gistfile1.php

<?php

namespace Foo\SiteBundle\EventListener;

use Doctrine\Common\EventSubscriber;
use Doctrine\ORM\Event\LifecycleEventArgs;

use Gedmo\Sluggable\Util\Urlizer;

use Foo\SiteBundle\Entity\Category;

class SlugCreatorSubscriber implements EventSubscriber
{
    public function getSubscribedEvents()
    {
        return array(
            'prePersist',
            'preUpdate',
        );
    }

    public function prePersist(LifecycleEventArgs $args)
    {
        $this->createSlug($args);
    }

    public function preUpdate(LifecycleEventArgs $args)
    {
        $this->createSlug($args);
    }

    public function createSlug(LifecycleEventArgs $args)
    {
        $entity        = $args->getEntity();
        $entityManager = $args->getEntityManager();
        $uow           = $entityManager->getUnitOfWork();

        if ($entity instanceof Category && $args->hasChangedField('name')) {
            foreach ($entity->getPages() as $page) {

                $slug = $page->getSlug();
                $slug = str_replace(Urlizer::urlize($args->getOldValue('name')), Urlizer::urlize($args->getNewValue('name')), $slug);
                $page->setSlug($slug);

                $entityManager->persist($page);
                $meta = $entityManager->getClassMetadata(get_class($page));
                $uow->recomputeSingleEntityChangeSet($meta, $page);
            }
        }
    }
}