fix(preview): handle unavailable previews as no content

Signed-off-by: Sebastian Krupinski <krupinski01@gmail.com>

lib/Controllers/DefaultController.php

@@ -989,10 +989,7 @@ class DefaultController extends ControllerAbstract {
             isset($data['variant']) && is_string($data['variant']) ? $data['variant'] : 'inline',
         );
         if ($preview === null) {
-            return new JsonResponse([
+            return new Response('', Response::HTTP_NO_CONTENT);
-                'status' => 'error',
-                'error' => ['code' => 404, 'message' => 'Preview unavailable'],
-            ], Response::HTTP_NOT_FOUND);
         }
 
         return new StreamedResponse($preview->resource->stream(), Response::HTTP_OK, [

src/services/transceive.ts

@@ -199,6 +199,9 @@ export async function transceiveBlob<TRequest>(operation: string, data: TRequest
   await fetchWrapper.post(API_URL, request, {
     headers: { 'Accept': '*/*' },
     onStream: async (response: Response) => {
+      if (response.status === 204) {
+        throw new Error(`[${operation}] Preview unavailable`);
+      }
       blob = await response.blob();
     },
   });