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。

一、Python socket编程

面向连接的TCP socket编程：

 1 # -*- coding: utf-8 -*-
 2
 3 from socket import *
 4 from time import ctime
 5
 6 # Address and Port
 7 HOST = ‘‘
 8 PORT = 21567
 9 ADDR = (HOST, PORT)
10
11 # BuffSize
12 BUFSIZ = 1024
13
14 # build socket
15 tcpSerSock = socket(AF_INET, SOCK_STREAM)
16 # bind socket
17 tcpSerSock.bind(ADDR)
18 # listen 5 client
19 tcpSerSock.listen(5)
20
21 try:
22     while True:
23         print ‘waiting for connection...‘
24         # build client socket
25         tcpCliSock, addr = tcpSerSock.accept()
26         print ‘...connect from:‘, addr
27
28         # accept data and process
29         while True:
30             data = tcpCliSock.recv(BUFSIZ)
31             if not data:
32                 break
33             tcpCliSock.send(‘[%s] %s‘ % (ctime(), data))
34
35             # close client socket
36             tcpCliSock.close()
37 except EOFError, KeyboardInterrupt:
38     tcpSerSock.close()

 1 # -*- coding:utf-8 -*-
 2
 3 from socket import *
 4
 5 # Address and Port
 6 HOST = ‘127.0.0.1‘
 7 PORT = 21567
 8 ADDR = (HOST, PORT)
 9
10 # BufferSize
11 BUFSIZ = 1024
12
13 #build socket
14 tcpCliSocket = socket(AF_INET, SOCK_STREAM)
15 tcpCliSocket.connect(ADDR)
16
17 while True:
18     data = raw_input(‘> ‘)
19     if not data:
20         break
21     # send data
22     tcpCliSocket.send(data)
23     # recv data
24     data = tcpCliSocket.recv(BUFSIZ)
25     if not data:
26         break
27     # show data
28     print data
29 tcpCliSocket.close()

无连接的UDP socket编程

 1 # -*- coding: utf-8 -*-
 2
 3 from socket import *
 4 from time import ctime
 5
 6 # Address and Port
 7 HOST = ‘‘
 8 PORT = 8000
 9 ADDR = (HOST, PORT)
10
11 # BufferSize
12 BUFFSIZE = 1024
13 # build socket
14 udpSerSock = socket(AF_INET, SOCK_DGRAM)
15 # bind socket
16 udpSerSock.bind(ADDR)
17
18 try:
19     while True:
20         print ‘waiting the message...‘
21         data, addr = udpSerSock.recvfrom(BUFFSIZE)
22         print ‘received the message: ‘+data+‘ from: ‘, addr
23         udpSerSock.sendto(‘[%s] %s‘ % (ctime(), data), addr)
24 except EOFError, KeyboardInterrupt:
25     udpSerSock.close()

 1 # -*- coding: utf-8 -*-
 2
 3 from socket import *
 4
 5 # Address and Port
 6 HOST = ‘localhost‘
 7 PORT = 8000
 8 ADDR = (HOST, PORT)
 9
10 # BufferSize
11 BUFSIZ = 1024
12
13 # build socket
14 udpCliSock = socket(AF_INET, SOCK_DGRAM)
15
16 while True:
17     data = raw_input(‘> ‘)
18     udpCliSock.sendto(data, ADDR)
19     data = udpCliSock.recvfrom(BUFSIZ)
20     if not data:
21         break
22     print data
23 udpCliSock.close()

二、基于封装类SocketServer的网络编程

 1 # -*- coding: utf-8 -*-
 2
 3 from SocketServer import TCPServer as TCP, StreamRequestHandler as SRH
 4 from time import ctime
 5
 6 # Address and Port
 7 HOST = ‘‘
 8 PORT = 21567
 9 ADDR = (HOST, PORT)
10
11 # BuffSize
12 BUFSIZ = 1024
13
14 # build RequestHandler
15 class MyRequestHandler(SRH):
16     def handle(self):
17         print ‘...connected from: ‘, self.client_address
18         self.wfile.write(‘[%s] %s‘ % (ctime(), self.rfile.readline()))
19
20 # build TCPServer
21 TCPServ = TCP(ADDR, MyRequestHandler)
22 print ‘waiting for connection...‘
23 # loop to process
24 TCPServ.serve_forever()

 1 # -*- coding:utf-8 -*-
 2
 3 from socket import *
 4
 5 # Address and Port
 6 HOST = ‘127.0.0.1‘
 7 PORT = 21567
 8 ADDR = (HOST, PORT)
 9
10 # BufferSize
11 BUFSIZ = 1024
12
13 while True:
14     # note: SocketServer 的请求处理器的默认行为是接受连接，
15     # 得到请求，然后就关闭连接，所以需要多次连接
16     tcpCliSock = socket(AF_INET, SOCK_STREAM)
17     tcpCliSock.connect(ADDR)
18
19     # process data
20     data = raw_input(‘> ‘)
21     if not data:
22         break
23     tcpCliSock.send(‘%s\r\n‘ % data)
24
25     data = tcpCliSock.recv(BUFSIZ)
26     if not data:
27         break
28     print data.strip()
29     tcpCliSock.close()