python如何创建TCP服务端和客户端

from socket import *
from time import ctime

HOST = ''
PORT = 9999
BUFSIZ = 1024
ADDR = (HOST, PORT)

tcpSerSock = socket(AF_INET, SOCK_STREAM)  #创建套接字
tcpSerSock.bind(ADDR)  #绑定IP和端口
tcpSerSock.listen(5)  #监听端口，最多5人排队

while True:
  print('waiting for connection...')
  tcpCliSock, addr = tcpSerSock.accept()  #建立连接
  print('...connected from:', addr)

  while True:
    data = tcpCliSock.recv(BUFSIZ)
    if not data:
      break
    content = '[%s] %s' % (bytes(ctime(), "utf-8"), data)
    print(data)
    print(type(content))
    tcpCliSock.send(content.encode("utf-8"))

  tcpCliSock.close()

tcpSerSock.close() 

from socket import *

HOST = '127.0.0.1' # or 'localhost'
PORT = 9999
BUFSIZ = 1024
ADDR = (HOST, PORT)

tcpCliSock = socket(AF_INET, SOCK_STREAM)
tcpCliSock.connect(ADDR)

while True:
  data = input('> ')
  if not data:
    break

  tcpCliSock.send(data.encode("utf-8"))
  data = tcpCliSock.recv(BUFSIZ)
  if not data:
    break
  print(data.decode("utf-8"))

tcpCliSock.close()