Issue #2872793 by peaton, rakesh.gectcr, phenaproxima, heddn, vasi: Create...

Issue #2872793 by peaton, rakesh.gectcr, phenaproxima, heddn, vasi: Create Entity Exists Process Plugin

core/modules/migrate/src/Plugin/migrate/process/EntityExists.php

+<?php
+
+namespace Drupal\migrate\Plugin\migrate\process;
+
+use Drupal\Core\Entity\EntityInterface;
+use Drupal\Core\Entity\EntityStorageInterface;
+use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
+use Drupal\migrate\Plugin\MigrationInterface;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\ProcessPluginBase;
+use Drupal\migrate\Row;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * This plugin checks if a given entity exists.
+ *
+ * Example usage with configuration:
+ * @code
+ *   field_tags:
+ *     plugin: entity_exists
+ *     source: tid
+ *     entity_type: taxonomy_term
+ * @endcode
+ *
+ * @MigrateProcessPlugin(
+ *  id = "entity_exists"
+ * )
+ */
+class EntityExists extends ProcessPluginBase implements ContainerFactoryPluginInterface {
+
+  /**
+   * The entity storage.
+   *
+   * @var \Drupal\Core\Entity\EntityStorageInterface
+   */
+  protected $storage;
+
+  /**
+   * EntityExists constructor.
+   *
+   * @param array $configuration
+   *   A configuration array containing information about the plugin instance.
+   * @param string $plugin_id
+   *   The plugin ID.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param $storage
+   *   The entity storage.
+   */
+  public function __construct(array $configuration, $plugin_id, $plugin_definition, EntityStorageInterface $storage) {
+    parent::__construct($configuration, $plugin_id, $plugin_definition);
+    $this->storage = $storage;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
+    return new static(
+      $configuration,
+      $plugin_id,
+      $plugin_definition,
+      $container->get('entity_type.manager')->getStorage($configuration['entity_type'])
+    );
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function transform($value, MigrateExecutableInterface $migrate_executable, Row $row, $destination_property) {
+    if (is_array($value)) {
+      $value = reset($value);
+    }
+
+    $entity = $this->storage->load($value);
+    if ($entity instanceof EntityInterface) {
+      return $entity->id();
+    }
+    return FALSE;
+  }
+
+}

core/modules/migrate/tests/src/Kernel/Plugin/EntityExistsTest.php

+<?php
+
+namespace Drupal\Tests\migrate\Kernel\Plugin;
+
+use Drupal\KernelTests\KernelTestBase;
+use Drupal\migrate\MigrateExecutableInterface;
+use Drupal\migrate\Row;
+use Drupal\user\Entity\User;
+
+/**
+ * Tests the EntityExists process plugin.
+ *
+ * @group migrate
+ */
+class EntityExistsTest extends KernelTestBase {
+
+  /**
+   * {@inheritdoc}
+   */
+  public static $modules = ['migrate', 'system', 'user'];
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+    $this->installSchema('system', ['sequences']);
+    $this->installEntitySchema('user');
+  }
+
+  /**
+   * Test the EntityExists plugin.
+   */
+  public function testEntityExists() {
+    $user = User::create([
+      'name' => $this->randomString(),
+    ]);
+    $user->save();
+    $uid = $user->id();
+
+    $plugin = \Drupal::service('plugin.manager.migrate.process')
+      ->createInstance('entity_exists', [
+        'entity_type' => 'user',
+      ]);
+    $executable = $this->prophesize(MigrateExecutableInterface::class)->reveal();
+    $row = new Row();
+
+    // Ensure that the entity ID is returned if it really exists.
+    $value = $plugin->transform($uid, $executable, $row, 'buffalo');
+    $this->assertSame($uid, $value);
+
+    // Ensure that the plugin returns FALSE if the entity doesn't exist.
+    $value = $plugin->transform(420, $executable, $row, 'buffalo');
+    $this->assertFalse($value);
+
+    // Make sure the plugin can gracefully handle an array as input.
+    $value = $plugin->transform([$uid, 420], $executable, $row, 'buffalo');
+    $this->assertSame($uid, $value);
+  }
+
+}