Linux Programming Interface Listing 57-6: A simple UNIX domain datagram server in Python

session.txt

# The Linux Programming Interface Listing 57-6
$ python ud_ucase_sv.py &
[1] 437
$ python ud_ucase_cl.py  hello world
Server received 5 bytes from /tmp/ud_ucase.452
Response 1 : HELLO
Server received 5 bytes from /tmp/ud_ucase.452
Response 2 : WORLD
$ python ud_ucase_cl.py  'long message'
Server received 10 bytes from /tmp/ud_ucase.763
Response 1 : LONG MESSA
$ kill %1
[1]+  Terminated              python ud_ucase_sv.py

ud_ucase_cl.py

# The Linux Programming Interface Listing 57-6
# Python port of sockets/ud_ucase_cl.c

import os
import socket
import sys

def main():
    pid = os.getpid()
    sfd = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)

    svaddr = '/tmp/ud_ucase'
    claddr = '/tmp/ud_ucase.%s'%pid

    sfd.bind(claddr)
    for idx, arg in enumerate(sys.argv[1:]):
        msg_len = sfd.sendto(arg, svaddr)
        data = sfd.recvfrom(msg_len)
        print 'Response %d : %s' % (idx + 1, data[0])

    os.remove(claddr)

if __name__ == '__main__':
    main()

ud_ucase_sv.py

# The Linux Programming Interface Listing 57-6
# Python port of sockets/ud_ucase_sv.c
import os
import socket
import sys

BUF_SIZE = 10

def main():
    sfd = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)

    svaddr = '/tmp/ud_ucase'

    if os.path.exists(svaddr):
        os.remove(svaddr)

    sfd.bind(svaddr)

    while True:
        data, claddr = sfd.recvfrom(BUF_SIZE)
        print 'Server received %d bytes from %s' % (len(data), claddr)
        msg_len = sfd.sendto(data.upper(), claddr)

    os.remove(svaddr)

if __name__ == '__main__':
    main()