  — Connect to Google IP, SNI=google, Host=Cloud Run.
-  4. apps_script     — Domain fronting via Google Apps Script relay.
-     POST JSON to script.google.com (fronted through www.google.com).
-     Apps Script fetches the target URL and returns the response.
 
-Modes 1-3:
-  tunnel()  — WebSocket-based TCP tunnel (HTTPS / any TCP)
-  forward() — HTTP request forwarding    (plain HTTP)
-
-Mode 4 (apps_script):
   relay()   — JSON-based HTTP relay through Apps Script
 """
 
@@ -23,14 +14,11 @@ import hashlib
 import gzip
 import json
 import logging
-import os
 import re
 import ssl
 import time
 from urllib.parse import urlparse
 
-from ws import ws_encode, ws_decode
-
 log = logging.getLogger("Fronter")
 
 
@@ -42,18 +30,6 @@ class DomainFronter:
     )
 
     def __init__(self, config: dict):
-        mode = config.get("mode", "domain_fronting")
-
-        if mode == "custom_domain":
-            domain = config["custom_domain"]
-            self.connect_host = domain
-            self.sni_host = domain
-            self.http_host = domain
-        elif mode == "google_fronting":
-            self.connect_host = config.get("google_ip", "216.239.38.120")
-            self.sni_host = config.get("front_domain", "www.google.com")
-            self.http_host = config["worker_host"]
-        elif mode == "apps_script":
         self.connect_host = config.get("google_ip", "216.239.38.120")
         self.sni_host = config.get("front_domain", "www.google.com")
         self.http_host = "script.google.com"
@@ -63,13 +39,7 @@ class DomainFronter:
         self._script_idx = 0
         self.script_id = self._script_ids[0]  # backward compat / logging
         self._dev_available = False  # True if /dev endpoint works (no redirect, ~400ms faster)
-        else:
-            self.connect_host = config["front_domain"]
-            self.sni_host = config["front_domain"]
-            self.http_host = config["worker_host"]
 
-        self.mode = mode
-        self.worker_path = config.get("worker_path", "")
         self.auth_key = config.get("auth_key", "")
         self.verify_ssl = config.get("verify_ssl", True)
 
@@ -98,7 +68,6 @@ class DomainFronter:
 
         # HTTP/2 multiplexing — one connection handles all requests
         self._h2 = None
-        if mode == "apps_script":
         try:
             from h2_transport import H2Transport, H2_AVAILABLE
             if H2_AVAILABLE:
@@ -392,140 +361,6 @@ class DomainFronter:
     def _auth_header(self) -> str:
         return f"X-Auth-Key: {self.auth_key}\r\n" if self.auth_key else ""
 
