Doctrine2 Event Listener: persisting in onFlush()

Another Doctrine2 Post. This time we’re taking a look on Event Listeners/Subscribers. Event Listeners are a real powerful thing in Doctrine2. Besides LifeCycleCallbacks they can be used if you’ll want to scan through your Entity i.e. for specialized standard field. Also implementing a global Versionable behaviour (since that is no longer a native Doctrine behaviour) ist very easy to do inside Event Listeners.

My motivation for this quick blog post is just to give people a gist how to use EventListeners because the documentation is -again- a pain in the ass. Im just using onFlush() here, since preUpdate() is somehow not called by SonataDoctrineORMAdminBundle which i’m using to mainly manage my Entities.

Lets start by creating a EventListener in My/Bundle/Listener/MyEventListener.php

<?php namespace My\Bundle\Listener; use Doctrine\Common\EventSubscriber; use Doctrine\ORM\Events; use Doctrine\ORM\Event\OnFlushEventArgs; use Doctrine\ORM\Mapping\ClassMetadata; use My\Bundle\Entity\Event; class MyEventListener { private $em = null; private $uow = null; private $attachedEvents; public function onFlush(OnFlushEventArgs $args) { $this -> em = $args -> getEntityManager(); $eventManager = $this -> em -> getEventManager(); // Remove event, if we call $this->em->flush() now there is no infinite recursion loop! $eventManager -> removeEventListener('onFlush', $this); $this -> uow = $this -> em -> getUnitOfWork(); //Iterate through Insertions: foreach ($this->uow->getScheduledEntityInsertions() as $entity) { //Get the plain ClassName without Namespace $className = join('', array_slice(explode('\\', get_class($entity)), -1)); $meta = $this -> em -> getClassMetadata(get_class($entity)); $value = $meta -> getReflectionProperty('myEntityFieldName') -> getValue($entity); //... create your Entity... $newEvent = new Event; $newEvent->setName('...'); //... $this -> em -> persist($newEvent); $this -> em -> flush(); } // recalculate changeset, since we might messed up the relations $this -> em -> getUnitOfWork() -> recomputeSingleEntityChangeSet($meta, $entity); } //We can also iterate through planned deletions foreach ($this->uow->getScheduledEntityDeletions() AS $entity) { $className = join('', array_slice(explode('\\', get_class($entity)), -1)); //Search for old dependencies and delete them too... $events = $this -> em -> getRepository('MyBundle:Event') -> findBy('myProperty'=>'value'); foreach ($events as $entity) { $this -> em -> remove($entity); } } } $this -> em -> flush(); } //Or even react on updates: foreach ($this->uow->getScheduledEntityUpdates() as $key => $entity) { $className = join('', array_slice(explode('\\', get_class($entity)), -1)); $meta = $this -> em -> getClassMetadata(get_class($className)); //ChangeSet is an array of key - array pairs. //$changeSet['fieldname'] => array(0 => 'oldValue', 1 => 'newValue') //if the target Value is i.e. a date, the indices 0 and 1 are i.e. DateTime Objects $changeSet = $this -> uow -> getEntityChangeSet($entity); //You can modify your Entities based on the Changes here.. //After Persisting: $this->uow->computeChangeSet($meta, $entity) } } //Re-attach since we're done $eventManager -> addEventListener('onFlush', $this); } }

Now all that is left to do is to attach the Event Listener to DI. If you’re using Symfony2 you’ll just need to update your app/config/config.yml

For further information feel free to take a look at the beautiful Doctrine2 Documentation, which I obviously love so much.

Benedikt Wolters

the missing T_PAAMAYIM_NEKUDOTAYIM

Doctrine2 Event Listener: Persisting in onFlush()

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