TCP Keep Alive doesn't seem to be enabled by default

[ltshb]

In the documentation, it stated the TCP Keep Alive are enabled by default when using requests, but looking at the code it doesn't seem to be the case.

Expected Result

TCP Keep Alive be enable by default.

Actual Result

I could not find anywhere in the code where the TCP Keep Alive are enabled. Maybe I missed something ? In the urllib3 library it seems to me that TCP Keep Alive are not enabled by default, see https://github.com/urllib3/urllib3/blob/5a24dc55d86e4c5ca7fe0bd496da768caf617591/src/urllib3/connection.py#L109.

It would also be good to have the possibility to pass socket arguments to the HTTPAdapter, for my use case where I needed TCP keep alive, I had to overwrite the HTTPAdapter like this in order to pass socket options:

class HTTPKeepAliveAdapter(HTTPAdapter):

    def __init__(self, max_retries):
        self._pool_kwargs = {
            'socket_options':
                HTTPConnection.default_socket_options + [
                    (socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1),  # enable keep alive
                    (socket.SOL_TCP, socket.TCP_KEEPIDLE, 120),  # idle time 120s
                    (socket.SOL_TCP, socket.TCP_KEEPINTVL, 120)
                ]  # interval time 120s
        }
        super().__init__(pool_connections=40, pool_maxsize=60, max_retries=max_retries)
        self.init_poolmanager(
            self._pool_connections, self._pool_maxsize, block=self._pool_block, **self._pool_kwargs
        )

    def __setstate__(self, state):
        super().__init__(state)

        self.init_poolmanager(
            self._pool_connections, self._pool_maxsize, block=self._pool_block, **self._pool_kwargs
        )

But I may have missed something as well ?

[sigmavirus24]

If you'd like to specify custom socket options more conveniently, https://toolbelt.readthedocs.io/en/latest/adapters.html#socketoptionsadapter

I believe TCP Keep-Alive caused more issues than benefits but the references in the docs were never removed. There's also: https://toolbelt.readthedocs.io/en/latest/adapters.html#requests_toolbelt.adapters.socket_options.TCPKeepAliveAdapter to make this easier for folks who know they need it