import sys

 import socket

 import threading

 #回复消息，原样返回

 def replyMessage(conn):

     while True:

         data = conn.recv(1024)

         conn.send(data)

         if data.decode().lower() == 'bye':

             break

     conn.close()

 def main():

     sockScr = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     sockScr.bind(('', port))

     sockScr.listen(200)

     while True:

         try:

             conn, addr = sockScr.accept()

             #只允许特定主机访问本服务器

             if addr[0] != onlyYou:

                 conn.close()

                 continue

             #创建并启动线程

             t = threading.Thread(target=replyMessage, args=(conn,))

             t.start()

         except:

             print('error')

 if __name__ == '__main__':

     try:

         #获取命令行参数

         port = int(sys.argv[1])

         onlyYou = sys.argv[2]

         main()

     except:

         print('Must give me a number as port')
         

 import sys

 import socket

 import threading

 def middle(conn, addr):

     #面向服务器的Socket

     sockDst = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     sockDst.connect((ipServer,portServer))

     while True:

         data = conn.recv(1024).decode()

         print('收到客户端消息：'+data)

         if data == '不要发给服务器':

             conn.send('该消息已被代理服务器过滤'.encode())

             print('该消息已过滤')

         elif data.lower() == 'bye':

             print(str(addr)+'客户端关闭连接')

             break

         else:

             sockDst.send(data.encode())

             print('已转发服务器')

             data_fromServer = sockDst.recv(1024).decode()

             print('收到服务器回复的消息：'+data_fromServer)

             if data_fromServer == '不要发给客户端':

                 conn.send('该消息已被代理服务器修改'.encode())

                 print('消息已被篡改')

             else:

                 conn.send(b'Server reply:'+data_fromServer.encode())

                 print('已转发服务器消息给客户端')

     conn.close()

     sockDst.close()

 def main():

     sockScr = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     sockScr.bind(('', portScr))

     sockScr.listen(200)

     print('代理已启动')

     while True:

         try:

             conn, addr = sockScr.accept()

             t = threading.Thread(target=middle, args=(conn, addr))

             t.start()

             print('新客户：'+str(addr))

         except:

             pass

 if __name__ == '__main__':

     try:

         #(本机IP地址,portScr)<==>(ipServer,portServer)

         #代理服务器监听端口

         portScr = int(sys.argv[1])

         #服务器IP地址与端口号

         ipServer = sys.argv[2]

         portServer = int(sys.argv[3])

         main()

     except:

         print('Sth error')

 import sys

 import socket

 import threading

 def middle(conn, addr):

     #面向服务器的Socket

     sockDst = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     sockDst.connect((ipServer,portServer))

     while True:

         data = conn.recv(1024).decode()

         print('收到客户端消息：'+data)

         if data == '不要发给服务器':

             conn.send('该消息已被代理服务器过滤'.encode())

             print('该消息已过滤')

         elif data.lower() == 'bye':

             print(str(addr)+'客户端关闭连接')

             break

         else:

             sockDst.send(data.encode())

             print('已转发服务器')

             data_fromServer = sockDst.recv(1024).decode()

             print('收到服务器回复的消息：'+data_fromServer)

             if data_fromServer == '不要发给客户端':

                 conn.send('该消息已被代理服务器修改'.encode())

                 print('消息已被篡改')

             else:

                 conn.send(b'Server reply:'+data_fromServer.encode())

                 print('已转发服务器消息给客户端')

     conn.close()

     sockDst.close()

 def main():

     sockScr = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

     sockScr.bind(('', portScr))

     sockScr.listen(200)

     print('代理已启动')

     while True:

         try:

             conn, addr = sockScr.accept()

             t = threading.Thread(target=middle, args=(conn, addr))

             t.start()

             print('新客户：'+str(addr))

         except:

             pass

 if __name__ == '__main__':

     try:

         #(本机IP地址,portScr)<==>(ipServer,portServer)

         #代理服务器监听端口

         portScr = int(sys.argv[1])

         #服务器IP地址与端口号

         ipServer = sys.argv[2]

         portServer = int(sys.argv[3])

         main()

     except:

         print('Sth error')