[FIXED] Symfony 4 Custom Event Dispatcher not Working

Issue

I have followed the Symfony 4.3 docs to create a custom event, dispatch it, and listen for it. Tracing the execution of my controller, it looks like the event dispatcher does not find any subscribers, and I can't figure out what I'm doing wrong.

My event class is very basic:

namespace App\Event;

use Symfony\Contracts\EventDispatcher\Event;

class TestEvent extends Event
{
    public const NAME = 'test.event';

    protected $data;

    public function __construct(string $data)
    {
        $this->data = $data;
    }

    public function getData(): string
    {
        return $this->data;
    }
}

My controller instantiates and dispatches the event:

class TestController extends AbstractController
{
    private $eventDispatcher;

    public function __construct(EventDispatcherInterface $eventDispatcher, LoggerInterface $logger)
    {
        $this->eventDispatcher = $eventDispatcher;
    }

    /**
     * @Route("/event", name="event_test")
     */
    public function eventTest()
    {
        $event = new TestEvent('Event string');
        $this->eventDispatcher->dispatch($event);

        return $this->render('Test/TestEvent.html.twig', [
            'title' => 'Test Event',
            ]);
    }
}

I set up a subscriber to listen for the event and log. To make sure the subscriber works, I also subscribed to a Kernel event (that works):

namespace App\EventSubscriber;

use App\Event\TestEvent;
use Psr\Log\LoggerInterface;
use Symfony\Component\EventDispatcher\EventSubscriberInterface;
use Symfony\Component\HttpKernel\KernelEvents;

class TestSubscriber implements EventSubscriberInterface
{
    private $logger;

    public function __construct(LoggerInterface $logger)
    {
        $this->logger = $logger;
    }

    public static function getSubscribedEvents()
    {
        return [
            TestEvent::NAME => [['onTestEvent', 20]],
            KernelEvents::REQUEST => 'onKernelRequest',
        ];
    }

    public function onTestEvent(TestEvent $event)
    {
        $this->logger->info('Subscriber says: Found test event');
        $this->logger->info('Subscriber says: Test event posted this data {data}', [
            'data' => $event->getData(),
        ]);
    }

    public function onKernelRequest()
    {
        $this->logger->info('Got Kernel Request');
    }
}

When I visit the /event URL, I see the expected output, and the logs show the Kernel request, but they don't show the test.event log.

Per the docs, I ran

php bin/console debug:event-dispatcher test.event

at the console and got

Registered Listeners for "test.event" Event

---

Order Callable Priority

---

#1 App\EventSubscriber\TestSubscriber::onTestEvent() 20

---

That tells me the subscriber is registered, but for some reason it is not being called. Any help would be fantastic!

(BTW, I tried with an event listener as well, and got the same results.)

Thanks!

Solution

In symfony 4.3 if you dispatch event like this $this->eventDispatcher->dispatch($event); dispather use method get_class($event) as event name, so in your subscriber you need change

TestEvent::NAME => [['onTestEvent', 20]],

to

TestEvent::class=> [['onTestEvent', 20]],

For listener use this:

App\Event\TestListener:
        tags:
            - { 'name': 'kernel.event_listener', 'event': 'App\Event\TestEvent', 'method': 'onTestEvent' }

Answered By - Ihor Kostrov