Fix multi-file media to allow image fields only on image derivatives.

modules/islandora_image/src/Plugin/Action/GenerateImageDerivativeFile.php

@@ -6,7 +6,10 @@
 use Drupal\islandora\Plugin\Action\AbstractGenerateDerivativeMediaFile;
 
 /**
- * Emits a Node for generating derivatives event.
+ * Emits a Media for generating derivatives event.
+ *
+ * Attaches the result as a file in an image field on the emitting
+ * Media ("multi-file media").
  *
  * @Action(
  *   id = "generate_image_derivative_file",
@@ -24,7 +27,6 @@ public function defaultConfiguration() {
     $config['path'] = '[date:custom:Y]-[date:custom:m]/[media:mid]-ImageService.jpg';
     $config['mimetype'] = 'application/xml';
     $config['queue'] = 'islandora-connector-houdini';
-    $config['destination_media_type'] = 'file';
     $config['scheme'] = $this->config->get('default_scheme');
     return $config;
   }
@@ -34,9 +36,30 @@ public function defaultConfiguration() {
    */
   public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
     $form = parent::buildConfigurationForm($form, $form_state);
-    $form['mimetype']['#description'] = $this->t('Mimetype to convert to (e.g. application/xml, etc...)');
+    $map = $this->entityFieldManager->getFieldMapByFieldType('image');
+    $file_fields = $map['media'];
+    $file_options = array_combine(array_keys($file_fields), array_keys($file_fields));
+    $file_options = array_merge(['' => ''], $file_options);
+    // @todo figure out how to write to thumbnail, which is not a real field.
+    //   see https://github.com/Islandora/islandora/issues/891.
+    unset($file_options['thumbnail']);
+
+    $form['destination_field_name'] = [
+      '#required' => TRUE,
+      '#type' => 'select',
+      '#options' => $file_options,
+      '#title' => $this->t('Destination Image field'),
+      '#default_value' => $this->configuration['destination_field_name'],
+      '#description' => $this->t('This Action stores the derivative in an
+       Image field. If you need to store the result in a File field, use
+       "Generate a Derivative File for Media Attachment". Selected target field
+       must be an additional field, not the media\'s main storage field.
+       Selected target field must be present on the media.'),
+    ];
+
     $form['mimetype']['#value'] = 'image/jpeg';
-    $form['mimetype']['#type'] = 'hidden';
+    $form['mimetype']['#description'] = 'Mimetype to convert to. Must be
+    compatible with the destination image field.';
     return $form;
   }
 

src/Controller/MediaSourceController.php

@@ -280,8 +280,7 @@ public function attachToMedia(
    */
   public function attachToMediaAccess(AccountInterface $account, RouteMatch $route_match) {
     $media = $route_match->getParameter('media');
-    $node = $this->utils->getParentNode($media);
-    return AccessResult::allowedIf($node->access('update', $account) && $account->hasPermission('create media'));
+    return AccessResult::allowedIf($media->access('update', $account));
   }
 
 }

src/MediaSource/MediaSourceService.php

@@ -268,8 +268,8 @@ public function putToNode(
         'uri' => $content_location,
         'filename' => $this->fileSystem->basename($content_location),
         'filemime' => $mimetype,
-        'status' => FILE_STATUS_PERMANENT,
       ]);
+      $file->setPermanent();
 
       // Validate file extension.
       $source_field_config = $this->entityTypeManager->getStorage('field_config')->load("media.$bundle.$source_field");
@@ -349,8 +349,8 @@ public function putToMedia(
         'uri' => $content_location,
         'filename' => $this->fileSystem->basename($content_location),
         'filemime' => $mimetype,
-        'status' => FILE_STATUS_PERMANENT,
       ]);
+      $file->setPermanent();
 
       // Validate file extension.
       $bundle = $media->bundle();

src/Plugin/Action/AbstractGenerateDerivativeMediaFile.php

@@ -7,7 +7,10 @@
 use Drupal\Core\Url;
 
 /**
- * Emits a Node for generating derivatives event.
+ * Emits a Media for generating derivatives event.
+ *
+ * Attaches the result as a file in a file field on the emitting
+ * Media ("multi-file media").
  *
  * @Action(
  *   id = "generate_derivative_file",
@@ -98,15 +101,23 @@ public function buildConfigurationForm(array $form, FormStateInterface $form_sta
     $image_options = array_combine(array_keys($image_fields), array_keys($image_fields));
 
     $file_options = array_merge(['' => ''], $file_options, $image_options);
+
+    // @todo figure out how to write to thumbnail, which is not a real field.
+    //   see https://github.com/Islandora/islandora/issues/891.
+    unset($file_options['thumbnail']);
+
     $form['event']['#disabled'] = 'disabled';
 
     $form['destination_field_name'] = [
       '#required' => TRUE,
       '#type' => 'select',
       '#options' => $file_options,
-      '#title' => $this->t('Destination File field Name'),
+      '#title' => $this->t('Destination File field'),
       '#default_value' => $this->configuration['destination_field_name'],
-      '#description' => $this->t('File field on Media Type to hold derivative.  Cannot be the same as source'),
+      '#description' => $this->t('This Action stores a derivative file
+       in a File or Image field on a media. The destination field
+       must be an additional field, not the media\'s main storage field.
+       Selected destination field must be present on the media.'),
     ];
 
     $form['args'] = [