python socket连接放在循环内为什么只有第一次执行了?

Question

我写了一个demo测试一下python的socket用法.
客户端有个循环, 我的socket连接和close写在循环体外面没有问题, 但写在循环内服务器却提示只收到了第一次的请求
代码如下:

server.py

#!/usr/bin/env python3

import socket
import time

HOST = '127.0.0.1'  # 标准的回环地址 (localhost)
PORT = 65432        # 监听的端口 (非系统级的端口: 大于 1023)

with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s:
    print(111)
    s.bind((HOST, PORT))
    s.listen()
    conn, addr = s.accept()
    with conn:
        print('Connected by', addr)
        while True:
            data = conn.recv(1024)
            if data:
                print('receive: ', data)
                conn.sendall(b'1')
                time.sleep(1)
                conn.sendall(b'2')
                time.sleep(1)
                conn.sendall(b'3')

client.py

#!/usr/bin/env python3

import socket

# SOCKET连接在循环体外
# sendData = [
#     'aaaaaaaaaaaaaaaaa',
#     'bbbbbbbbbbbbbbbbbbbbbbbbb',
#     'ccccccccccccccccccccccc'
# ]
# HOST = '127.0.0.1'  # 服务器的主机名或者 IP 地址
# PORT = 65432        # 服务器使用的端口


# sk = socket.socket()
# sk.connect((HOST, PORT))
# print('conn success')

# for d in sendData:

#     print('current:', d)

#     sk.sendall(bytes(d, encoding='utf-8'))
#     print('sent')
#     while True:
#         server_reponse = sk.recv(2048)
#         if (server_reponse):
#             recData = str(server_reponse, encoding='utf-8')
#             print('Received', recData)
#             if recData == '3':
#                 print('===================')
#                 break

# sk.close()
# print('conn closed')


# SOCKET连接在循环体内
sendData = [
    'aaaaaaaaaaaaaaaaa',
    'bbbbbbbbbbbbbbbbbbbbbbbbb',
    'ccccccccccccccccccccccc'
]
HOST = '127.0.0.1'  # 服务器的主机名或者 IP 地址
PORT = 65432        # 服务器使用的端口



for d in sendData:
    sk = socket.socket()
    sk.connect((HOST, PORT))
    print('conn success')

    print('current:', d)

    sk.sendall(bytes(d, encoding='utf-8'))
    print('sent')
    while True:
        server_reponse = sk.recv(2048)
        if (server_reponse):
            recData = str(server_reponse, encoding='utf-8')
            print('Received', recData)
            if recData == '3':
                sk.close()
                print('conn closed')
                print('===================')
                break