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
' % data)

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