Laravel Application Helper Function: event

event($event, $payload = [], $halt = false)

The event helper is a convenient way to dispatch a particular $event to its listeners. An optional $payload of data can also be supplied when dispatching the event. When the event is dispatched, all its listeners will be called and any responses from the listener will be added to an array. The array of responses is generally the return value of the event function.

If the $halt parameter is set to true, the dispatcher will stop calling listeners after any of the listeners return a value that is not null. If no listeners have returned a response and all listeners were called, the event function will return null.

The following examples will highlight the various ways to use the event function:

 1<?php
 2 
 3/**
 4 * The following code is simply creating a new event class
 5 * to signal that a video was watched.
 6 */
 7 
 8namespace App\Events;
 9 
10use App\Video;
11use App\Events\Event;
12use Illuminate\Queue\SerializesModels;
13 
14class VideoWasWatched extends Event
15{
16    use SerializesModels;
17 
18    public $video;
19 
20    /**
21     * Create a new event instance.
22     *
23     * @param  Video  $video
24     * @return void
25     */
26    public function __construct(Video $video)
27    {
28        $this->video = $video;
29    }
30}

An event can be fired by the name of a class like so:

1<?php
2 
3event('\App\Events\VideoWasWatched', $video);

Alternatively, an event can be fired by instantiating a new instance of the event class itself:

1<?php
2 
3event(new VideoWasWatched($video));

In the above example, a $payloadwas not supplied. This is because the event instance itself will become the payload. It is equivalent to the following:

1<?php
2 
3$event = new VideoWasWatched($video);
4event('App\Events\VideoWasWatched', $event);

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