events.md

Events

• Basic Usage
• Using Classes As Listeners
• Event Subscribers

Basic Usage

The Laravel Event class provides a simple observer implementation, allowing you to subscribe and listen for events in your application. The Laravel event facilities extend the Symfony\Component\EventDispatcher\EventDispatcher class.

Subscribing To An Event

Event::listen('user.login', function($event)
{
	$event->user->last_login = new DateTime;

	$event->user->save();
});

Firing An Event

$event = Event::fire('user.login', ['user' => $user]);

Note that the Event::fire method returns an Event object, allowing you to inspect the event payload after the listeners have been called.

You may also specify a priority when subscribing to events. Listeners with higher priority will be run first, while listeners that have the same priority will be run in order of subscription.

Subscribing To Events With Priority

Event::listen('user.login', 'LoginHandler', 10);

Event::listen('user.login', 'OtherHandler', 5);

Sometimes, you may wish to stop the propagation of an event to other listeners. You may do so using the $event->stop() method.

Stopping The Propagation Of An Event

Event::listen('user.login', function($event)
{
	// Handle the event...

	$event->stop();
});

Using Classes As Listeners

In some case, you may wish to use a class to handle an event rather than a Closure. Class event listeners will be resolved out of the Laravel IoC container, providing you the full power of dependency injection on your listeners.

Registering A Class Listener

Event::listen('user.login', 'LoginHandler');

By default, the handle method on the LoginHandler class will be called:

Defining An Event Listener Class

class LoginHandler {

	public function handle($event)
	{
		//
	}

}

If you do not wish to use the default handle method, you may specify the method that should be subscribed:

Specifying Which Method To Subscribe

Event::listen('user.login', 'LoginHandler@onLogin');

Event Subscribers

Event subscribers are classes that may subscribe to multiple events from within the class itself. Subscribers should extend the EventSubscriber class and define a subscribes method.

Defining An Event Subscriber

class UserEventHandler extends EventSubscriber {

	/**
	 * Handle user login events.
	 */
	public function onUserLogin($event)
	{
		//
	}

	/**
	 * Handle user logout events.
	 */
	public function onUserLogout($event)
	{
		//
	}

	/**
	 * Register the listeners for the subscriber.
	 *
	 * @return array
	 */
	public static function subscribes()
	{
		return [
			'user.login' => [
				['onUserLogin', 10],
			],
			'user.logout' => [
				['onUserLogout', 10],
			],
		];
	}

}

Once the subscriber has been defined, it may be registered with the Event class.

Registering An Event Subscriber

Event::subscribe(new UserEventHandler);

Removing An Event Subscriber

Event::unsubscribe($subscriber);