hostnet/entity-revision-component

Listens to an event so revisions can be made

1.1.4 2019-07-24 10:52 UTC

README

Documentation

What is the Entity Revision Component?

The Entity Revision Component is a library that utilizes the Entity Tracker Component and lets you hook in to the entityChanged event.

This component lets you automatically store revisions for a set of entities per flush.

Requirements

The revision component requires a minimum of php 5.4 and runs on Doctrine2. For specific requirements, please check composer.json.

Installation

Installing is pretty easy, this package is available on packagist. You can register the package locked to a major as we follow Semantic Versioning 2.0.0.

Example

    "require" : {
        "hostnet/entity-revision-component" : "1.*"
    }

Note: You can use dev-master if you want the latest changes, but this is not recommended for production code!

Documentation

How does it work?

It works by putting the @Revision annotation and RevisionableInterface on your Entity and registering the listener on the entityChanged event, assuming you have already configured the Entity Tracker Component.

For a usage example, follow the setup below.

Note: this component works very well with the Entity Mutation Component. This combination is ideal to go back in time based on revisions.

Setup

  • You have to add @Revision to your entity
  • You have to add the RevisionableInterface to your entity
  • You need a Revision Entity

Registering the events

Here's an example of a very basic setup. Setting this up will be a lot easier if you use a framework that has a Dependency Injection Container.

It might look a bit complicated to set up, but it's pretty much setting up the tracker component for the most part. If you use it in a framework, it's recommended to create a framework specific configuration package for this to automate this away.

Note: If you use Symfony2, you can take a look at the hostnet/entity-tracker-bundle. This bundle is designed to configure the services for you.

use Acme\Bundle\AcmeBundle\AcmeRevisionFactory;
use Hostnet\Component\EntityRevision\Resolver\RevisionResolver;
use Hostnet\Component\EntityTracker\Listener\EntityChangedListener;
use Hostnet\Component\EntityTracker\Provider\EntityAnnotationMetadataProvider;
use Hostnet\Component\EntityTracker\Provider\EntityMutationMetadataProvider;

/* @var $em \Doctrine\ORM\EntityManager */
$event_manager = $em->getEventManager();

// default doctrine annotation reader
$annotation_reader = new AnnotationReader();

// setup required providers
$mutation_metadata_provider   = new EntityMutationMetadataProvider($annotation_reader);
$annotation_metadata_provider = new EntityAnnotationMetadataProvider($annotation_reader);
$logger = ...; // instance of LoggerInterface from the psr/log package, optional argument
 
// pre flush event listener that uses the @Revision annotation
$entity_changed_listener = new EntityChangedListener(
    $mutation_metadata_provider,
    $annotation_metadata_provider,
    $logger
);

// the resolver is used to find the correct annotation
$revision_resolver = new RevisionResolver($annotation_metadata_provider);

// this factory will provide the revision and as author Henk
$revision_factory = new AcmeRevisionFactory('Henk');

// creating the revision listener
$revision_listener = new RevisionListener($revision_resolver, $revision_factory);

$event_manager->addEventListener('preFlush', $entity_changed_listener);
$event_manager->addEventListener('postFlush', $revision_listener);
$event_manager->addEventListener('entityChanged', $revision_listener);

Note: The RevisionListener must be registered on both the onFlush and entityChanged. Because the revisions are grouped per flush, you must also make sure that the RevisionListener is registered before the EntityChangedListener. If this is not done, you will recieve unexpected results.

Creating a Revision Entity

Revisions are stored in the database, thus need an Entity. You're free to decide how to store it but you should implement the RevisionInterface on it.


use Doctrine\ORM\Mapping as ORM;
use Hostnet\Component\EntityRevision\RevisionInterface;

/**
 * @ORM\Entity
 */
class Revision implements RevisionInterface
{
       
    /**
     * @ORM\...
     */
    private $author;
    
    /**
     * @ORM\...
     */
    private $created_at;
    
    public function __construct($author, \DateTime $created_at)
    {
        $this->author     = $author;
        $this->created_at = $created_at;
    }
    
    public function getUser()
    { 
        return $this->author;
    }

    public function getCreatedAt()
    {
        return $this->created_at;
    }
}

Configuring the Entity

All we have to do now is put the @Revision annotation and RevisionableInterface on our Entity.


use Doctrine\ORM\Mapping as ORM;
use Hostnet\Component\EntityRevision\RevisionableInterface;

/**
 * @ORM\Entity
 * @Revision
 */
class MyEntity implements RevisionableInterface
{
    /**
     * The current revision of the contact person
     *
     * @ORM\ManyToOne(targetEntity="Revision")
     * @ORM\JoinColumn(name="revision_id", referencedColumnName="id")
     * @var Revision
     */
    private $revision;
    
    public function setRevision(RevisionInterface $revision)
    {
        $this->revision = $revision;
    }
    
    public function getRevision()
    {
        return $this->revision;
    }
}

Creating the AcmeRevisionFactory

The factory is responsible for providing a revision Entity. You're free to fill in what you want and not obligated to using a constructor like in this example. The only requirement is that it creates a Revision.


namespace Acme\Bundle\AcmeBundle;

use Hostnet\Component\EntityRevision\Factory\RevisionFactoryInterface;

class AcmeRevisionFactory implements RevisionFactoryInterface
{
    private $author;
    
    public function __construct($author)
    {
        $this->author = $author;
    }

    public function createRevision(\DateTime $created_at)
    {
        return new Revision($this->author, $created_at);
    }
}

What's next?

All you have to do now is change multiple entities with @Revision and they will be grouped by a Revision Entity.

// imagine all instances to be Revisionable
$user->setName('Henk');
$address->setNumber('42');
$em->flush();
var_dump($user->getRevision() === $address->getRevision()); // true