Entities are now classed objects using a defined interface

Summary

• Entities are now classed objects that implement the Drupal\entity\EntityInterface.
• The default implementation is the Drupal\entity\Entity class.
• Entity create, update, and delete functionality is now provided via the interface.
• Users, nodes, comments, taxonomy terms and vocabularies have been converted to extend the new base class and interface.
• Other core entity types will be converted in #1368394: Convert all core entities to classed objects.
• The base class and interface do not yet support revisioning or language handling; support for these features will be added going forward.
• entity_uri() and entity_label() are now deprecated and will be removed.
• Full roadmap for entity changes: #1346204: [META] Drupal 8 Entity API improvements.

Impact on modules

Contributed and custom modules should:

• Convert custom entity types to either use the base Drupal\entity\Entity class (for simple entity types) or to extend the Drupal\entity\Entity class with a custom class.
• Use the common interface for CRUD operations.
• Use the common interface for property getters and setters.
• Replace use of entity_uri() and entity_label() with the corresponding methods provided in the interface.
• New entities should be created with entity_create(), directly using the PHP new keyword and a specific class is discouraged.

API Changes

Added interfaces

• Drupal\entity\EntityInterface
• Drupal\entity\EntityStorageControllerInterface (implemented by EntityDatabaseStorageController)
  Added public methods (compared to the Drupal 7 DrupalEntityControllerInterface):
  • create()
  • delete()
  • save()

Added and changed classes

Added API functions

• entity_delete_multiple()
• entity_create()

Example implementation

• Custom entity that extends the base class and adds a property:
  
  <?php
namespace Drupal*my_module;

use Drupal*entity*Entity;

class MyForum extends Entity {
  /**
   * @var int
   */
  public $threadId = 0;
}
?>
• Custom storage controller that extends the controller class and overrides postSave():
  
  <?php
namespace Drupal*my_module;

use Drupal*entity*EntityDatabaseStorageController;
use Drupal*entity*EntityInterface;

class MyForumStorageController extends EntityDatabaseStorageController {
  /**
   * Overrides Drupal\entity\EntityDatabaseStorageController::postSave().
   */
  protected function postSave(EntityInterface $forum) {
    if ($forum->threadId) {
      module_invoke_all('forum_thread_save', $forum);
    }
  }
}
?>
• Entity usage:
  
  <?php
// Create a new forum instance.
$forum = entity_create('myforum', array('threadId' => 5));
// Save entity to the database.
$forum->save();
// Do some arbitrary processing of the entity.
myforum_process_forum_data($forum);
// Save entity again.
$forum->save();
?>