CakePHP 3: How to create custom model callbacks?

Question

Need good start point to create custom model callbacks. For specific part of application i can't use default cakephp lifecycle callbacks (beforeSave, afterSave,..) because table is large. In controller I create more methods wich partial update records, for example users 4 step registrations.

How to create custom model callbacks for example beforeRegister used only before new user account created?

Answer 1

Rather than using callback methods which are more of a CakePHP 2.x concept, I would recommend dispatching Events which you can then listen to.

The book has a chapter about Events.

Specifically, you'll want to dispatch your new event, using a name which includes the layer you're working in.

// Inside a controller
$event = new \Cake\Event\Event(
    // The name of the event, including the layer and event
    'Controller.Registration.stepFour', 
    // The subject of the event, usually where it's coming from, so in this case the controller
    $this, 
    // Any extra stuff we want passed to the event
    ['user' => $userEntity] 
);
$this->eventManager()->dispatch($event);

Then you can listen to the event in another part of your application. For me personally, in most cases I like to create a specific listener class, in my src/Lib/Listeners folder.

namespace App\Lib\Listeners;

class RegistrationListener implements EventListenerInterface
{
    public function implementedEvents()
    {
        return [
            'Controller.Registration.stepOne' => 'stepOne'
            'Controller.Registration.stepFour' => 'stepFour'
    }

    public function stepOne(\Cake\Event\Event $event, \Cake\Datasource\EntityInterface $user)
    {
        // Process your step here
    }
}

Then you need to bind the listener. To do this I tend to use the global Event Manager instance and do it in my AppController, so that it can listen everywhere, but if you're just working with a single RegistrationsController you might want to attach it just to that one controller.

Attaching globally, probably in your AppController::initialize()

EventManager::instance()->on(new \App\Lib\RegistrationListener());

Attaching to a controller, probably in your Controller::initialize()

$this->eventManager()->on(new \App\Lib\RegistrationListener())