Pundit Scoping for Model Ownership through a Join table - Rails 4 - mysql

Question

I'm associating users with given firms through a join table because I need to be able to have a bunch of users with every firm and vice versa.
class User
has_many :firm_connections, dependent: :destroy
has_many :firms, through: :firm_connections
end
class FirmConnection
belongs_to :user
belongs_to :firm
end
class Firm
has_many :firm_connections
has_many :users, through: :firm_connections
end
My question is, when a user hits the index page for firms, how do I scope it to only show what those users are associated with?
class FirmPolicy < ApplicationPolicy
class Scope < Scope
def resolve
if user.admin?
scope.all
else
scope.where #only the firms associated with that user
end
end
end
Do I need to create a scope at the firm level that accepts a #user? Or can I do this all directly inline? I could hack something together, but haven't wrapped my head around pundit yet, so any direction would be greatly appreciated!
like this:
def self.associated_with(user)
all.select { |m| m.users.include?(user) }
end

Answer 1

This should work for you
class Firm
def index
#firms = policy_scope(Firm)
end
end
class FirmPolicy < ApplicationPolicy
class Scope < Scope
def resolve
if user.admin?
scope.all
else
user.firms #only the firms associated with that user
end
end
end
end
The policy doesn't always have to call it the way that you think, it just has to return something (for scopes, almost always an ActiveRecord::Relation, for regular, true or false). You could do
scope.includes(:firm_connections).where(firm_connections: { user_id: user.id })
but that's not as readable (IMO).