guanlan-src/vendor/pyfastapi/uvicorn/protocols/websockets/auto.py

from __future__ import annotations

import asyncio
from collections.abc import Callable

AutoWebSocketsProtocol: Callable[..., asyncio.Protocol] | None
try:
    import websockets  # noqa
except ImportError:  # pragma: no cover
    try:
        import wsproto  # noqa
    except ImportError:
        AutoWebSocketsProtocol = None
    else:
        from uvicorn.protocols.websockets.wsproto_impl import WSProtocol

        AutoWebSocketsProtocol = WSProtocol
else:
    from uvicorn.protocols.websockets.websockets_sansio_impl import WebSocketsSansIOProtocol

    AutoWebSocketsProtocol = WebSocketsSansIOProtocol