public static String getUploadUrl(ImageRef ref) { BlobstoreService blobstoreService = BlobstoreServiceFactory.getBlobstoreService(); return blobstoreService.createUploadUrl( "/backend/image-post-upload?ref=" + BaseEncoding.base64().encode(ref.toByteArray()), UploadOptions.Builder.withGoogleStorageBucketName(getBucket())); }