Merge pull request #559 from ZogStriP/fix-exception-when-wrong-resource-type-in-url

[fixes #391] exception when wrong resource type in URL

app/controllers/application_controller.rb

@@ -93,7 +93,7 @@ class ApplicationController < ActionController::Base
 
   # If we are rendering HTML, preload the session data
   def preload_json
-    if request.format.html?
+    if request.format && request.format.html?
       if guardian.current_user
         guardian.current_user.sync_notification_channel_position
       end