Python UDP编程详解 - 广播与多播实战教程

import socket

# 创建UDP Socket
udp_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# 绑定地址（服务端）
udp_socket.bind(('localhost', 9999))

# 发送数据（客户端）
udp_socket.sendto(b'Hello UDP!', ('localhost', 9999))

# 接收数据
data, addr = udp_socket.recvfrom(1024)
print(f'收到来自 {addr}: {data.decode()}')

import socket

# 创建UDP Socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)

# 发送数据 - sendto需要指定目标地址
message = "Hello, UDP Server!"
sock.sendto(message.encode('utf-8'), ('localhost', 8888))

# 接收响应 - recvfrom返回 (数据, 发送者地址)
response, server_addr = sock.recvfrom(1024)
print(f'服务器响应: {response.decode("utf-8")}')

sock.close()

import socket

# 创建广播Socket
broadcast_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
# 启用广播选项
broadcast_sock.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)

# 向广播地址发送数据
message = "Broadcast message!"
broadcast_sock.sendto(message.encode('utf-8'), ('<broadcast>', 5000))
print(f'已发送广播消息: {message}')

broadcast_sock.close()

# 接收广播 - 服务端
def broadcast_receiver(port=5000):
    """接收广播消息"""
    recv_sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    # 允许端口重用
    recv_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    # 绑定到所有接口的指定端口
    recv_sock.bind(('', port))
    
    print(f'监听广播端口 {port}...')
    while True:
        data, addr = recv_sock.recvfrom(1024)
        print(f'收到来自 {addr} 的广播: {data.decode("utf-8")}')

# 在另一个终端运行 broadcast_receiver() 来接收广播

import socket
import struct

# 多播发送
def multicast_sender(message, group='224.1.1.1', port=5000):
    """发送多播消息"""
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    # 设置TTL（生存时间），控制多播传播范围
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
    sock.sendto(message.encode('utf-8'), (group, port))
    print(f'已发送多播消息到 {group}:{port}')
    sock.close()

# 多播接收
def multicast_receiver(group='224.1.1.1', port=5000):
    """接收多播消息"""
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    # 允许端口重用
    sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    # 绑定到多播端口
    sock.bind(('', port))
    
    # 加入多播组
    mreq = struct.pack('4sl', socket.inet_aton(group), socket.INADDR_ANY)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
    
    print(f'已加入多播组 {group}，等待消息...')
    while True:
        data, addr = sock.recvfrom(1024)
        print(f'收到多播消息: {data.decode("utf-8")}')

# udp_chat_server.py - UDP聊天服务端
import socket
import threading

def udp_chat_server(host='localhost', port=9000):
    """UDP聊天服务端"""
    server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    server.bind((host, port))
    print(f'UDP聊天服务端已启动，监听 {host}:{port}')
    
    clients = {}  # 存储客户端信息
    
    while True:
        data, addr = server.recvfrom(1024)
        message = data.decode('utf-8')
        
        if addr not in clients:
            clients[addr] = f'用户{len(clients)+1}'
            print(f'{clients[addr]} 加入聊天')
        
        # 转发消息给所有客户端
        broadcast_msg = f'{clients[addr]}: {message}'
        print(broadcast_msg)
        for client_addr in clients:
            server.sendto(broadcast_msg.encode('utf-8'), client_addr)

if __name__ == '__main__':
    udp_chat_server()

# udp_chat_client.py - UDP聊天客户端
import socket
import threading

def udp_chat_client(server_host='localhost', server_port=9000):
    """UDP聊天客户端"""
    client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    
    # 启动接收线程
    def receive_messages():
        while True:
            try:
                data, _ = client.recvfrom(1024)
                print(f'\n{data.decode("utf-8")}')
                print('输入消息 > ', end='', flush=True)
            except:
                break
    
    recv_thread = threading.Thread(target=receive_messages, daemon=True)
    recv_thread.start()
    
    # 发送消息
    print('已连接到聊天服务器')
    while True:
        message = input('输入消息 > ')
        if message.lower() == 'quit':
            break
        client.sendto(message.encode('utf-8'), (server_host, server_port))
    
    client.close()
    print('已退出聊天')

if __name__ == '__main__':
    udp_chat_client()

# udp_time_server.py - UDP时间服务器
import socket
import time
from datetime import datetime

def time_server(host='localhost', port=12345):
    """UDP时间服务器"""
    server = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    server.bind((host, port))
    print(f'时间服务器已启动，监听 {host}:{port}')
    
    while True:
        data, addr = server.recvfrom(1024)
        request = data.decode('utf-8')
        current_time = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
        response = f'当前时间: {current_time}'
        server.sendto(response.encode('utf-8'), addr)
        print(f'响应 {addr}: {response}')

# udp_time_client.py - UDP时间客户端
def time_client(host='localhost', port=12345):
    """查询服务器时间"""
    client = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    client.settimeout(5)  # 设置超时
    
    try:
        client.sendto(b'GET TIME', (host, port))
        response, _ = client.recvfrom(1024)
        print(response.decode('utf-8'))
    except socket.timeout:
        print('请求超时，服务器无响应')
    finally:
        client.close()