python网络编程初级

网络编程的专利权应该属于Unix，各个平台（如windows、Linux等）、各门语言（C、C++、Python、Java等）所实现的符合自身特性的语法都大同小异。在我看来，懂得了Unix的socket网络编程，其他的形式的网络编程方法也就知道了。这句话说得还不太严谨。准确的应该说成懂得了socket编程的原理，网络编程也就知道了，不同之处就在于每个平台，每个语言都有自己专享的语法，我们直接灵活套用就行了。

下面是用python实现的最基本的网络编程的例子，即依托于客户端-服务器的架构，实现客户端与服务器之间的单向“数据流通”。我们分别用两个方法来实现，一个方法是最原始的socket编程，另一个方法是利用python的面向对象对第一种方法进行封装实现，目的是减少实现透明性，便于快速开发。

要求：客户端输入数据，发送到服务端，服务器端生成（时间戳+数据）的封装数据回应客户端。由于socket编程包括两种：面向连接的和无连接的，这两种分别对应TCP数据流和UDP数据报文。所以，我们两种方法都进行实现。

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一、Python socket编程

面向连接的TCP socket编程：

 # -*- coding: utf-8 -*-

 from socket import *
 from time import ctime 

 # Address and Port
 HOST = ''
 PORT = 21567
 ADDR = (HOST, PORT)

 # BuffSize
 BUFSIZ = 1024

 # build socket
 tcpSerSock = socket(AF_INET, SOCK_STREAM)
 # bind socket
 tcpSerSock.bind(ADDR)
 # listen 5 client
 tcpSerSock.listen(5)

 try:
     while True:
         print 'waiting for connection...'
         # build client socket
         tcpCliSock, addr = tcpSerSock.accept()
         print '...connect from:', addr

         # accept data and process
         while True:
             data = tcpCliSock.recv(BUFSIZ)
             if not data:
                 break
             tcpCliSock.send('[%s] %s' % (ctime(), data))

             # close client socket
             tcpCliSock.close()
 except EOFError, KeyboardInterrupt:
     tcpSerSock.close()

 # -*- coding:utf-8 -*-

 from socket import *

 # Address and Port
 HOST = '127.0.0.1'
 PORT = 21567
 ADDR = (HOST, PORT)

 # BufferSize
 BUFSIZ = 1024

 #build socket
 tcpCliSocket = socket(AF_INET, SOCK_STREAM)
 tcpCliSocket.connect(ADDR)

 while True:
     data = raw_input('> ')
     if not data:
         break
     # send data
     tcpCliSocket.send(data)
     # recv data
     data = tcpCliSocket.recv(BUFSIZ)
     if not data:
         break
     # show data
     print data
 tcpCliSocket.close()

无连接的UDP socket编程

 # -*- coding: utf-8 -*-

 from socket import *
 from time import ctime 

 # Address and Port
 HOST = ''
 PORT = 8000
 ADDR = (HOST, PORT)

 # BufferSize
 BUFFSIZE = 1024
 # build socket
 udpSerSock = socket(AF_INET, SOCK_DGRAM)
 # bind socket
 udpSerSock.bind(ADDR)

 try:
     while True:
         print 'waiting the message...'
         data, addr = udpSerSock.recvfrom(BUFFSIZE)
         print 'received the message: '+data+' from: ', addr
         udpSerSock.sendto('[%s] %s' % (ctime(), data), addr)
 except EOFError, KeyboardInterrupt:
     udpSerSock.close()

 # -*- coding: utf-8 -*-

 from socket import *

 # Address and Port
 HOST = 'localhost'
 PORT = 8000
 ADDR = (HOST, PORT)

 # BufferSize
 BUFSIZ = 1024

 # build socket
 udpCliSock = socket(AF_INET, SOCK_DGRAM)

 while True:
     data = raw_input('> ')
     udpCliSock.sendto(data, ADDR)
     data = udpCliSock.recvfrom(BUFSIZ)
     if not data:
         break
     print data
 udpCliSock.close()

二、基于封装类SocketServer的网络编程

 # -*- coding: utf-8 -*-

 from SocketServer import TCPServer as TCP, StreamRequestHandler as SRH
 from time import ctime 

 # Address and Port
 HOST = ''
 PORT = 21567
 ADDR = (HOST, PORT)

 # BuffSize
 BUFSIZ = 1024

 # build RequestHandler
 class MyRequestHandler(SRH):
     def handle(self):
         print '...connected from: ', self.client_address
         self.wfile.write('[%s] %s' % (ctime(), self.rfile.readline()))

 # build TCPServer
 TCPServ = TCP(ADDR, MyRequestHandler)
 print 'waiting for connection...'
 # loop to process
 TCPServ.serve_forever()

 # -*- coding:utf-8 -*-

 from socket import *

 # Address and Port
 HOST = '127.0.0.1'
 PORT = 21567
 ADDR = (HOST, PORT)

 # BufferSize
 BUFSIZ = 1024

 while True:
     # note: SocketServer 的请求处理器的默认行为是接受连接，
     # 得到请求，然后就关闭连接，所以需要多次连接
     tcpCliSock = socket(AF_INET, SOCK_STREAM)
     tcpCliSock.connect(ADDR)

     # process data
     data = raw_input('> ')
     if not data:
         break
     tcpCliSock.send('%s\r\n' % data)

     data = tcpCliSock.recv(BUFSIZ)
     if not data:
         break
     print data.strip()
     tcpCliSock.close()