Issue #959: Improve IIIF manifest generation performance.

Store image dimensions in with and height fields.

modules/islandora_iiif/src/Plugin/views/style/IIIFManifest.php

@@ -214,7 +214,7 @@ class IIIFManifest extends StylePluginBase {
           $canvas_id = $iiif_base_id . '/canvas/' . $entity->id();
           $annotation_id = $iiif_base_id . '/annotation/' . $entity->id();
 
-          [$width, $height] = $this->getCanvasDimensions($iiif_url, $image, $mime_type);
+          [$width, $height] = $this->getCanvasDimensions($iiif_url, $image, $mime_type, $entity);
 
           $tmp_canvas = [
             // @see https://iiif.io/api/presentation/2.1/#canvas
@@ -272,11 +272,19 @@ class IIIFManifest extends StylePluginBase {
    *   The image field.
    * @param string $mime_type
    *   The mime type of the image.
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The image entity.
    *
    * @return [string]
    *   The width and height of the image.
    */
-  protected function getCanvasDimensions(string $iiif_url, FieldItemInterface $image, string $mime_type) {
+  protected function getCanvasDimensions(string $iiif_url, FieldItemInterface $image, string $mime_type, $entity) {
+    if ($entity->hasField('field_height') && !$entity->get('field_height')->isEmpty() && $entity->hasField('field_width') && !$entity->get('field_width')->isEmpty()) {
+      $width = $entity->get('field_width')->value;
+      $height = $entity->get('field_height')->value;
+    }
+    else {
+      // Try to fetch the IIIF metadata for the image.
       try {
         $info_json = $this->httpClient->get($iiif_url)->getBody();
         $resource = json_decode($info_json, TRUE);
@@ -305,6 +313,13 @@ class IIIFManifest extends StylePluginBase {
           }
         }
       }
+    }
+    if ($entity->hasField('field_height') && $entity->get('field_height')->isEmpty() && $entity->hasField('field_width') && $entity->get('field_width')->isEmpty()) {
+      $entity->set('field_width', $width);
+      $entity->set('field_height', $height);
+      $entity->save();
+    }
+
     return [$width, $height];
   }