swoole_exmple/Server/udp.php

<?php
/**
 * UDP服务端类
 * User: fantasticbin
 * Date: 2020/1/15
 */
class Udp
{
    const HOST = '127.0.0.1';
    const PORT = 9502;
    const WORKER_NUM = 2;
    const MAX_REQUEST = 10000;

    public $server = null;

    public function __construct()
    {
        // 创建UDP服务器，第四个参数指定为UDP，监听 127.0.0.1:9502 端口
        $this->server = new Swoole\Server(self::HOST, self::PORT, SWOOLE_PROCESS, SWOOLE_SOCK_UDP);

        // 设置TCP服务器参数
        $this->server->set([
            'worker_num' => self::WORKER_NUM,
            'max_request' => self::MAX_REQUEST
        ]);

        // 监听数据接收事件
        $this->server->on('Packet', [$this, 'onPacket']);
    }

    /**
     * 监听数据接收事件
     * @param $serv Swoole\Server UDP对象
     * @param $data string 客户端传入的字符串
     * @param $clientInfo array 客户端信息数据
     */
    public function onPacket($serv, $data, $clientInfo)
    {
        $serv->sendto($clientInfo['address'], $clientInfo['port'], 'Hello ' . $data . '!' . PHP_EOL);
        var_dump($clientInfo);
    }

    /**
     * 启动UDP服务器
     */
    public function start()
    {
        $this->server->start();
    }
}

$udp = new Udp();
$udp->start();