class EntityFetchByField

class EntityFetchByField extends RulesActionBase implements ContainerFactoryPluginInterface {
    
    /**
     * The entity type manager.
     *
     * @var \Drupal\Core\Entity\EntityTypeManagerInterface
     */
    protected $entityTypeManager;
    
    /**
     * Constructs a EntityFetchByField object.
     *
     * @param array $configuration
     *   A configuration array containing information about the plugin instance.
     * @param string $plugin_id
     *   The plugin ID for the plugin instance.
     * @param mixed $plugin_definition
     *   The plugin implementation definition.
     * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
     *   The entity type manager service.
     */
    public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityTypeManagerInterface $entity_type_manager) {
        parent::__construct($configuration, $plugin_id, $plugin_definition);
        $this->entityTypeManager = $entity_type_manager;
    }
    
    /**
     * {@inheritdoc}
     */
    public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
        return new static($configuration, $plugin_id, $plugin_definition, $container->get('entity_type.manager'));
    }
    
    /**
     * {@inheritdoc}
     */
    public function refineContextDefinitions(array $selected_data) {
        if ($type = $this->getContextValue('type')) {
            $this->pluginDefinition['provides']['entity_fetched']
                ->setDataType("entity:{$type}");
        }
    }
    
    /**
     * Executes the action with the given context.
     *
     * @param string $type
     *   The entity type id.
     * @param string $field_name
     *   Name of the field by which the entity is to be selected.
     * @param mixed $field_value
     *   The field value of the entity to be fetched.
     * @param int $limit
     *   Limit on the maximum number of fetched entities.
     */
    protected function doExecute($type, $field_name, $field_value, $limit = NULL) {
        $storage = $this->entityTypeManager
            ->getStorage($type);
        // When retrieving entities, if $limit is not set there is no need to use
        // the query object directly.
        if (is_null($limit)) {
            $entities = $storage->loadByProperties([
                $field_name => $field_value,
            ]);
        }
        else {
            $query = $storage->getQuery();
            $entity_ids = $query->accessCheck(TRUE)
                ->condition($field_name, $field_value, '=')
                ->range(0, $limit)
                ->execute();
            $entities = $storage->loadMultiple($entity_ids);
        }
        // Set provided value.
        // @todo Ensure that the provided context has the correct entity type.
        $this->setProvidedValue('entity_fetched', $entities);
    }

}