Simple Hello World! HTTP server in PHP with Swoole

server.php

<?php
$http = new swoole_http_server("127.0.0.1", 9501);

$http->on("start", function ($server) {
    var_dump($server);
    echo "Swoole http server is started at http://127.0.0.1:9501\n";
});

$http->on("request", function ($request, $response) {
    var_dump($request);
    $response->header("Content-Type", "text/plain");
    $response->end("Hello World!\n");
});

$http->start();