• Robert Speicher's avatar
    Merge branch 'refactor/add-policies' into 'master' · e71cd7a3
    Robert Speicher authored
    Refactor ability.rb into Policies
    
    ## What does this MR do?
    Factors out `ability.rb` into a new abstraction - the "policy" (stored in `app/policies`). A policy is a class named `#{class_name}Policy` (looked up automatically as needed) that implements `rules` as follows:
    
    ``` ruby
    class ThingPolicy < BasePolicy
      def rules
        @user # this is a user to determine abilities for, optionally nil in the anonymous case
        @subject # this is the subject of the ability, guaranteed to be an instance of `Thing`
        can! :some_ability # grant the :some_ability permission
        cannot! :some_ability # ensure that :some_ability is not allowed. this overrides any `can!` that is called before or after
        delegate! @subject.other_thing # merge the abilities (can!) and prohibitions (cannot!) from `@subject.other_thing`
        can? :some_ability # test whether, so far, :some_ability is allowed
      end
    
      def anonymous_rules
        # optional. if not implemented `rules` is called where `@user` is nil. otherwise this method is called when `@user` is nil.
      end
    end
    ```
    
    See merge request !5796
    e71cd7a3
merge_request.rb 21.3 KB