[Tutor] Talking to UDPServer

[Kent Johnson]

Carroll, Barry wrote:
> Yes, that is exactly what I want.  I need to write a program that 
> communicates with an existing server, using the UDP protocol.  This is 
> my first time writing such a program, and I need help getting started. 

Here is an example from Python Network Programming, by John Goerzen. It opens a UDP port, sends a message, then echoes any received text to the console. There is no higher-level support built in to Python, you just open a datagram socket and push data out. Google for "Python udp" for more examples.

Kent

#!/usr/bin/env python
# UDP Example - Chapter 2

import socket, sys, time

host = sys.argv[1]
textport = sys.argv[2]

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
try:
    port = int(textport)
except ValueError:
    # That didn't work.  Look it up instread.
    port = socket.getservbyname(textport, 'udp')

s.connect((host, port))
print "Enter data to transmit: "
data = sys.stdin.readline().strip()
s.sendall(data)
s.shutdown(1)
print "Looking for replies; press Ctrl-C or Ctrl-Break to stop."
while 1:
    buf = s.recv(2048)
    if not len(buf):
        break
    print "Received: %s" % buf