Initial revision

Demo/sockets/udpecho.py

@@ -0,0 +1,63 @@
+#! /usr/local/python
+
+# Client and server for udp (datagram) echo.
+#
+# Usage: udpecho -s [port]            (to start a server)
+# or:    udpecho -c host [port] <file (client)
+
+import sys
+from socket import *
+
+ECHO_PORT = 50000 + 7
+BUFSIZE = 1024
+
+def main():
+	if len(sys.argv) < 2:
+		usage()
+	if sys.argv[1] = '-s':
+		server()
+	elif sys.argv[1] = '-c':
+		client()
+	else:
+		usage()
+
+def usage():
+	sys.stdout = sys.stderr
+	print 'Usage: udpecho -s [port]            (server)'
+	print 'or:    udpecho -c host [port] <file (client)'
+	sys.exit(2)
+
+def server():
+	if len(sys.argv) > 2:
+		port = eval(sys.argv[2])
+	else:
+		port = ECHO_PORT
+	s = socket(AF_INET, SOCK_DGRAM)
+	s.bind('', port)
+	print 'udp echo server ready'
+	while 1:
+		data, addr = s.recvfrom(BUFSIZE)
+		print 'server received', `data`, 'from', `addr`
+		s.sendto(data, addr)
+
+def client():
+	if len(sys.argv) < 3:
+		usage()
+	host = sys.argv[2]
+	if len(sys.argv) > 3:
+		port = eval(sys.argv[3])
+	else:
+		port = ECHO_PORT
+	addr = host, port
+	s = socket(AF_INET, SOCK_DGRAM)
+	s.bind('', 0)
+	print 'udp echo client ready, reading stdin'
+	while 1:
+		line = sys.stdin.readline()
+		if not line:
+			break
+		s.sendto(line, addr)
+		data, fromaddr = s.recvfrom(BUFSIZE)
+		print 'client received', `data`, 'from', `fromaddr`
+
+main()