diff --git a/S3/S3.py b/S3/S3.py
index d4cac8f9..6a77d890 100644
--- a/S3/S3.py
+++ b/S3/S3.py
@@ -728,12 +728,14 @@ def content_type(self, filename=None, is_dir=False):
         return content_type
 
     def add_encoding(self, filename, content_type):
+        if not filename:
+            return False
         if 'charset=' in content_type:
            return False
         exts = self.config.add_encoding_exts.split(',')
         if exts[0]=='':
             return False
-        parts = filename.rsplit('.',2)
+        parts = filename.rsplit('.', 1)
         if len(parts) < 2:
             return False
         ext = parts[1]