Rails CanCan gem refactoring Ability class

Question

I have a around 13 models in my rails app, I use ability on all of them. My ability class has grown huge. I have different ability conditions on different CRUD actions which is making it hard to manage.

Can someone guide me on how I can refactor this..? Like, using modules or classes for making my ability class look neat.

Answer 1

Simple escenario: If you can split the permissions in several mutually exclusive sets, then you should check this proposal from @ryanb, CanCan creator, in which he splits the abilities into several different classes and then overwrites the current_ability method in the ApplicationController

How you can break up large Ability class in CanCan - Gists

More complex scenario: if you have several different overlapping permissions sets, you can try this approach:

# app/models/ability.rb

class Ability
  include CanCan::Ability

  def initialize(user)
    self.merge Abilities::Everyone.new(user)

    if user
      self.merge Abilities::Admin.new(user) if user.admin?
      self.merge Abilities::Authenticated.new(user)
    else
      self.merge Abilities::Guest.new(user)
    end
  end
end

# app/models/abilities/admin.rb
module Abilities
  class Admin
    include CanCan::Ability

    def initialize(user)
      # define abilities here ...
    end
  end
end

# app/models/abilities/everyone.rb
...

And so on for the rest of the files.