Event Subscribers in Silex

app.php

$app->extend('dispatcher', function ($dispatcher) use ($app) {
	$dispatcher->addSubscriber(new \APP\EventSubscriber\ContributionSubscriber($app['orm.em']));
	return $dispatcher;
});

Call dispatch

public function createNewContributionAction(Request $request, int $userReviewId, int $review_id)
{
	$user = $this->getApp()['user'];
	$userReview = $this->getRepository(UserReview::class)->findBy(['id' => $userReviewId]);
	$userReview = $userReview[0];
	$form = $this->getFormFactory()->createBuilder(CreateContributionType::class)->getForm();
	$form->handleRequest($request);
	if ($form->isSubmitted()) {
		if (isset($_POST['save'])) {
			$data = $form->getData();
			$data->setUserReview($userReview);
			$this->getEntityManager()->persist($data);
			$this->getEntityManager()->flush();

			$dispatcher = $this->getApp()['dispatcher'];
			$dispatcher->dispatch(ContributionEvent::CONTRIBUTION_ADDED, new ContributionEvent($data, $user));
			return $this->backToUserReview($review_id);
		}
	}
	return $this->render('create_new_review.html.twig', ['form' => $form->createView()]);
}

ContributionEvent

class ContributionEvent extends Event
{
    const CONTRIBUTION_ADDED   = 'contribution_added';
    const CONTRIBUTION_UPDATED = 'contribution_updated';
    const CONTRIBUTION_DELETED = 'contribution_deleted';


    private $contribution;
    private $user;
    public function __construct(Contribution $contribution, User $user)
    {
        $this->contribution = $contribution;
        $this->user = $user;
    }

    /**
     * @return Contribution
     */
    public function getContribution(): Contribution
    {
        return $this->contribution;
    }

    /**
     * @return User
     */
    public function getUser(): User
    {
        return $this->user;
    }
}

ContributionSubscriber

class ContributionSubscriber implements EventSubscriberInterface
{
	/**
	 * Default action for logs
	 */
	const UNKNOWN_ACTION = 'unknown_action';

	/**
	 * @var EntityManager
	 */
	protected $entityManager;

	/**
	 * AbstractSubscriber constructor.
	 * @param EntityManager $entityManager
	 */
	public function __construct(EntityManager $entityManager)
	{
		$this->entityManager = $entityManager;
	}

	/**
	 * @param RecentActivity $recentActivity
	 */
	protected function logEntity(RecentActivity $recentActivity)
	{
		$this->entityManager->merge($recentActivity);
		$this->entityManager->flush();
	}
	
	/**
	 * @return array
	 */
	public static function getSubscribedEvents()
	{
		return [
			ContributionEvent::CONTRIBUTION_ADDED    => 'onContributionAdded',
			ContributionEvent::CONTRIBUTION_UPDATED  => 'onContributionUpdated',
			ContributionEvent::CONTRIBUTION_DELETED  => 'onContributionDeleted'
		];
	}

	/**
	 * @param ContributionEvent $event
	 */
	public function onContributionAdded(ContributionEvent $event)
	{
		$entity = new RecentActivity();
		$entity->setUser($event->getUser());
		$entity->setContribution($event->getContribution());

		$this->logEntity($entity);
	}

	/**
	 * @param ContributionEvent $event
	 */
	public function onContributionUpdated(ContributionEvent $event)
	{
		$this->logEntity(ContributionEvent::CONTRIBUTION_UPDATED, [
			'contribution' => $event->getEntity()->getContribution()
		]);
	}

	/**
	 * @param ContributionEvent $event
	 */
	public function onContributionDeleted(ContributionEvent $event)
	{
		$this->logEntity(ContributionEvent::CONTRIBUTION_DELETED, [
			'contribution' => $event->getEntity()->getContribution()
		]);
	}
}