Some Drupal History

Everything was a node

• I entered the scene around 4.6
• Back then there was something called Flexinode
• That eventually became CCK for 4.7, 5.x, 6.x
• Views module came out around the same time

Drupal Utopia

Drupal Utopia

CCK + Views = FTW

Everything was a node

Users, Terms, Panels, Everything!

Something was missing.

• basically the stuff that didn't make it in to Drupal 7 core because of timing
• you need it to get the full benefit of Entities in Drupal 7
• gives you Views and Rules integration, and basic CRUD operations on your custom entities

Define your own PHP Class

Real objects... no more stdClass()

• This did not ship with Drupal core
• This IMO is the try power of entities
• Why is this such a cool feature? real objects
• What do you get with real objects? The ability for Encapsulation

Encapsulation

Entity Class

/**
 * @file
 * Tournament match class.
 */
class TourneyMatchEntity extends TourneyEntity {
  ...
  /**
   * Get the winner of the match
   */
  public function getWinner() {
    if (is_null($this->matchWinner)) {
      $this->matchWinner = $this->determineWinner();
    }
    return $this->matchWinner;
  }
  ...
}

Implementation code

/**
 * Get the winner of the match
 */
$match = tourney_match_load(1);

/**
 * Call method directly on object.
 */
$winner = $match->getWinner();

Encapsulation

• A language mechanism for restricting access to some of the object's components
• A language construct that facilitates the bundling of data with the methods (or other functions) operating on that data.[

Questions about Encapsulation?

Using a Base Class

class TourneyEntity extends Entity {
  ...
  public function save() {
    if ((isset($this->is_new) && $this->is_new) || $this->created == 0) {
      $this->created = time();
    }
    $this->changed = time();
    parent::save();
  }

  /**
   * Return the uri to the entity object
   */
  public function getUri() {
    return TourneyEntity::path($this->id, $this->entityType);
  }
  ...
}

Inheritance

Super powerful!

• How do you deal with similar data the needs different fields?
• Lets talk about creating another entity first.

Writing Views Handlers

Next session in Room G7

• As a side note, if you come to my next session in the next hour I'll be talking about extending the Views module and writing your own handlers... and this is exactly how you do it.... using Inheritance.

Questions about Inheritance?

Using Bundles

• All bundles share the same entity class
• How can I get a specific class per bundle?

Proxy Pattern

Define your Entity with the Proxy

/**
 * Implements hook_entity_info().
 */
function it_service_entity_info() {
  $info = array(
    'it_service' => array(
      'label' => t('IT Service'),
      'plural label' => t('IT Services'),
      'description' => t('A single service provided by IT Services.'),
      'entity class' => 'Drupal\it_service\Entity\ItServiceProxy',
      'controller class' => 'EntityAPIController',
      'base table' => 'it_service',
      'fieldable' => TRUE,
      ...
    )
  );
  return $info;
}

Proxy Class

namespace Drupal\it_service\Entity;
...
class ItServiceProxy extends ItServiceBase {

  protected $entityClass;
  protected $entityType = 'it_service';

  /**
   * ItServiceProxy constructor.
   */
  public function __construct(array $values, $entityType) {
    $values['type'] = !empty($this->type) ? $this->type : $values['type'];
    $this->type = $values['type'];
    if (is_null($this->entityClass)) {
      $this->makeEntity($values['type']);
    }
  }

  private function makeEntity($bundle) {
    $className = 'Drupal\it_service\Entity\\' . CaseConverter::toCamelCase($bundle);
    if (class_exists($className)) {
      $this->entityClass = new $className(['type' => $bundle], $this->entityType);
    }
    else {
      throw new \Exception(t('A class does not exist for @bundleName bundle.', ['@bundleName' => $className]));
    }
  }

  function __call($name, $args) {
    if (!method_exists($this->entityClass, $name)) return FALSE;

    $method = new \ReflectionMethod($this->entityClass, $name);
    return $method->invoke($this->entityClass, $args);
  }

}

Polymorphism in Drupal!

Bonus

Show me how to create an entity!

It's on GitHub!