-    # ── WebSocket tunnel (CONNECT / HTTPS) ────────────────────────
-
-    async def tunnel(self, target_host: str, target_port: int,
-                     client_r: asyncio.StreamReader,
-                     client_w: asyncio.StreamWriter):
-        """Tunnel raw TCP bytes through a domain-fronted WebSocket."""
-        try:
-            remote_r, remote_w = await self._open()
-        except Exception as e:
-            log.error("TLS connect to %s failed: %s", self.connect_host, e)
-            return
-
-        try:
-            # ---- WebSocket upgrade ----
-            ws_key = base64.b64encode(os.urandom(16)).decode()
-            path = f"{self.worker_path}/tunnel?host={target_host}&port={target_port}"
-            handshake = (
-                f"GET {path} HTTP/1.1\r\n"
-                f"Host: {self.http_host}\r\n"
-                f"Upgrade: websocket\r\n"
-                f"Connection: Upgrade\r\n"
-                f"Sec-WebSocket-Key: {ws_key}\r\n"
-                f"Sec-WebSocket-Version: 13\r\n"
-                f"{self._auth_header()}"
-                f"\r\n"
-            )
-            remote_w.write(handshake.encode())
-            await remote_w.drain()
-
-            # Read the 101 Switching Protocols response
-            resp = b""
-            while b"\r\n\r\n" not in resp:
-                chunk = await asyncio.wait_for(remote_r.read(4096), timeout=15)
-                if not chunk:
-                    raise ConnectionError("No WebSocket handshake response")
-                resp += chunk
-
-            status_line = resp.split(b"\r\n")[0]
-            if b"101" not in status_line:
-                raise ConnectionError(
-                    f"WebSocket upgrade rejected: {status_line.decode(errors='replace')}"
-                )
-
-            log.info("Tunnel ready → %s:%d", target_host, target_port)
-
-            # ---- bidirectional relay ----
-            await asyncio.gather(
-                self._client_to_ws(client_r, remote_w),
-                self._ws_to_client(remote_r, client_w),
-            )
-
-        except Exception as e:
-            log.error("Tunnel error (%s:%d): %s", target_host, target_port, e)
-        finally:
-            try:
-                remote_w.close()
-            except Exception:
-                pass
-
-    async def _client_to_ws(self, src: asyncio.StreamReader,
-                            dst: asyncio.StreamWriter):
-        """Read plaintext from the browser, wrap in WS frames, send to CDN."""
-        try:
-            while True:
-                data = await src.read(16384)
-                if not data:
-                    # Send a WS close frame
-                    dst.write(ws_encode(b"", opcode=0x08))
-                    await dst.drain()
-                    break
-                dst.write(ws_encode(data))
-                await dst.drain()
-        except (ConnectionError, asyncio.CancelledError):
-            pass
-
-    async def _ws_to_client(self, src: asyncio.StreamReader,
-                            dst: asyncio.StreamWriter):
-        """Read WS frames from CDN, unwrap, write plaintext to browser."""
-        buf = b""
-        try:
-            while True:
-                chunk = await src.read(16384)
-                if not chunk:
-                    break
-                buf += chunk
-                while buf:
-                    result = ws_decode(buf)
-                    if result is None:
-                        break  # need more data
-                    opcode, payload, consumed = result
-                    buf = buf[consumed:]
-                    if opcode == 0x08:  # close
-                        return
-                    if payload:
-                        dst.write(payload)
-                        await dst.drain()
-        except (ConnectionError, asyncio.CancelledError):
-            pass
-
-    # ── HTTP forwarding ───────────────────────────────────────────
-
-    async def forward(self, raw_request: bytes) -> bytes:
-        """Forward a plain HTTP request through the domain-fronted channel.
-
-        Uses keep-alive connections from the pool for efficiency.
-        """
-        try:
-            reader, writer, created = await self._acquire()
-
-            # Wrap the original HTTP request inside a POST to the worker.
-            request = (
-                f"POST {self.worker_path}/forward HTTP/1.1\r\n"
-                f"Host: {self.http_host}\r\n"
-                f"Content-Type: application/octet-stream\r\n"
-                f"Content-Length: {len(raw_request)}\r\n"
-                f"Connection: keep-alive\r\n"
-                f"{self._auth_header()}"
-                f"\r\n"
-            )
-            writer.write(request.encode() + raw_request)
-            await writer.drain()
-
-            status, resp_headers, resp_body = await self._read_http_response(reader)
-
-            await self._release(reader, writer, created)
-
-            # The worker wraps the target's response in its own HTTP
-            # envelope.  The body IS the raw HTTP response from the target.
-            return resp_body
-
-        except Exception as e:
-            log.error("Forward failed: %s", e)
-            return b"HTTP/1.1 502 Bad Gateway\r\n\r\nDomain fronting request failed\r\n"
-
     # ── Apps Script relay (apps_script mode) ──────────────────────
 
     async def relay(self, method: str, url: str,

main.py

@@ -1,10 +1,10 @@
 #!/usr/bin/env python3
 """
-DomainFront Tunnel — Bypass DPI censorship via Domain Fronting.
+DomainFront Tunnel — Bypass DPI censorship via Google Apps Script.
 
