tcp_sixteen.py

#!/usr/bin/env python
# from book foundations in python network prog
# TCP client and Server that send and receive
# 16 octets
import socket
import sys

s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

HOST = sys.argv.pop() if len(sys.argv) == 3 else '127.0.0.1'
PORT = 1060


def recv_all(sock, length):
    data = ''
    while len(data) < length:
        more = sock.recv(length - len(data))
        if not more:
            raise EOFError('socket closed % d bytes into a\
                           %d-byte message' % (len(data), length))
        data += more
    return data

if sys.argv[1:] == ['server']:
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind((HOST, PORT))
    s.listen(1)
    while True:
        print 'Listening at', s.getsockname()
        sc, sockname = s.accept()
        print 'We have accepted a connection from', sockname
        print 'Socket connects', sc.getsockname(), 'and',
        sc.getpeername()
        message = recv_all(sc, 16)
        print 'The incomming sixteen-octet message says', repr(message)
        sc.sendall('Farewell, client')
        sc.close()
        print 'Reply sent, socket closed'

elif sys.argv[1:] == ['client']:
    s.connect((HOST, PORT))
    print 'Client has been assigned socket name', s.getsockname()
    s.sendall('Hi there server')
    reply = recv_all(s, 16)
    print 'The server said', repr(reply)
    s.close()

else:
    print >>sys.stderr, 'usage: tcp_local.py server|client [host]'