iot-admin/app/mqtt/Subscribe.php

<?php

namespace app\mqtt;

class Subscribe
{

    public static function onWorkerStart()
    {
        $mqtt = new \Workerman\Mqtt\Client('mqtt://ceshi-mqtt.lihaink.cn/tcp', array(
            // 'debug' => true,
            "username"=>"demo2",
            "password"=>"123456",
            "client_id"=>"mqttx_4fde83eb"
        ));
        $mqtt->onConnect = function($mqtt) {
            $mqtt->subscribe('demo');
        };
        $mqtt->onMessage = function($topic, $content) {
            echo "topic:$topic content:$content\n";
        };
        $mqtt->connect();
    }


}