-Run a local HTTP proxy that tunnels all traffic through a CDN using
+Run a local HTTP proxy that tunnels all traffic through a Google Apps
-domain fronting: the TLS SNI shows an allowed domain while the encrypted
+Script relay fronted by www.google.com (TLS SNI shows www.google.com
-HTTP Host header routes to your Cloudflare Worker relay.
+while the encrypted Host header points at script.google.com).
 """
 
 import argparse
@@ -33,7 +33,7 @@ def setup_logging(level_name: str):
 def parse_args():
     parser = argparse.ArgumentParser(
         prog="domainfront-tunnel",
-        description="Local HTTP proxy that tunnels traffic through domain fronting.",
+        description="Local HTTP proxy that relays traffic through Google Apps Script.",
     )
     parser.add_argument(
         "-c", "--config",
@@ -136,24 +136,12 @@ def main():
             print(f"Missing required config key: {key}")
             sys.exit(1)
 
-    mode = config.get("mode", "domain_fronting")
+    # Always Apps Script mode — force-set for backward-compat configs.
-    if mode == "custom_domain" and "custom_domain" not in config:
+    config["mode"] = "apps_script"
-        print("Mode 'custom_domain' requires 'custom_domain' in config")
-        sys.exit(1)
-    if mode == "domain_fronting":
-        for key in ("front_domain", "worker_host"):
-            if key not in config:
-                print(f"Mode 'domain_fronting' requires '{key}' in config")
-                sys.exit(1)
-    if mode == "google_fronting":
-        if "worker_host" not in config:
-            print("Mode 'google_fronting' requires 'worker_host' in config (your Cloud Run URL)")
-            sys.exit(1)
-    if mode == "apps_script":
     sid = config.get("script_ids") or config.get("script_id")
     if not sid or (isinstance(sid, str) and sid == "YOUR_APPS_SCRIPT_DEPLOYMENT_ID"):
-            print("Mode 'apps_script' requires 'script_id' in config.")
+        print("Missing 'script_id' in config.")
-            print("Deploy the Apps Script from appsscript/Code.gs and paste the Deployment ID.")
+        print("Deploy the Apps Script from Code.gs and paste the Deployment ID.")
         sys.exit(1)
 
     # ── Certificate installation ──────────────────────────────────────────
@@ -167,16 +155,8 @@ def main():
     setup_logging(config.get("log_level", "INFO"))
     log = logging.getLogger("Main")
 
-    mode = config.get("mode", "domain_fronting")
+    log.info("DomainFront Tunnel starting (Apps Script relay)")
-    log.info("DomainFront Tunnel starting (mode: %s)", mode)
 
-    if mode == "custom_domain":
-        log.info("Custom domain    : %s", config["custom_domain"])
-    elif mode == "google_fronting":
-        log.info("Google fronting   : SNI=%s → Host=%s",
-                 config.get("front_domain", "www.google.com"), config["worker_host"])
-        log.info("Google IP         : %s", config.get("google_ip", "216.239.38.120"))
-    elif mode == "apps_script":
     log.info("Apps Script relay : SNI=%s → script.google.com",
              config.get("front_domain", "www.google.com"))
     script_ids = config.get("script_ids") or config.get("script_id")
@@ -207,9 +187,6 @@ def main():
                 )
         else:
             log.info("MITM CA is already trusted.")
-    else:
-        log.info("Front domain (SNI) : %s", config.get("front_domain", "?"))
-        log.info("Worker host (Host) : %s", config.get("worker_host", "?"))
 
     log.info("HTTP proxy         : %s:%d",
              config.get("listen_host", "127.0.0.1"),

proxy_server.py

@@ -2,11 +2,8 @@
 Local HTTP proxy server.
 
