Socket woes and signals

[Erik Max Francis]

Craig Findlay wrote:

> The loop is basically the standard:
> 
> while 1:
>         conn, addr = s.accept()
>         data = conn.recv(bufsize)
>         if not data: break
>         do something with data
> conn.close()
> 
> Q. This is fine if the client closes the connection, but how do I
> break out of the look in response to say a signal?

You can change the signal handler to raise a custom exception which you
can then catch and act on.

> If I force the loop to end ungracefully, the socket is left hanging
> and I have to reboot the machine to free it up.

It takes a few minutes for it to clear, but you won't need to actually
reboot to free it up.

> But the code normally
> stops at the accept line until a connection is accepted, so how do I
> close the socket properly in that state?

If that's all you need, there's an easier way.  AFter you create the
socket, call:

    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)

Now you won't have to wait to rebind to the address.

-- 
 Erik Max Francis / max at alcyone.com / http://www.alcyone.com/max/
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