How to use python socket.settimeout() properly

Question

As far as I know, when you call socket.settimeout(value) and you set a float value greater than 0.0, that socket will raise a scocket.timeout when a call to, fo

Answer 1

Timeout applies to a single call to socket read/write operation. So next call it will be 20 seconds again.

A) To have a timeout shared by several consequential calls, you'll have to track it manually. Something along these lines:

deadline = time.time() + 20.0
while not data_received:
    if time.time() >= deadline:
        raise Exception() # ...
    socket.settimeout(deadline - time.time())
    socket.read() # ...

B) Any code that's using a socket with a timeout and isn't ready to handle socket.timeout exception will likely fail. It is more reliable to remember the socket's timeout value before you start your operation, and restore it when you are done:

def my_socket_function(socket, ...):
    # some initialization and stuff
    old_timeout = socket.gettimeout() # Save
    # do your stuff with socket
    socket.settimeout(old_timeout) # Restore
    # etc

This way, your function will not affect the functioning of the code that's calling it, no matter what either of them do with the socket's timeout.