 Intercepts the user's browser traffic and forwards everything through
-a domain-fronted connection to a CDN worker or Apps Script relay.
+the Apps Script relay (MITM-decrypts HTTPS locally, forwards requests
-
+as JSON to script.google.com fronted through www.google.com).
-Supports:
-  - CONNECT method  → WebSocket tunnel (modes 1-3) or MITM relay (apps_script)
-  - GET / POST etc. → HTTP forwarding  (modes 1-3) or JSON relay (apps_script)
 """
 
 import asyncio
@@ -150,17 +147,11 @@ class ProxyServer:
         self.socks_enabled = config.get("socks5_enabled", True)
         self.socks_host = config.get("socks5_host", self.host)
         self.socks_port = config.get("socks5_port", 1080)
-        self.mode = config.get("mode", "domain_fronting")
         self.fronter = DomainFronter(config)
         self.mitm = None
         self._cache = ResponseCache(max_mb=50)
         self._direct_fail_until: dict[str, float] = {}
 
-        # Persistent HTTP tunnel cache for google_fronting mode
-        # Key: "host:port" → (tunnel_reader, tunnel_writer, lock)
-        self._http_tunnels: dict = {}
-        self._tunnel_lock = asyncio.Lock()
-
         # hosts override — DNS fake-map: domain/suffix → IP
         # Checked before any real DNS lookup; supports exact and suffix matching.
         self._hosts: dict[str, str] = config.get("hosts", {})
@@ -181,12 +172,11 @@ class ProxyServer:
             )
         }
 
-        if self.mode == "apps_script":
         try:
             from mitm import MITMCertManager
             self.mitm = MITMCertManager()
         except ImportError:
-                log.error("apps_script mode requires 'cryptography' package.")
+            log.error("Apps Script relay requires the 'cryptography' package.")
             log.error("Run: pip install cryptography")
             raise SystemExit(1)
 
@@ -406,9 +396,8 @@ class ProxyServer:
     async def _handle_target_tunnel(self, host: str, port: int,
                                     reader: asyncio.StreamReader,
                                     writer: asyncio.StreamWriter):
-        """Route a target connection through the active relay mode."""
+        """Route a target connection through the Apps Script relay."""
 
-        if self.mode == "apps_script":
         override_ip = self._sni_rewrite_ip(host)
         if override_ip:
             # SNI-blocked domain: MITM-decrypt from browser, then
@@ -442,8 +431,6 @@ class ProxyServer:
             await self._do_mitm_connect(host, port, reader, writer)
         else:
             await self._do_plain_http_tunnel(host, port, reader, writer)
-        else:
-            await self.fronter.tunnel(host, port, reader, writer)
 
     # ── Hosts override (fake DNS) ─────────────────────────────────
 
@@ -1028,7 +1015,6 @@ class ProxyServer:
         first_line = header_block.split(b"\r\n")[0].decode(errors="replace")
         log.info("HTTP → %s", first_line)
 
-        if self.mode == "apps_script":
         # Parse request and relay through Apps Script
         parts = first_line.strip().split(" ", 2)
         method = parts[0] if parts else "GET"
@@ -1077,68 +1063,6 @@ class ProxyServer:
         if origin and response:
             response = self._inject_cors_headers(response, origin)
         self._log_response_summary(url, response)
-        elif self.mode in ("google_fronting", "custom_domain", "domain_fronting"):
-            # Use WebSocket tunnel for ALL traffic (much faster than forward())
-            response = await self._tunnel_http(header_block, body)
-        else:
-            response = await self.fronter.forward(header_block + body)
 
