src/Form/EventListener/ReCaptchaValidationListener.php line 59

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  1. <?php
  3. namespace App\Form\EventListener;
  5. use ReCaptcha\ReCaptcha;
  6. use Symfony\Component\EventDispatcher\EventSubscriberInterface;
  7. use Symfony\Component\Form\FormError;
  8. use Symfony\Component\Form\FormEvent;
  9. use Symfony\Component\Form\FormEvents;
  10. use Symfony\Component\HttpFoundation\Request;
  11. use Symfony\Contracts\Translation\TranslatorInterface;
  13. /**
  14.  * This event subscriber validates the catpcha's response using the google Recaptcha PHP
  15.  * library.
  16.  *
  17.  * @see https://medium.com/@qferrer/securing-your-symfony-forms-with-google-recaptcha-v2-dbfc902b0c50
  18.  *
  19.  * @author jra
  20.  *
  21.  */
  22. class ReCaptchaValidationListener implements EventSubscriberInterface
  23. {
  24.     /**
  25.      * @var \ReCaptcha\ReCaptcha
  26.      */
  27.     private $reCaptcha;
  29.     /**
  30.      * @var \Symfony\Contracts\Translation\TranslatorInterface
  31.      */
  32.     protected $translator;
  34.     /**
  35.      * @var string
  36.      */
  37.     private $invalidMessage = 'error.form.captcha_invalid';
  39.     public function __construct(ReCaptcha $reCaptcha, TranslatorInterface $translator)
  40.     {
  41.         $this->reCaptcha = $reCaptcha;
  42.         $this->translator = $translator;
  43.     }
  45.     public static function getSubscribedEvents()
  46.     {
  47.         return [
  48.             FormEvents::POST_SUBMIT => 'onPostSubmit'
  49.         ];
  50.     }
  52.     public function setInvalidMessage($message)
  53.     {
  54.         $this->invalidMessage = $message;
  56.         return $this;
  57.     }
  59.     public function onPostSubmit(FormEvent $event)
  60.     {
  61.         $request = Request::createFromGlobals();
  63.         // This will trust all proxies
  64.         // @see : https://symfony.com/doc/current/deployment/proxies.html
  65.         $request->setTrustedProxies(['127.0.0.1', 'REMOTE_ADDR'], Request::HEADER_X_FORWARDED_ALL);
  67.         // Note that DNS resolution on the PHP server must work properly, otherwise reCaptcha will return a 'connection-refused' error
  68.         $result = $this->reCaptcha
  69.             ->setExpectedHostname($request->getHost())
  70.             ->verify($request->request->get('g-recaptcha-response'), $request->getClientIp());
  72.         if (!$result->isSuccess()) {
  73.           $errors = $result->getErrorCodes();
  74.           $msg = $this->translator->trans($this->invalidMessage, ['message' => implode(', ', $errors)]);
  75.           $event->getForm()->addError(new FormError($msg));
  76.         }
  77.     }
  78. }