创建三个继承类，PortForwarder用于监听本地，Receiver与PortForwarder套接字相连，用于接受本地请求，发给数据给远程主机，Sender与Receiver相互包含，用于接受远程主机数据和发送数据到本地。大致形成这样的关系：本地主机---PortForwarder---Receiver---Sender---远程主机
1 #!/usr/bin/env python 2 #-*- coding:utf-8 -*- 3 4 import argparse 5 import asyncore 6 import socket 7 8 LOCAL_SERVER_HOST = 'localhost' 9 REMOTE_SERVER_HOST = 'www.baidu.com' 10 BUFSIZE = 4096 11 LOCAL_SERVER_PORT = 0 12 13 class PortForwarder(asyncore.dispatcher):#监听本地 14 def __init__(self, ip, port, remoteip, remoteport, backlog=5): 15 asyncore.dispatcher.__init__(self) 16 self.remoteip = remoteip 17 self.remoteport = remoteport 18 self.create_socket(socket.AF_INET, socket.SOCK_STREAM)#创建一个套接字对象 19 self.set_reuse_addr()#设置地址端口可重用 20 self.bind((ip, port))#绑定本地ip与端口 21 self.listen(backlog)#开始监听 22 23 def handle_accept(self):#处理接受 24 conn, addr = self.accept()#等待接受 25 print "Connected to:", addr 26 Sender(Receiver(conn), self.remoteip, self.remoteport) 27 28 class Receiver(asyncore.dispatcher):#接受本地请求数据，发送给远程主机 29 def __init__(self, conn): 30 asyncore.dispatcher.__init__(self, conn) 31 #self被初始化为该连接客户端socket 32 #getpeername函数用于获取与某个套接字关联的外地协议地址 33 self.from_remote_buffer = ''#保存来自远程主机数据 34 self.to_remote_buffer = '' #保存本地请求数据 35 self.sender = None 36 37 def handle_connect(self): 38 pass 39 40 def handle_read(self):#接受本地请求 41 read = self.recv(BUFSIZE) 42 self.to_remote_buffer += read; 43 print "receiver read", self.to_remote_buffer 44 45 def writable(self):#判断是否有来自远程主机的数据，如果有，调用handle_write 46 return (len(self.from_remote_buffer) > 0) 47 48 def handle_write(self):#发送来自远程主机的数据给本地主机 49 sent = self.send(self.from_remote_buffer) 50 print "receiver sent", sent 51 self.from_remote_buffer = self.from_remote_buffer[sent:]#发送完成后清空数据 52 53 def handle_close(self): 54 self.close() 55 if self.sender: 56 self.sender.close() 57 58 class Sender(asyncore.dispatcher):#接受远程主机数据，发送本地请求数据 59 def __init__(self, receiver, remoteaddr, remoteport): 60 asyncore.dispatcher.__init__(self) 61 self.receiver = receiver#建立Sender与Receiver之间联系 62 receiver.sender = self #建立Sender与Receiver之间联系 63 self.create_socket(socket.AF_INET, socket.SOCK_STREAM)#创建套接字 64 self.connect((remoteaddr, remoteport))#连接远程主机 65 66 def handle_connect(self): 67 pass 68 69 def handle_read(self):#接受来自远程主机的数据 70 read = self.recv(BUFSIZE) 71 self.receiver.from_remote_buffer += read 72 print "sender read", self.receiver.from_remote_buffer 73 74 def writable(self):#判断是否有本地请求要发送，如果有，调用handle_write 75 if len(self.receiver.to_remote_buffer) > 0: 76 self.receiver.to_remote_buffer = self.receiver.to_remote_buffer.replace 77 (LOCAL_SERVER_HOST + ':' + str(LOCAL_SERVER_PORT), REMOTE_SERVER_HOST) 78 #修改本地请求数据，将本地主机中host改为远程主机地址 79 return (len(self.receiver.to_remote_buffer) > 0) 80 81 def handle_write(self):#发送本地请求数据 82 sent = self.send(self.receiver.to_remote_buffer) 83 print "sender write",sent 84 self.receiver.to_remote_buffer = self.receiver.to_remote_buffer[sent:] 85 86 def handle_close(self): 87 self.close() 88 self.receiver.close() 89 90 if __name__ == '__main__': 91 parser = argparse.ArgumentParser(description="stackless socket server example") 92 parser.add_argument('--localhost', action="store", dest="local_host", default=LOCAL_SERVER_HOST) 93 parser.add_argument('--local-port', action="store", dest="local_port", type=int, required=True) 94 parser.add_argument('--romote-port', action="store", dest="remote_host",default=REMOTE_SERVER_HOST) 95 parser.add_argument('--remot-port', action="store", dest="remote_port", type=int, default=80) 96 given_args = parser.parse_args() 97 local_host, remote_host = given_args.local_host, given_args.remote_host 98 local_port, remote_port = given_args.local_port, given_args.remote_port 99 LOCAL_SERVER_PORT = local_port 100 print "start port forwarding local %s:%s => remote %s:%s" % 101 (local_host, local_port, remote_host, remote_port) 102 PortForwarder(local_host, local_port, remote_host, remote_port) 103 asyncore.loop()