php__silex__book/src/demo/Errors/GenericErrorHandler.php

<?php

namespace demo\Errors;

use Silex\Application;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;

class GenericErrorHandler {

  /**
   * @var \Silex\Application
   */
  protected $app;

  public function __construct(Application $app) {
    $this->app = $app;
  }

  /* Custom error handlers registered with error() take precedence over the
    built-in error handler provider by Silex, but the formatted error messages it
    provides can be accessed in debug mode by returning based on $app['debug']
    like this.
   */
  public function __invoke(\Exception $e, Request $request, $code) {
  // Use the default handler in debug mode.
    if ($this->app['debug']) {
      return;
    }

    // Use our error formats otherwise.

    // 404.html, or 40x.html, or 4xx.html, or error.html
    $templates = [
      'errors/' . $code . '.html.twig',
      'errors/' . substr($code, 0, 2) . 'x.html.twig',
      'errors/' . substr($code, 0, 1) . 'xx.html.twig',
      'errors/default.html.twig',
    ];

    /** @var \Twig_Environment $twig */
    $twig = $this->app['twig'];
    /** @var \Twig_Template $template */
    $template = $twig->resolveTemplate($templates);
    return new Response($template->render(['code' => $code . ' : ' . $e->getMessage()]));
  }
}