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Chat server in python

# chat_server.py
import sys
import socket
import select
HOST = ''
SOCKET_LIST = []
RECV_BUFFER = 4096
PORT = 9009
def chat_server():
 server_socket=socket.socket(socket.AF_INET,socket.SOCK_STREAM)
 server_socket.setsockopt(socket.SOL_SOCKET,socket.SO_REUSEADDR, 1)
 server_socket.bind((HOST, PORT))
 server_socket.listen(10)
# add server socket object to the list of readable connections
SOCKET_LIST.append(server_socket)
print "Chat server started on port " + str(PORT)
while 1:
   # get the list sockets which are ready to be read through select
   # 4th arg, time_out  = 0 : poll and never block
 ready_to_read,ready_to_write,in_error=select.select(SOCKET_LIST,[],[],0)
for sock in ready_to_read:
            # a new connection request recieved
            if sock == server_socket:
                sockfd, addr = server_socket.accept()
                SOCKET_LIST.append(sockfd)
        print "Client (%s, %s) connected" % addr
               
        broadcast(server_socket, sockfd, "[%s:%s] entered our chatting room\n" % addr)
           
            # a message from a client, not a new connection
         else:
                # process data recieved from client,
         try:
              # receiving data from the socket.
              data = sock.recv(RECV_BUFFER)
           if data:
               # there is something in the socket
                broadcast(server_socket, sock, "\r" + '[' + str(sock.getpeername()) + '] ' + data) 
            else:
                # remove the socket that's broken    
                if sock in SOCKET_LIST:
                    SOCKET_LIST.remove(sock)
                 # at this stage, no data means probably the connection has been broken
               broadcast(server_socket, sock, "Client (%s, %s) is offline\n" % addr)
                # exception
                except:
                broadcast(server_socket, sock, "Client (%s, %s) is offline\n" % addr)
                    continue

    server_socket.close()
*****************************************************************   
# broadcast chat messages to all connected clients
def broadcast (server_socket, sock, message):
    for socket in SOCKET_LIST:
        # send the message only to peer
        if socket != server_socket and socket != sock :
            try :
                socket.send(message)
            except :
                # broken socket connection
                socket.close()
                # broken socket, remove it
                if socket in SOCKET_LIST:
                    SOCKET_LIST.remove(socket)

if __name__ == "__main__":

    sys.exit(chat_server())  
#**********************************************************    
# chat_client.py
 
import sys
import socket
import select
 def chat_client():
    if(len(sys.argv) < 3) :
        print 'Usage : python chat_client.py hostname port'
        sys.exit()
 
    host = sys.argv[1]
    port = int(sys.argv[2])
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.settimeout(2)
     # connect to remote host
    try :
        s.connect((host, port))
    except :
        print 'Unable to connect'
        sys.exit()
        print 'Connected to remote host. You can start sending messages'
    sys.stdout.write('[Me] '); sys.stdout.flush()
    while 1:
        socket_list = [sys.stdin, s]
         
        # Get the list sockets which are readable
        ready_to_read,ready_to_write,in_error = 
                               select.select(socket_list , [], [])
         
        for sock in ready_to_read:             
            if sock == s:
                # incoming message from remote server, s
                data = sock.recv(4096)
                if not data :
                    print '\nDisconnected from chat server'
                    sys.exit()
                else :
                    #print data
                    sys.stdout.write(data)
                    sys.stdout.write('[Me] '); sys.stdout.flush()     
            else :
                # user entered a message
                msg = sys.stdin.readline()
                s.send(msg)
                sys.stdout.write('[Me] '); sys.stdout.flush() 
 
if __name__ == "__main__":
    sys.exit(chat_client())


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