仅当client.py运行时，Python Socket errno 10054

Question

There are some other posts about this issue but none did help me with mine. I'm trying to build a total simple server - client relationship in python

server.py

#!/usr/bin/python
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.bind(("127.0.0.1",8889))
s.listen(1)   
try:

    while True:
        client, add = s.accept()
        data = client.recv(1024)
        if not data:
            print 'No data'
        print data

finally:
    s.close()

client.py

#!/usr/bin/python
import socket

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
s.connect(("127.0.0.1",8889))


try:
    while True:
        message = 'Foo'
        s.send(message)
        ans = s.recv(1024)
        print ans
finally:
    s.close()

I start by running the server first, but when I try to run the client I'm getting this Errno 10054 --> An existing connection was forcibly closed by the remote host While request the browser with the ip and the related port, I receive some data. I'm quiet new to networking, so please explain what might be obvious wrong in my code.

EDIT* Main issue is, that the client is somehow wrong, because it returns also an empty string on recv

Thank you in advance

Answer 1

I am guessing:

The server accepts one socket and then does

    client, add = s.accept()
    data = client.recv(1024)
    ...
    client, add = s.accept()

The client does this in the mean time:

s.send(message)
ans = s.recv(1024) # blocks until timeout

If now an other client connects to the server then client is replaced, the socket garbage collected and closed. s.recv(1024) will then tell that the connection is reset.

Have a look at import select or twisted (google around) to handle multiple connections at once.

Answer 2

Main issue is, that the client is somehow wrong, because it returns also an empty string on recv

The client isn't receiving anything from the server because the server is not sending anything.

On the server side, after print data , adding client.send(data) will send the string back to the client.