Function get_proxy

src/websockets/proxy.py:98–131

Return the proxy to use for connecting to the given WebSocket URI, if any.

(uri: WebSocketURI)

def get_proxy(uri: WebSocketURI) -> str | None:
    """
    Return the proxy to use for connecting to the given WebSocket URI, if any.

    """
    if urllib.request.proxy_bypass(f"{uri.host}:{uri.port}"):
        return None

    # According to the _Proxy Usage_ section of RFC 6455, use a SOCKS5 proxy if
    # available, else favor the proxy for HTTPS connections over the proxy for
    # HTTP connections.

    # The priority of a proxy for WebSocket connections is unspecified. We give
    # it the highest priority. This makes it easy to configure a specific proxy
    # for websockets.

    # getproxies() may return SOCKS proxies as {"socks": "http://host:port"} or
    # as {"https": "socks5h://host:port"} depending on whether they're declared
    # in the operating system or in environment variables.

    proxies = urllib.request.getproxies()
    if uri.secure:
        schemes = ["wss", "socks", "https"]
    else:
        schemes = ["ws", "socks", "https", "http"]

    for scheme in schemes:
        proxy = proxies.get(scheme)
        if proxy is not None:
            if scheme == "socks" and proxy.startswith("http://"):
                proxy = "socks5h://" + proxy[7:]
            return proxy
    else:
        return None


def prepare_connect_request(