Gateway::sendToClient PHP Method

    public static function sendToClient($client_id, $message)
    {
        return self::sendCmdAndMessageToClient($client_id, GatewayProtocol::CMD_SEND_TO_ONE, $message);
    }

<?php

require_once dirname(dirname(dirname(dirname(__DIR__)))) . '/Workerman/Autoloader.php';
require_once dirname(dirname(__DIR__)) . '/GatewayClient/Gateway.php';
\Workerman\Autoloader::setRootPath(__DIR__ . '/../../');
use GatewayWorker\Lib\Db;
use Workerman\Protocols\Http;
if (!isset($_POST['macid']) && !isset($_POST['buttonid'])) {
    echo "对不起，您访问的页面不存在！";
    HTTP::end();
}
$macid = $_POST['macid'];
$buttonid = $_POST['buttonid'];
$connectHC = Db::instance('ConnectHC');
$clientdata = $connectHC->row("SELECT clientid, sign FROM `WEBHC` WHERE macid='{$macid}'");
if (!Gateway::isOnline($clientdata['clientid'])) {
    echo "102";
    HTTP::end();
}
if (!$clientdata['sign']) {
    echo "103";
    HTTP::end();
}
Gateway::sendToClient($clientdata['clientid'], "{" . $buttonid . "}");
echo "101";
HTTP::end();
?>