Python 50行代码实现代理服务器（加强版）

网上很多python 50行代码实现代理服务器，但是易出现异常，导致退出。

这里的代理服务器，是指二级代理服务器。比如：A可以访问B，B可以访问C，A不能直接访问C。这时，如果在B开一个二级代理，就可实现A访问C。现有的工具有CCProxy。

这里就是使用Python简单的实现一个二级代理。

#coding=utf-8
import socket
import select
import sys
import threading
import time
import logging
import os
logsDir = "logs"
if not os.path.isdir(logsDir):
    os.mkdir(logsDir)

logging.basicConfig(level=logging.DEBUG,
                format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s',
                datefmt='%a, %d %b %Y %H:%M:%S',
                filename='logs/logs.log',
                filemode='a')

#C的IP和端口
to_addr = ('0.0.0.0', 8087)

class Proxy:
    def __init__(self, addr):
        self.proxy = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        self.proxy.bind(addr)
        self.proxy.listen(10)
        self.inputs = [self.proxy]
        self.route = {} 

    def serve_forever(self):
        logging.info('proxy listen...')
        while 1:
            readable, _, _ = select.select(self.inputs, [], [])
            for self.sock in readable:
                if self.sock == self.proxy:
                    self.on_join()
                else:
                    try:
                        data = self.sock.recv(8192)
                    except Exception, e:
                        logging.error(str(e))
                        self.on_quit()
                        continue

                    if not data:
                        self.on_quit()
                    else:
                        try:
                            self.route[self.sock].send(data)
                        except Exception, e:
                            logging.error(str(e))
                            self.on_quit()
                            continue

    def on_join(self):
        client, addr = self.proxy.accept()
        logging.info("proxy client " + str(addr) + 'connect')
        forward = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        forward.connect(to_addr)
        self.inputs += [client, forward]
        self.route[client] = forward
        self.route[forward] = client 

    #删除连接
    def on_quit(self):
        ls = [self.sock]
        if self.sock in self.route:
            ls.append(self.route[self.sock])
        for s in ls:
            if s in self.inputs:
                self.inputs.remove(s)
            if s in self.route:
                del self.route[s]
            s.close() 

if __name__ == "__main__":
    try:
        Proxy(('', 8192)).serve_forever()
    except KeyboardInterrupt:
        logging.error("KeyboardInterrupt")
        return