Events, Listeners, and Observers

Event-Driven Architecture

Events decouple your application components. When a post is published, you might notify subscribers, update search, and post to social media — without the Post model knowing about any of it.

Creating Events and Listeners

php artisan make:event PostPublished
php artisan make:listener NotifySubscribers --event=PostPublished

class PostPublished
{
    use Dispatchable, SerializesModels;
    public function __construct(public Post $post) {}
}

class NotifySubscribers implements ShouldQueue
{
    public function handle(PostPublished $event): void
    {
        Subscriber::active()->each(function ($sub) use ($event) {
            Mail::to($sub->email)->queue(new NewPostMail($event->post));
        });
    }
}

Registering Listeners

// In AppServiceProvider
Event::listen(PostPublished::class, NotifySubscribers::class);
Event::listen(PostPublished::class, IndexPostForSearch::class);

Dispatching Events

PostPublished::dispatch($post);

Model Observers

For Eloquent lifecycle hooks:

php artisan make:observer PostObserver --model=Post

class PostObserver
{
    public function created(Post $post): void
    {
        Cache::forget('recent_posts');
    }

    public function updated(Post $post): void
    {
        Cache::forget("post_{$post->slug}");
        Cache::forget('sitemap_xml');
    }

    public function deleted(Post $post): void
    {
        Cache::forget("post_{$post->slug}");
    }
}

// Register in AppServiceProvider
Post::observe(PostObserver::class);

Events and observers make your code open to extension without modification — the Open/Closed Principle in action.