My first GitHub Project: A simple chat script in Python

This post is about a simple project that i uploaded on github. It allows you to chat between multiple computers on the same network.

There is a library named "socket" in Python, that allows you to open ports, listen for requests on these ports and send & receive data between multiple machines using this. A "socket" is basically an end point in a Network. I wrote a couple of scripts that allow you to simply share text messages between multiple machines on the same LAN Network. A '\q' message means quit.

properServer.py:

#!/usr/bin/python

import socket
import sys
import os

def listen1():
	while True:	
		try:
			message1 = connection1.recv(180)
                        
                        if message1 ==  '\q':
                            connection2.send(message1)
                            connection1.shutdown(socket.SHUT_RD | socket.SHUT_WR)		
                            connection2.shutdown(socket.SHUT_RD | socket.SHUT_WR)
                            connection1.close()
                            connection2.close()
                            server.close()
                            print "Connections closed"
                            break

                           
			if message1:
				connection2.send(message1)
				print "message",message1,'sent from client1 to client2'
		
		except:
                    try:
                            connection1.shutdown(socket.SHUT_RD | socket.SHUT_WR)		
                            connection2.shutdown(socket.SHUT_RD | socket.SHUT_WR)
                            connection1.close()
                            connection2.close()
                            server.close()
                            print "An error occured. Connections closed"
                            break
                    except:
                        pass

	
def listen2():
	while True:	
		try:
			message2 = connection2.recv(180)
                        if message2 ==  '\q':
                            connection1.send(message2)
                            connection1.shutdown(socket.SHUT_RD | socket.SHUT_WR)		
                            connection2.shutdown(socket.SHUT_RD | socket.SHUT_WR)
                            connection1.close()
                            connection2.close()
                            server.close()
                            print "Connections closed"
                            break

			if message2 != ' ':
				connection1.send(message2)
				print "message",message2,'sent from client2 to client1'
		
		except:
                    try:
                            connection1.shutdown(socket.SHUT_RD | socket.SHUT_WR)		
                            connection2.shutdown(socket.SHUT_RD | socket.SHUT_WR)
                            connection1.close()
                            connection2.close()
                            server.close()
                            print "An error occured. Connections closed"
                            break
                    except:
                        pass



server = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
server.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR,1)


server_address = ('192.168.1.6',8081)
server.bind(server_address)
print "Server started on port 8081"

server.listen(2)	#listens for connection request from clients
connection1,client_address1 = server.accept()	#accepts a request from client
print 'client1:',connection1.getpeername()

server.listen(2)	#listens for connection request from clients
connection2,client_address2 = server.accept()	#accepts a request from client
print 'client2:',connection2.getpeername()

newpid = os.fork()

if newpid == 0:	#child process
	listen1()
	parentId = os.getppid()
	os.kill(parentId,signal.SIGKILL)

	
else:
	listen2()
	

What this does is, it sets up one of the machines as server, that listens for requests. If a client tries to connect to the machine on that IP Address, it accepts the upcoming request. It then receives a message from one client and sends it to the other. Note that only two clients can be connected at a time. Pretty straightforward. This script can be run on one of the machines on which the client script is running, or a third machine may be used that can be used as a server.

client1.py:

#!/usr/bin/python

import socket
import os
import sys
import signal

client1 = socket.socket(socket.AF_INET,socket.SOCK_STREAM)
client1.connect(('192.168.1.6',8081))	#ip address of machine where server is running

def inp():
	while True:
            try:
		message = raw_input('Me: ')
		if message:
			client1.send(message)					
                        if message == '\q':
                            print ""
                            break
                         	
            except:
                break

def outp():
	while True:
		data = client1.recv(180)
		if data:
                    if data == '\q':
                        print ""
                        break
                    print '\nReceived: ',data
                        

newpid = os.fork()

if newpid == 0:	#child process
	outp()
	parentId = os.getppid()
	os.kill(parentId,signal.SIGKILL)	#kill parent, then exit
	
else:
	inp()
	parentId = os.getpid()  #pid returns own, ppid returns parent's process id
	os.kill(parentId,signal.SIGKILL)

This script sends a connection request to the server and then a simple prompt is displayed, that allows user to type messages. A message is sent when the user presses enter. If a message is received, it is displayed on the same screen. Below are some screenshots of the above setup:

 

System 1(Where properServer.py and one instance of client1.py is running):



System 2 (Where another instance of client1.py is running)



 

You can check out these scripts on my github repository: https://github.com/nikssardana/ChatPython

Any comments, suggestions, improvements are always welcome :)