"""
Minimal, mac-safe CDP transport patch.
Goal: reduce visible control-channel fingerprints (e.g., Playwright
headers) without breaking protocol. This is intentionally conservative:
- strips obvious "User-Agent" header from the websocket handshake
- leaves Sec-WebSocket-Protocol intact to avoid breaking Chromium
"""
from __future__ import annotations
import logging
from typing import Any, Dict
logger = logging.getLogger(__name__)
def _patch_websocket_transport() -> None:
try:
from playwright._impl._transport import WebSocketTransport
except Exception as exc: # pragma: no cover
logger.debug("CDP patch skipped: cannot import WebSocketTransport: %s", exc)
return
original_init = WebSocketTransport.__init__
def patched_init(self, *, ws_endpoint: str, headers: Dict[str, str] | None = None, **kwargs: Any):
headers = dict(headers or {})
headers.pop("User-Agent", None) # drop Playwright UA marker in handshake
return original_init(self, ws_endpoint=ws_endpoint, headers=headers, **kwargs)
WebSocketTransport.__init__ = patched_init # type: ignore[assignment]
def apply() -> None:
"""Apply CDP transport tweaks. Safe to call multiple times."""
try:
_patch_websocket_transport()
except Exception as exc: # pragma: no cover
logger.warning("Failed to apply CDP transport patch: %s", exc)
