Python socket库实现原生TCP请求

import socket

# 创建TCP套接字 SOCK_STREAM = TCP
client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

# 目标服务端地址
host = "127.0.0.1"
port = 9000

try:
    # 发起三次握手，建立TCP连接
    client.connect((host, port))
    # 发送二进制数据
    client.send("Hello TCP Server".encode("utf-8"))
    # 阻塞等待接收服务端返回数据，缓冲区1024字节
    recv_data = client.recv(1024)
    print("收到服务端返回：", recv_data.decode("utf-8"))
except ConnectionRefusedError:
    print("端口未开放，TCP连接失败")
finally:
    # 关闭连接，释放资源
    client.close()

import socket

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# 绑定0.0.0.0，允许局域网所有设备访问
server.bind(("0.0.0.0", 9000))
# 开启监听，最大挂起队列5
server.listen(5)
print("TCP服务端已启动，监听9000端口")

while True:
    # 阻塞等待客户端连接
    conn, addr = server.accept()
    print(f"新客户端接入：{addr}")
    # 接收客户端消息
    data = conn.recv(1024)
    print("收到消息：", data.decode())
    # 回复数据
    conn.send("消息已收到".encode("utf-8"))
    # 关闭本次客户端连接（短连接模式）
    conn.close()

import socket

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(("127.0.0.1", 9000))

# 循环发送多条数据，连接不断开
for i in range(3):
    msg = f"第{i+1}条消息".encode("utf-8")
    client.send(msg)
    res = client.recv(1024)
    print("接收:", res.decode())

client.close()

import socket

server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.bind(("0.0.0.0", 9000))
server.listen(5)

while True:
    conn, addr = server.accept()
    print("客户端已连接")
    # 持续读取客户端消息
    while True:
        data = conn.recv(1024)
        if not data:
            # 客户端关闭连接，recv会拿到空字节
            break
        print(data.decode())
        conn.send("ok".encode())
    conn.close()

import socket

def check_tcp_port(host, port, timeout=2):
    sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sock.settimeout(timeout)
    try:
        sock.connect((host, port))
        return True, "端口开放"
    except Exception:
        return False, "端口关闭或无法连接"
    finally:
        sock.close()

# 测试
print(check_tcp_port("www.baidu.com", 80))
print(check_tcp_port("127.0.0.1", 9999))

import socket

client = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
client.connect(("www.baidu.com", 80))

# 原始HTTP GET报文
http_msg = b"GET / HTTP/1.1\r\nHost: www.baidu.com\r\nConnection: close\r\n\r\n"
client.send(http_msg)

# 接收网页响应
response = client.recv(4096)
print(response.decode("utf-8", errors="ignore"))
client.close()

server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)