Example PHP CGI-style front controller

index.php

<?php

// Static list provides security against URL injection by default.
switch (@parse_url($_SERVER['REQUEST_URI'])['path']) {
    case '/': 
        require 'homepage.php';
        break;
    case 'admin.php': 
        require 'admin.php';
        break;
    default:
        http_response_code(404);
        exit('Not Found');
}