In rails >4.0.0 generators creates CRUD operations with
before_filter. It seems to do the same thing. So what’s the difference between these two?
It is just syntax difference, in rails app there is CRUD, and seven actions basically by name index, new, create, show, update, edit, destroy.
Rails 4 make it developer friendly to change syntax before filter to before action.
before_action call method before the actions which we declare, like
before_action :set_event, only: [:show, :update, :destroy, :edit]
set_event is a method which will call always before show, update, edit and destroy.
It is just a name change.
before_action is more specific, because it gets executed before an action.
before_filter/before_action: means anything to be executed before any action executes.
Both are same. they are just alias for each other as their behavior is same.
use only before_action with rspec-rails, capybara as before_filter will misbehave to give surprises during testing
class TodosController < ApplicationController before_filter :authenticate def index @todos = Todo.all end ## Rest of the code follows end
feature 'User creates todo' do scenario 'successfully' do sign_in click_on 'Add Todo' fill_in 'Title', with: "Buy Milk" click_on 'Submit' expect(page).to have_css '.todos li', text: "Buy Milk" end end
the expected failure is
NoMethodError: undefined method `authenticate' for #<TodosController:0x0000558b68573f48>
but before_filter gives…
ActionView::Template::Error: undefined method `each' for nil:NilClass
That is, somehow the hook runs without error and but the controller goes to view with a @todos uninitialized
Better save time, use non deprecated codes…
To figure out what is the difference between before_action and before_filter, we should understand the difference between action and filter.
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.
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.
Rails 4 –> _action
Rails 3 –> _filter