python 网络编程常用代码段

服务器端代码:

# -*- coding: cp936 -*-
import socket 
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)#初始化socket 
sock.bind(("127.0.0.1", 8001))#绑定本机地址，8001端口
sock.listen(5)#等待客户连接 
while True:
  print "waiting client connection..."
  connection,address = sock.accept()#接收客户连接请求
  print "a client have connected..."
  while True:
    try: 
      connection.settimeout(5) #设置超时时间
      buf = connection.recv(1024) #接收数据
      if buf == "1": 
        connection.send("you have send me 1!welcome to server!")
      elif buf=="2":
        connection.send("you have send me 2!I have recv!")
      elif buf=="3":
        connection.send("close the connection!")
        break
      else: 
        connection.send("unknow command!") 
    except socket.timeout: 
      print "time out" 
  connection.close()
  print "a client exit..."

客户器端代码：

import socket 
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
sock.connect(("127.0.0.1", 8001)) 
import time 
time.sleep(2)
while True:
  data=raw_input("input command:");
  sock.send(data)
  print sock.recv(1024)
  if data=="3":
    break
sock.close()

1.首先开两个IDLE，分别打开服务器端和客户器端代码。
2.F5运行服务器端代码，会出现waiting client connection...
3.F5运行客户端代码，会出现input command: ；
4.这时服务器和客户端就连接上了，可以正常的通信啦，如图：

5.再次运行服务器端代码时会出现错误，这时可以通过任务管理器，将其中的pythonw.exe进程结束，重新打开，编译就可以啦！

客户端：

import socket
s=socket.socket()
host = socket.gethostname()
port = 1234
s.connect((host, port))
print s.recv(1024)

服务端：

import socket
s = socket.socket()
host = socket.gethostname()
port = 1234
s.bind((host, port))
 
s.listen(5)
while True:
 c, addr = s.accept()
 print 'Got connection from', addr
 c.send('Thank you for connecting')
 c.close()

http编程

from urllib import urlopen
webpage = urlopen('http://www.python.org')

加上正规表达式

import re
text = webpage.read()
m = re.search('<a href="([^"]+)" .*?>about</a>', text, re.IGNORECASE)
m.group(1)

urllib
urllib2

一个基于SocketServer的小型服务器例子：

from SocketServer import TCPServer, StreamRequestHandler
>>> class Handler(StreamRequestHandler):
	def handle(self):
		addr = self.request.getpeername()
		print 'Got connection from', addr
		self.wfile.write('Thank you for connecting')
 
>>> server = TCPServer(('',1234), Handler)
>>> server.serve_forever()

使用SocketServer进行分叉和线程处理
分叉Server:

from SocketServer import TCPServer,ForkingMinIn, StreamRequestHandler
class Server(ForkingMinIn, TCPServer):pass
class Handler(StreamRequestHandler):
 def handle(self):
  addr = self.request.getpeername()
  print 'Got connection from',addr
  self.wfile.write('Thank you for connection')
server = Server(('',1234),Handler)
server.serve_forever()

线程Server:

from SocketServer import TCPServer, ThreadingMixIn, StreamRequestHandler
class Server(ThreadingMixIn, TCPServer):pass
class Handler(StreamRequestHandler):
 def handle(self):
  addr = self.request.getpeername()
  print 'Got connection from',addr
  self.wfile.write('Thank you for connecting')
server = Server(('',1234),Handler)
server.serve_forever()

带有select和pool的异步I/O
select服务：

import socket, select
s = socket.socket()
host = socket.gethostname()
prot = 1234
s.bind((host,port))
 
s.listen(5)
inputs = [s]
while True:
 rs,ws,es = select.select(inputs,[],[])
 for r in rs:
  if r is s:
  c, addr = s.accept()
  print 'Got connection from',addr
  inputs.append(c)
 else:
  try:
   data = r.recv(1024)
   disconnected = not data
  except socket.error:
   disconnected = True
   
  if disconnected:
   print r.getpeername(), 'disconnected'
   inputs.remove(r)
  else:
   print data

pool服务器：

import socket, select
s = socket.socket()
host = socket.gethostname()
port = 1234
s.bind((host, port))
 
fdmap = {s.fileno():s}
 
s.listen(5)
p = select.poll()
p.register(s)
while True:
 events = p.poll()
 for fd, event in events:
  if fd in fdmap:
   c, addr = s.accept()
   print 'Got connection from', addr
   p.register(c)
   fdmap[c.fileno()]=c
  elif event & select.POLLIN:
   data = fdmap[fd].recv(1024)
   if not data:
    print fdmap[fd].getpeername(),'disconnected'
    p.unregister(fd)
    del fdmap[fd]
  else:
   print data

Twisted网络框架