Issue #3413192 by erik_petra: Create FileTransformBase class

src/Plugin/Transform/Field/FileTransformBase.php

+<?php
+
+namespace Drupal\transform_api\Plugin\Transform\Field;
+
+use Drupal\Core\Entity\EntityTypeManagerInterface;
+use Drupal\Core\Field\FieldDefinitionInterface;
+use Drupal\Core\File\FileUrlGeneratorInterface;
+use Drupal\transform_api\FieldTransformBase;
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+ * Base class for File field transform plugins.
+ */
+abstract class FileTransformBase extends FieldTransformBase {
+
+  /**
+   * File url generator.
+   *
+   * @var \Drupal\Core\File\FileUrlGeneratorInterface
+   */
+  protected $fileUrlGenerator;
+
+  /**
+   * The entity type manager.
+   *
+   * @var \Drupal\Core\Entity\EntityTypeManagerInterface
+   */
+  protected $entityTypeManager;
+
+  /**
+   * Constructs a FieldTransformBase object.
+   *
+   * @param string $plugin_id
+   *   The plugin_id for the transform.
+   * @param mixed $plugin_definition
+   *   The plugin implementation definition.
+   * @param \Drupal\Core\Field\FieldDefinitionInterface $field_definition
+   *   The definition of the field to which the transform is associated.
+   * @param array $settings
+   *   The transform settings.
+   * @param string $label
+   *   The transform label display setting.
+   * @param string $transform_mode
+   *   The transform mode.
+   * @param array $third_party_settings
+   *   Any third party settings.
+   * @param \Drupal\Core\File\FileUrlGeneratorInterface $file_url_generator
+   *   The file url generator.
+   * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
+   *   The entity type manager.
+   */
+  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $transform_mode, array $third_party_settings, FileUrlGeneratorInterface $file_url_generator, EntityTypeManagerInterface $entity_type_manager) {
+    parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $transform_mode, $third_party_settings);
+
+    $this->fileUrlGenerator = $file_url_generator;
+    $this->entityTypeManager = $entity_type_manager;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
+    return new static($plugin_id, $plugin_definition, $configuration['field_definition'], $configuration['settings'], $configuration['label'], $configuration['transform_mode'], $configuration['third_party_settings'], $container->get('file_url_generator'), $container->get('entity_type.manager'));
+  }
+
+  /**
+   * Loads file entity.
+   *
+   * @param $fid
+   *
+   * @return \Drupal\file\FileInterface|null
+   *
+   * @throws \Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException
+   * @throws \Drupal\Component\Plugin\Exception\PluginNotFoundException
+   */
+  protected function loadFile($fid) {
+    /** @var \Drupal\file\FileInterface|null $file */
+    $file = $this->entityTypeManager->getStorage('file')->load($fid);
+
+    return $file;
+  }
+
+}

src/Plugin/Transform/Field/FileURLTransform.php

@@ -17,7 +17,7 @@ use Drupal\transform_api\FieldTransformBase;
  *  }
  * )
  */
-class FileURLTransform extends FieldTransformBase {
+class FileURLTransform extends FileTransformBase {
 
   /**
    * {@inheritdoc}
@@ -30,10 +30,10 @@ class FileURLTransform extends FieldTransformBase {
         // File ID.
         $fid = $item->getValue()['target_id'];
         // Load file.
-        $file = File::load($fid);
+        $file = $this->loadFile($fid);
         $file_uri = $file->getFileUri();
 
-        $values[] = \Drupal::service('file_url_generator')->generateString($file_uri);
+        $values[] = $this->fileUrlGenerator->generateString($file_uri);
       }
       else {
         $values[] = NULL;

src/Plugin/Transform/Field/FileUrlSizeTransform.php

@@ -2,12 +2,7 @@
 
 namespace Drupal\transform_api\Plugin\Transform\Field;
 
-use Drupal\Core\Field\FieldDefinitionInterface;
 use Drupal\Core\Field\FieldItemListInterface;
-use Drupal\Core\File\FileUrlGenerator;
-use Drupal\file\Entity\File;
-use Drupal\transform_api\FieldTransformBase;
-use Symfony\Component\DependencyInjection\ContainerInterface;
 
 /**
  * Transform field plugin for file field types as Urls.
@@ -20,30 +15,7 @@ use Symfony\Component\DependencyInjection\ContainerInterface;
  *  }
  * )
  */
-class FileUrlSizeTransform extends FieldTransformBase {
-
-  /**
-   * File url generator.
-   *
-   * @var \Drupal\Core\File\FileUrlGenerator
-   */
-  protected $fileUrlGenerator;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function __construct($plugin_id, $plugin_definition, FieldDefinitionInterface $field_definition, array $settings, $label, $transform_mode, array $third_party_settings, FileUrlGenerator $file_url_generator) {
-    parent::__construct($plugin_id, $plugin_definition, $field_definition, $settings, $label, $transform_mode, $third_party_settings);
-
-    $this->fileUrlGenerator = $file_url_generator;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition) {
-    return new static($plugin_id, $plugin_definition, $configuration['field_definition'], $configuration['settings'], $configuration['label'], $configuration['transform_mode'], $configuration['third_party_settings'], $container->get('file_url_generator'));
-  }
+class FileUrlSizeTransform extends FileTransformBase {
 
   /**
    * {@inheritdoc}
@@ -56,7 +28,7 @@ class FileUrlSizeTransform extends FieldTransformBase {
         // File ID.
         $fid = $item->getValue()['target_id'];
         // Load file.
-        $file = File::load($fid);
+        $file = $this->loadFile($fid);
         $file_uri = $file->getFileUri();
 
         $values[] = [