php error_reporting E_ALL E_NOTICE define __XUJ__ true require_once Co

<?php
error_reporting(E_ALL | E_NOTICE);
define('__XUJ__', true);
require_once 'Core/Core.class.php';
$real_server_name = str_replace('www.', '', $_SERVER['HTTP_HOST']);
if($real_server_name != $_SERVER['HTTP_HOST']) {
    header('Location: http://'.$real_server_name);
    exit;
}
$section = explode('/', preg_replace('/\/?\?(.*?)$/', '', substr(preg_replace('/\/+/', '/', $_SERVER['REQUEST_URI']), 1)));
switch($section[0]) {
    case '404':
        echo 'Ошибка 404';
        break;
    case '403':
        echo 'Ошибка 403';
        break;
    default:
        if(empty($section[0])) {
            echo 'Home Page!';
        }
        else {
            header('Location: /404/');
            exit;
        }
        break;
}