How to create a new event in Symfony?

by arnoldo.moen , in category: PHP Frameworks , a year ago

How to create a new event in Symfony?

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2 answers

Member

by dedrick , a year ago

@arnoldo.moen 

To create a new event in Symfony, you can follow these steps:

  1. Define the event class: Create a new class that extends the SymfonyComponentEventDispatcherEvent class. This class will define the event and its properties. For example:
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namespace AppEvent;

use SymfonyComponentEventDispatcherEvent;

class NewEvent extends Event
{
    const NAME = 'new.event';

    private $data;

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

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


  1. Register the event: To register the event, you can use the SymfonyComponentEventDispatcherEventDispatcherInterface class. In your service configuration file (e.g. services.yaml), add a new service with the tag "event_dispatcher.event_subscriber" and pass the EventDispatcherInterface object as an argument.
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services:
    AppEventListenerMyListener:
        tags:
            - { name: kernel.event_listener, event: 'new.event', method: onNewEvent }


  1. Trigger the event: To trigger the event, you can use the SymfonyComponentEventDispatcherEventDispatcherInterface class. Create a new instance of your event class and pass it to the dispatch method of the EventDispatcherInterface object.
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$event = new NewEvent($data);
$dispatcher->dispatch(NewEvent::NAME, $event);


  1. Create event listeners: Create one or more event listeners to handle the event. An event listener is a PHP class that contains a method that is executed when the event is triggered.
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namespace AppEventListener;

use AppEventNewEvent;

class MyListener
{
    public function onNewEvent(NewEvent $event)
    {
        // Do something with the event data
        $data = $event->getData();
    }
}


By following these steps, you can create a new event in Symfony and handle it using event listeners.

Member

by larissa , 10 months ago

@arnoldo.moen 

To create a new event in Symfony, you can follow these steps:

  1. Define the event class: Create a new PHP class that represents your event. This class should extend the SymfonyContractsEventDispatcherEvent class or implement the SymfonyContractsEventDispatcherEventInterface interface. In this class, you can define any properties or methods that are necessary to represent your event.


For example, let's say you want to create an event that is triggered when a user logs in. You could create a UserLoggedInEvent class like this:

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namespace AppEvent;

use SymfonyContractsEventDispatcherEvent;

class UserLoggedInEvent extends Event
{
    private $user;

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

    public function getUser()
    {
        return $this->user;
    }
}


  1. Dispatch the event: Once you have defined your event class, you can dispatch it from any part of your code where the event occurs. You can do this using the SymfonyContractsEventDispatcherEventDispatcherInterface service.


For example, let's say you want to dispatch the UserLoggedInEvent event when a user logs in. You could do this in your login controller like this:

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namespace AppController;

use AppEventUserLoggedInEvent;
use SymfonyBundleFrameworkBundleControllerAbstractController;
use SymfonyComponentHttpFoundationRequest;
use SymfonyComponentRoutingAnnotationRoute;
use SymfonyContractsEventDispatcherEventDispatcherInterface;

class LoginController extends AbstractController
{
    /**
     * @Route("/login", name="login")
     */
    public function login(Request $request, EventDispatcherInterface $eventDispatcher)
    {
        // Handle login logic...

        // Dispatch the UserLoggedInEvent event
        $user = ...; // get the logged-in user
        $event = new UserLoggedInEvent($user);
        $eventDispatcher->dispatch($event);

        // Redirect to the homepage
        return $this->redirectToRoute('homepage');
    }
}


  1. Subscribe to the event: Finally, you can create one or more event subscribers to listen for your new event and perform any necessary actions when it occurs. To do this, you can create a new PHP class that implements the SymfonyContractsEventDispatcherEventSubscriberInterface interface.


For example, let's say you want to send an email notification when a user logs in. You could create a UserLoggedInSubscriber class like this:

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namespace AppEventSubscriber;

use AppEventUserLoggedInEvent;
use SymfonyComponentEventDispatcherEventSubscriberInterface;

class UserLoggedInSubscriber implements EventSubscriberInterface
{
    public static function getSubscribedEvents()
    {
        return [
            UserLoggedInEvent::class => 'onUserLoggedIn',
        ];
    }

    public function onUserLoggedIn(UserLoggedInEvent $event)
    {
        // Send email notification to the user
        $user = $event->getUser();
        $message = ...; // create email message
        $mailer = ...; // get mailer service
        $mailer->send($message);
    }
}


To register this event subscriber, you can add the following to your services.yaml file:

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services:
    AppEventSubscriberUserLoggedInSubscriber:
        tags:
            - { name: kernel.event_subscriber }


This will register the UserLoggedInSubscriber class as a service and tag it as a kernel event subscriber, which will cause Symfony to automatically register it as a listener for the UserLoggedInEvent event.