xyzshop/test/examples/namespace/server.php

<?php
use Swoole\Server;

$serv = new Server("127.0.0.1", 9501);

$serv->on('receive', function (Server $serv, $fd, $reactor_id, $data) {
    echo "[#".$serv->worker_id."]\tClient[$fd]: $data\n";
    if ($serv->send($fd, "hello\n") == false)
    {
        echo "error\n";
    }
});

$serv->start();