NOS Lab

chat_client.py

import socket, select, sys

host = "localhost"
port = 9009

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((host, port))

while 1:
    read, write, error = select.select([sock, sys.stdin], [], [])
    for s in read:
        if s == sock:
            data = s.recv(1024)
            print data
        if s == sys.stdin:
            data = sys.stdin.readline()
            sys.stdout.flush()
            sock.send(data)

chat_server.py

import socket, select

host = "localhost"
port = 9009

server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server_socket.bind((host, port))
server_socket.listen(10)

sock_list = []

sock_list.append(server_socket)


def broadcast(sock, message):
    print "Broadcasting...", message
    for s in sock_list:
        try:
            if s != server_socket and s != sock:
                s.send(message)
        except:
            broadcast(sock, "Removing: " + str(sock))
            s.close()
            if s in sock_list:
                sock_list.remove(s)


while 1:
    # inside loop as sock_list can change
    read, write, error = select.select(sock_list, [], [])
    for sock in read:
        if sock == server_socket:
            # new conn
            cs, addr = server_socket.accept()
            sock_list.append(cs)
            broadcast(cs, "JOIN: " + str(cs))
        else:
            try:
                data = sock.recv(1024)
                print data
                if data:
                    broadcast(sock, str(sock) + " : " + data)
                else:
                    broadcast(sock, "Removing: " + str(sock))
                    if sock in sock_list:
                        sock_list.remove(sock)
            except:
                continue

fork_and_pipe.py

# it works but don't know if its the right way to do it

import os

# create two pipes
r, w = os.pipe()
r2, w2 = os.pipe()

# fork a process
# the proces with pid will be the parent proces
pid = os.fork()

if pid:  # parent
    os.close(r)
    os.close(w2)
    w = os.fdopen(w, 'w')
    w.write("snow")
    w.close()
    r2 = os.fdopen(r2)
    print r2.read()
else:  # child
    os.close(w)
    os.close(r2)
    r = os.fdopen(r)
    data = r.read()
    print data
    w2 = os.fdopen(w2, 'w')
    w2.write("ponies")
    w2.close()