Demo/sockets/udpecho.py

   1 #! /usr/bin/env python
   2
   3 # Client and server for udp (datagram) echo.
   4 #
   5 # Usage: udpecho -s [port]            (to start a server)
   6 # or:    udpecho -c host [port] <file (client)
   7
   8 import sys
   9 from socket import *
  10
  11 ECHO_PORT = 50000 + 7
  12 BUFSIZE = 1024
  13
  14 def main():
  15     if len(sys.argv) < 2:
  16         usage()
  17     if sys.argv[1] == '-s':
  18         server()
  19     elif sys.argv[1] == '-c':
  20         client()
  21     else:
  22         usage()
  23
  24 def usage():
  25     sys.stdout = sys.stderr
  26     print 'Usage: udpecho -s [port]            (server)'
  27     print 'or:    udpecho -c host [port] <file (client)'
  28     sys.exit(2)
  29
  30 def server():
  31     if len(sys.argv) > 2:
  32         port = eval(sys.argv[2])
  33     else:
  34         port = ECHO_PORT
  35     s = socket(AF_INET, SOCK_DGRAM)
  36     s.bind(('', port))
  37     print 'udp echo server ready'
  38     while 1:
  39         data, addr = s.recvfrom(BUFSIZE)
  40         print 'server received %r from %r' % (data, addr)
  41         s.sendto(data, addr)
  42
  43 def client():
  44     if len(sys.argv) < 3:
  45         usage()
  46     host = sys.argv[2]
  47     if len(sys.argv) > 3:
  48         port = eval(sys.argv[3])
  49     else:
  50         port = ECHO_PORT
  51     addr = host, port
  52     s = socket(AF_INET, SOCK_DGRAM)
  53     s.bind(('', 0))
  54     print 'udp echo client ready, reading stdin'
  55     while 1:
  56         line = sys.stdin.readline()
  57         if not line:
  58             break
  59         s.sendto(line, addr)
  60         data, fromaddr = s.recvfrom(BUFSIZE)
  61         print 'client received %r from %r' % (data, fromaddr)
  62
  63 main()