Python实现的简单文件传输服务器和客户端

时间:2021-12-20 02:17:23

还是那个题目(题目和流程见java版本),感觉光用java写一点新意也没有,恰巧刚学习了python,何不拿来一用,呵呵:
服务器端:

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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:

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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() 

line-34到line-41处理文件下载,client收到server的“EOF”信号后,就知道文件传完了。
最后需要说明一下python的文件,由于是内置类型,所以不想java那样有那么多的reader,writer,input,ouput啊。python中,在打开或建立一个文件时,主要是通过模式(mode)来区别的。
python的网络编程确实简单,因为它提供了各种功能的已经写好的类,直接继承就Ok了。
python还在学习中,上面的例子跑通是没问题,但写得肯定不够好,还得学习啊