python网络编程 - 简单的时间获取服务器

首先写好服务器，在本程序里的端口指的是自身服务器上的端口号，用于区分同在一个服务器上的其他程序。客户端正是凭借着这个端口号和服务器的ip地址来找到服务器，并对之提出请求。

#!/usr/bin/env python
# UDP Wrong Time Server - Chapter 3 - udptimeserver.py
import socket, traceback, time, struct

host = ''                               # Bind to all interfaces
port = 51423

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind((host, port))
print "Waiting for connections..."

while 1:
    try:
        message, address = s.recvfrom(8192)
        secs = int(time.time())         # Seconds since 1/1/1970
        secs -= 60 * 60 * 24            # Make it yesterday
        secs += 2208988800              # Convert to secs since 1/1/1900
        reply = struct.pack("!I", secs)
        s.sendto(reply, address)
    except (KeyboardInterrupt, SystemExit):
        raise
    except:
        traceback.print_exc()

接下来是写好客户端~   可以看到程序中没有用到connect，而是用了sendto还有recvfrom

#!/usr/bin/env python
# UDP Connectionless Example - Chapter 2 - udptime.py

import socket, sys, struct, time

hostname = '127.0.0.1'
port = 51423

host = socket.gethostbyname(hostname)

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.sendto('', (host, port))

print "Looking for replies; press Ctrl-C to stop."
buf = s.recvfrom(2048)[0]
if len(buf) != 4:
    print "Wrong-sized reply %d: %s" % (len(buf), buf)
    sys.exit(1)

secs = struct.unpack("!I", buf)[0]
secs -= 2208988800
print time.ctime(int(secs))

先在程序所在目录下运行>>>python udptimeserver.py 再运行>>>python udptime.py