dynamically set named_scope based on current_user

Question

Hey all, I keep getting the following error:

You have a nil object when you didn't expect it!
You might have expected an instance of Array.
The error occurred while evaluating nil.size

Based on the current user, when they navigate to a page, I want to limit them to what they can see based on their site. Problem is there is no association between site and user table directly. A contact has_one user (user information is stored in current_user variable). A site has_many contacts. And a site has_many students, where students table has a foreign key of site_id. So there is a link between students and site, so when the current user navigates to students page, they can only see students from same site as them. I can do this by hard coding a number in a named_scope to only display students for the site of the current_user. But different users will belong to different sites so when logged in, the site their associated with will change. That's the problem - to dynamically set that value in a named_scope. This is what I have:

StudentsController

def index_scoper
  if current_user.role_id == 8
    super.site_staff_limit while current_user[:site_id]
    # The problem is the user table has no site_id. There is no direct
    # link between the users table and sites table. However, there is
    # a link between users and contacts and then site and contacts and
    # then site and students, where students table has site_id.
  else
    super.with_state.with_site
  end
end

Student Model

named_scope :site_staff_limit, lambda {|site_id| {:conditions => {:site_id => site_id}}}

Thanks for any suggestions.

relationship between tables:

users: contact_id contact: primary key, contactable_id, contactable_type site: primary key student: site_id

User model belongs_to :contact

Contact model has_one :user belongs_to :contactable, :polymorphic => true, :dependent => :destroy

Site model has_many :contacts, :as => :contactable has_many :students

Students model belongs_to :site

This successfully limits the students by site: StudentsController def index_scoper if current_user.role_id == 8 super.site_staff_limit else super.with_state.with_site end end

Students model named_scope :site_staff_limit, :conditions => {:site_id => 1}

The problem is different users will belong to different sites, so they can only access student records of the site they belong to. I am having difficulty making that named_scope above dynamic enough to accomplish this.

Answer 1

You might be able to set up a link between users and sites, with a :through relationship.

Does the code you have provided work? Is there an error that occurs?