I was experimenting with AngularJS and using Rails as a backend and needed to enable Access-Control-Allow-Origin for $http. Here is a simple snippet I created that does the trick. If you were doing this in production, I would assume Apache or Nginx would be the appropriate place for this code. However, this is just a POC.
# application_controller.rb after_filter :local_access_control_headers def local_access_control_headers headers['Access-Control-Allow-Origin'] = 'http://localhost:8000' headers['Access-Control-Request-Method'] = '*' end