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28.

Doctrine Listeners on Update

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Doctrine Listeners on Update

But what if a user updates their password? Hmm, our listener isn’t called on updates, so the encoded password can never be updated. Crap!

Add a second tag to services.yml to listen on the preUpdate event and create the preUpdate method by copying from prePersist:

# src/Yoda/UserBundle/Resources/config/services.yml
services:
    doctrine.user_listener:
        class: Yoda\UserBundle\Doctrine\UserListener
        arguments: ["@security.encoder_factory"]
        tags:
            - { name: doctrine.event_listener, event: prePersist }
            - { name: doctrine.event_listener, event: preUpdate }

Add a die statement so we can test things:

// src/Yoda/UserBundle/Doctrine/UserListener.php
// ...

public function preUpdate(LifecycleEventArgs $args)
{
    die('UUPPPPPDDAAAAAATING!');

    $entity = $args->getEntity();
    if ($entity instanceof User) {
        $this->handleEvent($entity);
    }
}

Also, if the plainPassword field isn’t set, don’t do any work. This will happen if a User is being saved, but their password isn’t being changed:

// src/Yoda/UserBundle/Doctrine/UserListener.php
// ...

private function handleEvent(User $user)
{
    if (!$user->getPlainPasword()) {
        return;
    }

    // ...
}

Testing the Update

We can’t test this easily because we don’t have a way to update users yet. No worries. Just open up the play script from episode 1. We already have a user here - just change his plain password and save:

// play.php
// ...

use Doctrine\ORM\EntityManager;

$em = $container->get('doctrine')
    ->getEntityManager()
;

$wayne = $em
    ->getRepository('UserBundle:User')
    ->findOneByUsernameOrEmail('wayne');

$wayne->setPlainPassword('new');
$em->persist($user);
$em->flush();

Ok, run the play script:

php play.php

Hmm, it didn’t hit our die statement. Our listener function wasn’t called.

Gotcha 1: Event Listeners don’t fire on Unchanged Objects

It’s a gotcha! The plainPassword property isn’t saved to Doctrine, but we do use it to set the password field, which is persisted.

The problem is that when we change only the plainPassword field, the User looks “unmodified” to Doctrine. So, instead of calling our listener, it does nothing.

To fix the issue, let’s nullify the password field whenever plainPassword is set:

// src/Yoda/UserBundle/Entity/User.php
// ...

public function setPlainPassword($plainPassword)
{
    $this->plainPassword = $plainPassword;

    $this->setPassword(null);

    return $this;
}

Since password is persisted to Doctrine, this is enough to trigger all the normal behavior. Our listener should make sure password is set to the encoded value, and not left blank.

Now run the play script again. Great, it hits the die statement. Remove that and try it again.

No errors, so let’s try to login. Yes!

We just saw prePersist and preUpdate and Doctrine has several other events you can find on their website. Symfony also has events, which are fired at different points during the request-handling process.

Fortunately, Symfony’s event system is very similar to Doctrine’s. Don’t you love it when good ideas are shared?