diff --git a/ftdetect/roast.vim b/ftdetect/roast.vim
index 4a23e6b..412cfc6 100644
--- a/ftdetect/roast.vim
+++ b/ftdetect/roast.vim
@@ -1 +1,5 @@
-au BufRead,BufNewFile *.roast,*.http setf roast
+au BufRead,BufNewFile *.roast setf roast
+
+if get(g:, 'roast_http_ext', 0) == 1
+  au BufRead,BufNewFile *.http setf roast
+endif