diff --git a/src/app/attachment/controllers/AttachmentController.php b/src/app/attachment/controllers/AttachmentController.php
index 1a5f68641c3c60b5e085c2e32c4af16c8a9095a7..f5cf6300bb1caa002ae894af32b724d48144dffb 100755
--- a/src/app/attachment/controllers/AttachmentController.php
+++ b/src/app/attachment/controllers/AttachmentController.php
@@ -476,7 +476,7 @@ class AttachmentController
 
         $data = $request->getQueryParams();
         if ($data['mode'] == 'base64') {
-            return $response->withJson(['encodedDocument' => base64_encode($fileContent)]);
+            return $response->withJson(['encodedDocument' => base64_encode($fileContent), 'format' => pathinfo($pathToDocument, PATHINFO_EXTENSION)]);
         } else {
             $finfo    = new \finfo(FILEINFO_MIME_TYPE);
             $mimeType = $finfo->buffer($fileContent);
diff --git a/src/app/resource/controllers/ResController.php b/src/app/resource/controllers/ResController.php
index 40a768036c1508186b8e8b9daa976ad7e31de054..98ce18ea1900d612d1f9b077549ba4efa9e995a7 100755
--- a/src/app/resource/controllers/ResController.php
+++ b/src/app/resource/controllers/ResController.php
@@ -425,7 +425,7 @@ class ResController extends ResourceControlController
 
         $data = $request->getQueryParams();
         if ($data['mode'] == 'base64') {
-            return $response->withJson(['encodedDocument' => base64_encode($fileContent)]);
+            return $response->withJson(['encodedDocument' => base64_encode($fileContent), 'format' => pathinfo($pathToDocument, PATHINFO_EXTENSION)]);
         } else {
             $finfo    = new \finfo(FILEINFO_MIME_TYPE);
             $mimeType = $finfo->buffer($fileContent);