Python. Socket closes after one input

Question

I am doing an simple Python socket server and client that need to be able to receive few inputs and not losing connection. I can input one command but after receiving the reply the connection is lost. How can i keep it alive?

Client code

import socket  
import sys 
try:
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
except sockets.error , msg:
    print 'Failed to create socket, Error code:' + str(msg[0]) + ' , Error message :' +     msg[1]
    sys.exit()

print 'Socket Created'

host = '127.0.0.1'
port = 8888
try:
    remote_ip = socket.gethostbyname( host )

except socket.gaierror:

    print 'Hostname could not be resolved. Exiting'
    sys.exit()

print 'Ip address of ' + host + ' is ' + remote_ip

s.connect((remote_ip , port))

print 'Socket Connected to ' + host + ' on ip ' + remote_ip

message = raw_input('Sladu inn skipun :')

try :
   s.sendall(message)
except socket.error:
   print 'Send failed'
   sys.exit()

print 'Message send successfully'

reply = s.recv(4096)

print reply

s.close()

Server code

#!/usr/bin/env python
# -*- coding: utf-8 -*- 
import socket
import sys
from thread import *
import glob

HOST = ''   # Symbolic name meaning all available interfaces
PORT = 8888 # Arbitrary non-privileged port

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
print 'Socket created'

try:
    s.bind((HOST, PORT))
except socket.error , msg:
    print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
    sys.exit()

print 'Socket bind complete'


s.listen(10)
print 'Socket now listening'


def clientthread(conn):

    while True:
        data = conn.recv(1024)
        if data == "show dir":
            reply = glob.glob('*.*')
        else: 
           reply ="Þessi skipun hefur ekki verið forrituð"
           if not data:
              break

        conn.send(str(reply))


while 1:

    conn, addr = s.accept()
    print 'Connected with ' + addr[0] + ':' + str(addr[1])


    start_new_thread(clientthread ,(conn,))

s.close()

The indentation in your example is all messed up. It's impossible to know for sure what code belongs to what block. — Bryan Oakley
– Bryan Oakley, Commented Sep 17, 2013 at 22:24
Thank you, fixed the formatting. Hope it makes more sense now. — Hundurinn Nero
– Hundurinn Nero, Commented Sep 17, 2013 at 22:32
You can have an else statement on a while loop in python? Eww. Here's to hoping your indentation isn't fixed. — xaxxon
– xaxxon, Commented Sep 17, 2013 at 22:38
@xaxxon: Yes, you can have an else on a while loop, and it's very useful. (Well, more often useful with for than while, but then for is more often useful than for anyway…) It's explained in the tutorial, but basically, it lets you use break without needing the found = True flag or other out-of-band way of distinguishing "broke out early because of success" vs. "finished the loop because we never found anything" that's so common in C. — abarnert
– abarnert, Commented Sep 18, 2013 at 0:44

aychedee · Accepted Answer · 2013-09-17 23:03:51Z

4

Your server code looks okay. But your client is only sending one message and then exiting. Which closes the connection.

Try something like this in your client code:

while True:
    message = raw_input('Sladu inn skipun :')
    try :
        s.sendall(message)
        print s.recv(1024)
    except socket.error:
        print 'Send failed'
        sys.exit()

edited Sep 17, 2013 at 23:03

answered Sep 17, 2013 at 22:43

aychedee

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2 Comments

Manoj Pandey Over a year ago

+1. I would also add the "reply = s.recv(4096)" in the same while-loop since you are expecting the server to send a response too.

aychedee Over a year ago

True, Manoj, @HundurinnNero: If the answer worked for you it's a good idea to accept it as the correct one. It helps future searchers.

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