Python实现的简单文件传输服务器和客户端

import SocketServer, time 
 
class MyServer(SocketServer.BaseRequestHandler):  
  userInfo = {  
    'yangsq'  : 'yangsq',  
    'hudeyong' : 'hudeyong',  
    'mudan'   : 'mudan' }  
 
  def handle(self):  
    print 'Connected from', self.client_address  
      
    while True:  
      receivedData = self.request.recv(8192)  
      if not receivedData:  
        continue 
        
      elif receivedData == 'Hi, server':  
        self.request.sendall('hi, client')  
          
      elif receivedData.startswith('name'):  
        self.clientName = receivedData.split(':')[-1]  
        if MyServer.userInfo.has_key(self.clientName):  
          self.request.sendall('valid')  
        else:  
          self.request.sendall('invalid')  
            
      elif receivedData.startswith('pwd'):  
        self.clientPwd = receivedData.split(':')[-1]  
        if self.clientPwd == MyServer.userInfo[self.clientName]:  
          self.request.sendall('valid')  
          time.sleep(5)  
 
          sfile = open('PyNet.pdf', 'rb')  
          while True:  
            data = sfile.read(1024)  
            if not data:  
              break 
            while len(data) > 0:  
              intSent = self.request.send(data)  
              data = data[intSent:]  
 
          time.sleep(3)  
          self.request.sendall('EOF')  
        else:  
          self.request.sendall('invalid')  
            
      elif receivedData == 'bye':  
        break 
 
    self.request.close()  
      
    print 'Disconnected from', self.client_address  
    print 
 
if __name__ == '__main__':  
  print 'Server is started\nwaiting for connection...\n'  
  srv = SocketServer.ThreadingTCPServer(('localhost', 50000), MyServer)  
  srv.serve_forever()       

说明：
line-55到line-58的作用就相当于java中某个类里面的main函数，即一个类的入口。
python中SocketServer module里提供了好多实用的现成的类，BaseRequestHandler就是一个，它的作用是为每一个请求fork一个线程，只要继承它，就有这个能力了，哈哈，真是美事。
当然，我们继承了BaseRequestHandler，就是override它的handle方法，就像java中继承了Thread后要实现run方法一样。实际上这个handle方法的内容和我们的java版本的run函数实现的完全一样。
line-30到line-43就是处理文件下载的主要内容了。看着都挺眼熟的呵：）
这里在文件发送完后发了一个“EOF”，告诉client文件传完了。
客户端：

import socket, time 
 
class MyClient:  
 
  def __init__(self):  
    print 'Prepare for connecting...'  
 
  def connect(self):  
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  
    sock.connect(('localhost', 50000))  
 
    sock.sendall('Hi, server')  
    self.response = sock.recv(8192)  
    print 'Server:', self.response  
 
    self.s = raw_input("Server: Do you want get the 'thinking in python' file?(y/n):")  
    if self.s == 'y':  
      while True:  
        self.name = raw_input('Server: input our name:')  
        sock.sendall('name:' + self.name.strip())  
        self.response = sock.recv(8192)  
        if self.response == 'valid':  
          break 
        else:  
          print 'Server: Invalid username'  
 
      while True:  
        self.pwd = raw_input('Server: input our password:')  
        sock.sendall('pwd:' + self.pwd.strip())  
        self.response = sock.recv(8192)  
        if self.response == 'valid':  
          print 'please wait...'  
 
          f = open('b.pdf', 'wb')  
          while True:  
            data = sock.recv(1024)  
            if data == 'EOF':  
              break 
            f.write(data)  
              
          f.flush()  
          f.close()  
 
          print 'download finished'  
          break 
        else:  
          print 'Server: Invalid password'  
          
 
    sock.sendall('bye')  
    sock.close()  
    print 'Disconnected'  
 
if __name__ == '__main__':  
  client = MyClient()  
  client.connect()