Difference between actions and filters in rails

Question

I am a beginner and I have a really basic question confusing me ie

• What is the difference between actions and filters?

for example we have before_action and after_action in rails 4 but we call them filters, why? I read somewhere that filters are for controllers and actions are for models, is that it?

Answer 1

OK, so this is how I see things:

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. For example:

before_action :require_logged_out, only: [:new]
def require_logged_out
  redirect_to user_path(current_user) if logged_in?
end

So here, require_logged_out is a filter which runs before the new action of the users controller.

3: Lastly I'll mention that in Rails 3.x *_action filters have been defined via *_filter . for example, you'd set a before_filter and not a before_action .

I think that should wrap things up for you regarding actions and filters in rails.

Answer 2

Actions are the rails 4.0 name for filters. They do the exact same thing but before_action is a clearer name for the behavior.

Here is where the name was changed in code. https://github.com/rails/rails/commit/9d62e04838f01f5589fa50b0baa480d60c815e2c

Here is a link to another discussion on the matter. Rails 4: before_filter vs. before_action