Events¶

There are situations where you might want to react before or after an entity is modified. For example hashing the password of an user object instead of storing it directly in clear text in the database. Or you want to get an E-Mail every time someone deletes a library object.

This is what events are for. You can define closures which are executed in certain moments and can even interrupt the modification of the data.

This is how you define an event which is executed before an entity is created:

The boot method of the kernel is a possible place to define an event:

public function boot() {
    parent::boot();
    $this->getContainer()->get('crudlex.service')->getData('library')->getEvents()->push('before', 'create', function(CRUDlex\Entity $entity) {
        // Do something with the entity which is about to be saved.
        return true;
    });
}

$app['crud']->getData('library')->getEvents()->push('before', 'create', function(CRUDlex\Entity $entity) {
    // Do something with the entity which is about to be saved.
    return true;
});

This code should go in your setup directly after the ServiceProvider is registered.

push takes three parameters:

The moment of the event, can be:
- before
- after
The action of the event, can be:
- create: On entity creation
- update: On entity update
- delete: On entity deletion
- createFiles: On created entity files handling
- updateFiles: On updated entity files handling
- deleteFiles: On deleted entity files handling
- deleteFile: On deleting a file of an entity
The closure to execute on this event. Signature: function(CRUDlex\Entity $entity)

You can push as many events for a moment and an action as you like. They will be executed in the order they were added.

The before events must return a boolean. The first event returning false is canceling the whole action and so the entity doesn’t get created, updated or deleted.

With pop, the last added event of the given moment and action is removed from the list and the closure is returned:

$closure = $this->getContainer()->get('crudlex.service')->getData('library')->getEvents()->pop('before', 'create');

$closure = $app['crud']->getData('library')->getEvents()->pop('before', 'create');

If no more events are available, pop will return null.