Python3 Socket

import socket

target_host = "www.sina.com"
target_port = 80

# 建立一个socket对象
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 连接客户端
client.connect((target_host, target_port))

# 发送一些数据
client.send(b'GET / HTTP/1.1\r\nHost: www.sina.com.cn\r\nConnection: close\r\n\r\n')

# 接收数据:
buffer = []
while True:
    # 每次最多接收1k字节:
    d = client.recv(1024)
    if d:
        buffer.append(d)
    else:
        break
data = b''.join(buffer)

# 关闭连接:
client.close()

header, html = data.split(b'\r\n\r\n', 1)
print(header.decode('utf-8'))
# 把接收的数据写入文件:
with open('sina.html', 'wb') as f:
    f.write(html)

import socket
import threading
import time

bind_ip = '0.0.0.0'
bind_port = 9999

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

server.bind((bind_ip, bind_port))

server.listen(5)

print("[*] Listening on %s: %d"%(bind_ip, bind_port))

def tcplink(sock, addr):
    print('Accept new connection from %s:%s...' % addr)
    sock.send(b'Welcome!')
    while True:
        data = sock.recv(1024)
        time.sleep(1)
        if not data or data.decode('utf-8') == 'exit':
            break
        sock.send(('Hello, %s!' % data.decode('utf-8')).encode('utf-8'))
    sock.close()
    print('Connection from %s:%s closed.' % addr)

while True:
    # 接受一个新连接:
    sock, addr = server.accept()
    # 创建新线程来处理TCP连接:
    t = threading.Thread(target=tcplink, args=(sock, addr))
    t.start()

import socket
s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 建立连接:
s.connect(('127.0.0.1', 9999))
# 接收欢迎消息:
print(s.recv(1024).decode('utf-8'))
for data in [b'Michael', b'Tracy', b'Sarah']:
    # 发送数据:
    s.send(data)
    print(s.recv(1024).decode('utf-8'))
s.send(b'exit')
s.close()