Python: Stop the socket-receiving-process

Question

I receive data from some device via socket-module. But after some time the device stops sending packages. Then I want to interupt the for-loop. While True doesn't work, because he receives more then 100 packages. How can I stop this process? s stands for socket.

...
for i in range(packages100):
    data = s.recv(4)
    f.write(data)
...

Edit: I think socket.settimeout() is part of the solution. See also: How to set timeout on python's socket recv method?

Is not there a way to find out how many packages the client will want to recv? — bpgergo, May 11 '11 at 12:24
Stopping the process is not the problem. The problem is deciding when to do so. What are the criteria? — Kylotan, May 11 '11 at 13:34
I want to stop the process after one second without receiving data. — kame, May 11 '11 at 13:48

score 3 · Answer 1 · answered May 11 '11 at 12:21

If your peer really just stops sending data, as opposed to closing the connection, this is tricky and you'll be forced to resort to asynchronous reading from this socket.

Put it in asynchronous mode (the docs and Google are your friends), and try to read it each time, instead of the blocking read. You can then just stop "trying" anytime you wish. Note that by nature of async IO your code will be a bit different - you will no longer be able to assume that once recv returns, it actually read some data.

score 2 · Answer 2 · answered May 11 '11 at 12:11

2

while 1:
    data = conn.recv(4)
    if not data: break
    f.write(data)

Also, example in python docs

answered May 11 '11 at 12:11

bpgergo

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Ahh, I see. So "the device stops sending packages" is not equivalent to closing the con. – bpgergo May 11 '11 at 12:23
1

Well, maybe and maybe not, I can't be sure what the OP means. I just wanted to point out the difference – Eli Bendersky May 11 '11 at 12:24

Python: Stop the socket-receiving-process

2 Answers2