Communication between Symfony and Doctrine on different projects

Question

The application is split into several projects.

The database is a separate project and use doctrine (without Symfony).

The API is a symfony project which uses the database project as dependencies (vendor).

I would like to create events at the Symfony level by listening to doctrine event, but Symfony does not know any doctrine because it is external to its project.

Do you have an idea ?

Thanks

question from:https://stackoverflow.com/questions/65933652/communication-between-symfony-and-doctrine-on-different-projects

Answer 1

If I understand correctly, you have two Symfony applications - the first one with a database and the second one that uses this database via API. It's not possible to implement Doctrine events listener within the second application, as it's not aware of Doctrine entities of the first application. However, you can solve this problem by using Symfony Messenger Component. The first application would dispatch messages on every Doctrine event and the second application would subscribe to those messages and handle them.

Something like this. The first application side.

<?php

declare(strict_types=1);

namespace AppEventListener;

use AppEntityUser;
use AppMessageUserChangedNotification;
use DoctrinePersistenceEventLifecycleEventArgs;
use SymfonyComponentMessengerMessageBusInterface;

class UserChangedNotifier
{
    private MessageBusInterface $bus;

    public function __construct(MessageBusInterface $bus)
    {
        $this->bus = $bus;
    }

    public function postUpdate(User $user, LifecycleEventArgs $event): void
    {
        $this->bus->dispatch(new UserChangedNotification($user));
    }
}

The second application side.

<?php

declare(strict_types=1);

namespace AppMessageHandler;

use AppMessageUserChangedNotification;
use SymfonyComponentMessengerHandlerMessageHandlerInterface;

class UserChangedNotificationHandler implements MessageHandlerInterface
{
    public function __invoke(UserChangedNotification $message)
    {
        // ... do something with the message, e.g. dispatch Symfony event
    }
}