Using scopes in my Pundit policy (Rails 5)

Question

How to use scopes, defined in the model, in my Pundit policy?

In my model I have a scope:

scope :published, ->{ where.not(published_at: nil )}

And in my Pundit policy I have

class CompanyPolicy < ApplicationPolicy
    def index?
        true
    end
    def create?
        user.present?
    end
    def new?
        true
    end
    def show?
        true
    end
    def update?
      user.present? && user == record.user
    end
end

How can I use my scope in the Pundit policy? I would like to show it only if it's "published", something like this, which doesn't work at the moment:

class CompanyPolicy < ApplicationPolicy
    def show
       record.published?
    end
end

score 0 · Accepted Answer · answered Sep 09 '18 at 14:31

Scopes are Class methods, you can't call them on instances.

You have to define a published? instance method too:

def published?
  published_at.present?
end

You could use the scope if you ask if the record exists on the given scope with:

User.published.exists?(user.id)

And it will return true if the scope includes the user id, but I wouldn't recommend that, it requires an extra query to the database to get something that you can know from the user instance you already have.

Using scopes in my Pundit policy (Rails 5)

1 Answers1