the missing T_PAAMAYIM_NEKUDOTAYIM

Moved Site to GitHub and Octopress

I’ve moved my original site to Octopress for the sake of niceness. This sake of niceness includes:

Markdown Syntax, very easy non-verbose writing of blogposts
NoSQL local file based storage, no overhead, no scripting language required, high-performance content delivery
Github Pages distribution, no hosting required

Oct 1st, 2012

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.

Mar 27th, 2012

Symfony, doctrine2, php, symfony2

Pagerank Algorithmn Studies

Hier sind meine Ausarbeitung und die Folien zu meinem Proseminar “Algorithms and Data Structures” beim i2 RWTH-Aachen.

Mar 25th, 2012

PageRank

Doctrine2 One-To-Many, Unidirectional With Join Table Association Mapping

Since the Doctrine 2.0 Documentation for this seems to be kinda fucked up at the moment, here is a working exampe of a One-To-Many, Unidirectional with Join-Table Association Mapping

Scenario

A driver can have many documents, but a document has no direct Entity relation to a driver.

Solution

Use Many-To-Many to encode it properly.

Im using annotations with the ORM-Namespace since its embedded in Symfony2. Note that One-To-Many is coded throughout Many-To-Many but the unique index is set for the join table.

In my POV thats kinda confusing since there is a @One-To-Many relationship, but whatever!

Mar 24th, 2012

doctrine2, php, symfony2