diff --git a/app/controller/Server.php b/app/controller/Server.php
index e6c79b4..5b0ec77 100644
--- a/app/controller/Server.php
+++ b/app/controller/Server.php
@@ -103,7 +103,7 @@ class Server
             return redirect('/');
         }
         if($source->type==0){
-            $etag='"'.md5($source->source).'"';
+            $etag='W/"'.md5($source->source).'"';
             $if_none_match = $request->header('If-None-Match',null);
             if($if_none_match==$etag){
                 return response('',304);