.router.php

<?php

if (php_sapi_name() !== 'cli-server') {
    die("This is the router for PHP's built-in development webserver. See https://www.php.net/manual/en/features.commandline.webserver.php for more details.");
}

// Don't interpret public files.
if (is_file($_SERVER['DOCUMENT_ROOT'] . '/' . $_SERVER['SCRIPT_NAME'])) {
    return false;
}

$_SERVER['SCRIPT_NAME'] = '/index.php';

require __DIR__ . '/index.php';