DrupalResponse.php

<?php

namespace Drupal\Core\Response;

use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Routing\RequestContext;
use Symfony\Component\Routing\RouteCollection;
use Symfony\Component\Routing\Matcher\UrlMatcher;

class DrupalResponse {
  protected $context;
  protected $routes;

  public function __construct(RequestContext $context, RouteCollection $routes) {
    $this->context = $context;
    $this->routes = $routes;
  }

  public function getResponse(Request $request) {
    $matcher = new UrlMatcher($this->routes, $this->context);
    try {
      $attributes = $matcher->match($request->getPathInfo());
      $request->attributes->add($attributes);

      $menu_item = $attributes['menu item'];
      $this->arguments_populate($menu_item, $attributes, 'access arguments');
      if ($menu_item['access callback'] === TRUE || call_user_func_array($menu_item['access callback'], $menu_item['access arguments'])) {
        if (isset($menu_item['file'])) {
          require_once DRUPAL_ROOT . '/' . $menu_item['file path'] . '/'. $menu_item['file'];
        }
        $this->arguments_populate($menu_item, $attributes, 'page arguments');
        $output = call_user_func_array($menu_item['page callback'], $menu_item['page arguments']);
        if ($output) {
          $response = new Response(drupal_render_page($output));
        }
        else {
          $response = new Response(drupal_render_page('An error occurred'), 500);
        }
      }
      else {
        $response = new Response(drupal_render_page('Access Denied'), 403);
      }
    }
    catch (Exception $e) {
      $response = new Response(drupal_render_page('Not Found'), 404);
    }
    $response->prepare($request);
    return $response;
  }

  public function arguments_populate(&$menu_item, $attributes, $argument_type) {
    foreach ($menu_item[$argument_type] as &$argument) {
      if (is_numeric($argument)) {
        $load_callback = $attributes['arguments'][$argument] .'_load';
        if (function_exists($load_callback)) {
          $argument = $load_callback($attributes[$attributes['arguments'][$argument]]);
        }
      }
    }
  }
}