python3 implements simple server and client of TCP protocol

from socket import *host  = '192.168.48.128'port  = 13141addr = (host,port)
bufsize=1024tcpClient = socket(AF_INET,SOCK_STREAM) # 这里的参数和UDP不一样。tcpClient.connect(addr) #由于tcp三次握手机制，需要先连接while True:
    data  = input('>>> ').encode(encoding="utf-8")if not data:break# 数据收发和UDP基本一致tcpClient.send(data) 
    data = tcpClient.recv(bufsize).decode(encoding="utf-8") print(data)

tcpClient.close()

from socket import *from time import ctimeimport os 

host = ''port = 13140bufsize = 1024addr = (host,port)

tcpServer = socket(AF_INET,SOCK_STREAM)
tcpServer.bind(addr)
tcpServer.listen(5) #这里设置监听数为5(默认值),有点类似多线程。while True:print('Waiting for connection...')
    tcpClient,addr = tcpServer.accept() #拿到5个中一个监听的tcp对象和地址print('[+]...connected from:',addr)while True:
        cmd = tcpClient.recv(bufsize).decode(encoding="utf-8") print('   [-]cmd:',cmd)if not cmd:break###这里在cmd中执行来自客户端的命令，并且将结果返回###cmd = os.popen(cmd) ###os.popen(cmd)对象是file对象子类，所以可以file的方法cmdResult = cmd.read()
        cmdStatus = cmd.close()#################################################data = cmdResult if (not cmdStatus) else "ERROR COMMAND"tcpClient.send(data.encode(encoding="utf-8"))

    tcpClient.close() #print(addr,'End')
tcpServer.close() #两次关闭，第一次是tcp对象，第二次是tcp服务器