         writer.write(response)
         await writer.drain()
-
-    async def _tunnel_http(self, header_block: bytes, body: bytes) -> bytes:
-        """Forward plain HTTP via a persistent WebSocket tunnel.
-
-        Instead of opening a new TLS+HTTP connection for each request
-        (the old forward() path), this keeps a WebSocket tunnel open
-        to the target host and pipes raw HTTP through it.
-        Much faster for rapid-fire requests (e.g., Telegram API).
-        """
-        # Parse target host:port from the raw HTTP request
-        host = ""
-        port = 80
-        for line in header_block.split(b"\r\n")[1:]:
-            if not line:
-                break
-            if line.lower().startswith(b"host:"):
-                host_val = line.split(b":", 1)[1].strip().decode(errors="replace")
-                if ":" in host_val:
-                    h, p = host_val.rsplit(":", 1)
-                    try:
-                        host, port = h, int(p)
-                    except ValueError:
-                        host = host_val
-                else:
-                    host = host_val
-                break
-
-        if not host:
-            return b"HTTP/1.1 400 Bad Request\r\n\r\nNo Host header\r\n"
-
-        # Rewrite the request line: browser sends absolute URL
-        # (e.g., "GET http://host/path HTTP/1.1") but the target
-        # server expects a relative path ("GET /path HTTP/1.1")
-        first_line = header_block.split(b"\r\n")[0]
-        first_str = first_line.decode(errors="replace")
-        parts = first_str.split(" ", 2)
-        if len(parts) >= 2 and parts[1].startswith("http://"):
-            from urllib.parse import urlparse
-            parsed = urlparse(parts[1])
-            rel_path = parsed.path or "/"
-            if parsed.query:
-                rel_path += "?" + parsed.query
-            new_first = f"{parts[0]} {rel_path}"
-            if len(parts) == 3:
-                new_first += f" {parts[2]}"
-            header_block = new_first.encode() + b"\r\n" + b"\r\n".join(header_block.split(b"\r\n")[1:])
-
-        raw_request = header_block + body
-
-        # Send through tunnel
-        try:
-            return await asyncio.wait_for(
-                self.fronter.forward(raw_request), timeout=30
-            )
-        except Exception as e:
-            log.error("Tunnel HTTP failed (%s:%d): %s", host, port, e)
-            return b"HTTP/1.1 502 Bad Gateway\r\n\r\nTunnel forward failed\r\n"

ws.py

@@ -1,76 +0,0 @@
-"""
-Minimal WebSocket frame encoder / decoder (RFC 6455).
-
-Only handles binary (opcode 0x02) and close (opcode 0x08) frames.
-Client-to-server frames are always masked as required by the spec.
-"""
-
-import os
-import struct
-
-
-def ws_encode(data: bytes, opcode: int = 0x02) -> bytes:
-    """Encode *data* into a masked binary WebSocket frame."""
-    head = bytearray([0x80 | opcode])  # FIN + opcode
-
-    length = len(data)
-    if length < 126:
-        head.append(0x80 | length)
-    elif length < 0x10000:
-        head.append(0x80 | 126)
-        head += struct.pack("!H", length)
-    else:
-        head.append(0x80 | 127)
-        head += struct.pack("!Q", length)
-
-    mask = os.urandom(4)
-    head += mask
-
-    masked = bytearray(data)
-    for i in range(len(masked)):
-        masked[i] ^= mask[i & 3]
-
-    return bytes(head) + bytes(masked)
-
-
-def ws_decode(buf: bytes):
-    """Try to decode one frame from *buf*.
-
-    Returns ``(opcode, payload, consumed_bytes)`` or ``None`` if the
-    buffer does not yet contain a complete frame.
-    """
-    if len(buf) < 2:
-        return None
-
-    opcode = buf[0] & 0x0F
-    is_masked = buf[1] & 0x80
-    length = buf[1] & 0x7F
-    pos = 2
-
-    if length == 126:
-        if len(buf) < 4:
-            return None
-        length = struct.unpack("!H", buf[2:4])[0]
-        pos = 4
-    elif length == 127:
-        if len(buf) < 10:
-            return None
-        length = struct.unpack("!Q", buf[2:10])[0]
-        pos = 10
-
-    mask = None
-    if is_masked:
-        if len(buf) < pos + 4:
-            return None
-        mask = buf[pos : pos + 4]
-        pos += 4
-
-    if len(buf) < pos + length:
-        return None
-
-    payload = bytearray(buf[pos : pos + length])
-    if mask:
-        for i in range(len(payload)):
-            payload[i] ^= mask[i & 3]
-
-    return opcode, bytes(payload), pos + length