To figureout what differece between before_action and before_filter, we should understand what difference between action and filter.

1. An action is a method of a controller to which you can route to.
   For example, your user creation page might be routed to UsersController#new - new is the action in this route.

2. Filters run in respect to controller actions - before, after or around them.
   These methods can halt the action processing by redirecting or set up common data to every action in the controller.

3. Rails 4 –> _action
   Rails 3 –> _filter