如何在Laravel 5.5中实现事件

Question

The Laravel Eloquent Event docs give this example:

namespace App;

use App\Events\UserSaved;
use App\Events\UserDeleted;
use Illuminate\Notifications\Notifiable;
use Illuminate\Foundation\Auth\User as Authenticatable;

class User extends Authenticatable
{
    use Notifiable;

    /**
     * The event map for the model.
     *
     * @var array
     */
    protected $dispatchesEvents = [
        'saved' => UserSaved::class,
        'deleted' => UserDeleted::class,
    ];
}

I simply want to know what would go in a UserSaved::class to, let's say, add a hash id on the initial save. The docs are frustratingly opaque at this point!

Answer 1

In any of your model event classes, just do this:

For example: App\Events\UserSaved.php

<?php

namespace App\Events;

use Illuminate\Queue\SerializesModels;

class UserSaved
{

    use SerializesModels;

    /**
     * @var \App\User
     */
    public $user;

    public function __construct($user)
    {
        // All dispatched model events will receive an instance
        // of the model itself. Usually, we'll just assign
        // it as a property of this event class
        $this->user = $user;
    }
}

Dispatched event are supplied with the model instance, as shown in the source code:

Documentation: Defining Events

So at the later time when your listeners caught this event, they will have an instance of this UserSaved object, and you can just access user from $userSaved->user.