卡在循环python中

Question

I am creating a chat server in python and got quite far as a noob in the language. I am having 1 problem at the moment which I want to solve before I go further, but I cannot seem to find how to get the problem solved.

It is about a while loop that continues..

in the below code is where it goes wrong

while 1:
    try:
        data = self.channel.recv ( 1024 )
        print "Message from client: ", data
        if "exit" in data:
            self.channel.send("You have closed youre connection.\n")
            break
    except KeyboardInterrupt:
        break
    except:
        raise

When this piece of code get executed, on my client I need to enter "exit" to quit the connection. This works as a charm, but when I use CTRL+C to exit the connection, my server prints "Message from client: " a couple of thousand times.

where am I going wrong?

Answer 1

You're pressing Ctrl-C on the client side. This causes the server's self.channel to get closed.

Since calling recv() on a closed channel immediately returns a blank string, your server code gets stuck in an infinite loop.

To fix this, add the following line to your server code:

data = self.channel.recv ( 1024 )
if not data: break # <<< ADD THIS

Or, as suggested by @sr2222, you can combine both this and your current check into one:

if not data or 'exit' in data: 

This will exit the loop if the channel has been closed.