Rendering different layouts in Rails depending on whether the user is logged in

Assuming we have two different layout files:

• application.html.erb - for logged in users
• guest.html.erb - for guest users

We can add the following bit of code in our base ApplicationController:

class ApplicationController < ActionController::Base
  layout :layout

  private

  def layout
    user_signed_in? ? 'application' : 'guest'
  end
end

Assuming all our custom controllers extend ApplicationController as is the default convention, then our views will use the application layout when the user is signed in and the guest layout when they aren't signed in.