Observers in Laravel

In Laravel, observers are classes that allow you to listen for and respond to model events like created, updated, and deleted. Centralizing this logic creates simpler, more maintainable code. It also helps coordinate event-related actions in an organized way.

Origin

Observers are part of Laravel's event system, which is designed to provide a consistent and efficient way to manage model-related events.

Why are Observers Used?

1. Centralizes Logic: Combines all event-handling logic for a model into a single observer class.
2. Promotes Code Reusability: The same observer can be used across numerous models, minimizing redundancy.
3. Improves maintainability: Event-related duties are offloaded, keeping models and controllers tidy.

Best Practices.

1. Limit Observer Responsibilities: To avoid overcomplication, assign each observer to handle only event-specific tasks.
2. Thoroughly test the observers: Write tests to check that all expected event-handling behaviors execute properly.
3. Avoid Using Heavy Logic in Observers: For complex tasks, delegate them to jobs, services, or other specific classes.

Example in Action

Create an observer:

php artisan make:observer UserObserver --model=User

In the observer class:

namespace App\Observers;

use App\Models\User;

class UserObserver
{
    public function creating(User $user)
    {
        $user->uuid = Str::uuid();
    }
}

Register the observer in the boot method of a service provider:

use App\Models\User;
use App\Observers\UserObserver;

public function boot(): void
{
	User::observe(UserObserver::class);
}

Alternatively, you can use the ObservedBy attribute on your Eloquent model.

use App\Observers\UserObserver;
use Illuminate\Database\Eloquent\Attributes\ObservedBy;
 
#[ObservedBy([UserObserver::class])]
class User extends Authenticatable
{
    //
}