method_missing and association_proxy in rails

Question

So, here's my problem. I currently am building a simple authentication system for a rails site. I have 3 classes for this: Person, Session, and Role. In my Person model I have defined method_missing to dynamically capture roles according to this guide.

In my application_controller I have some logic to deal with logins and log-outs, the result of which gives me the currently logged in user via: @user = @application_session.person Where @application_session is the current session

Now in one of my controllers, I don't want anyone to be able to do anything unless they are an admin, so I included: before_filter @user.is_an_admin?

This raises a NoMethodError, even though I have method_missing defined in my model. I tried defining is_an_admin?, having it always return true as a test, and that works.

According to this question, I think the problem might have something to do with proxy associations. When I run: puts @user.proxy_owner I get a session object, since each user (Person) can have many sessions, and I got my user (Person) from the current session.

I am very confused why @user.is_an_admin? is not calling the method_missing method in my Person controller. Please let me know if you need more information or code snippets.

I am using Rails 3 on Ruby 1.9

how is @user set? is there a filter before the before filter? — apneadiving, May 17 '11 at 21:56
yes, `@user` is set in a before_filter in the application_controller, than `@user.is_an_admin?` is called in the reports_controller. I also tried `@user.is_an_admin?` in the index method of that controller for debugging purposes and received the same error. — Trevor, May 18 '11 at 03:46

score 0 · Answer 1 · answered May 17 '11 at 21:57

0

I'd consider a method_missing an overkill for such task.

Now, if you have Session class, which belongs_to User, then you can have this:


class Session
  belongs_to :user, :extend => PermissionMixin
end

class User
  include PermissionMixin
end

module PermissionMixin
  def admin?
    if cond
      true
    else
     false
    end
  end
end

P.S. Check cancan, perhaps it'll suit your needs better.

answered May 17 '11 at 21:57

Roman

13,100
2
47
63

That would probably suit my immediate needs, but I want to build this to be expandable. I want to be able to add more user roles later, without having to write an "is_a_role?" method for each one. I'll take a look at cancan, thanks. – Trevor May 18 '11 at 03:50
You can have method_missing in this mixin, I just don't like the concept. – Roman May 18 '11 at 06:22

score 0 · Answer 2 · edited May 17 '13 at 18:01

I have solved this by moving the method_missing method to my application_controller.rb. I change the logic of the method a little to check for a user, and if found, dynamically check the role. If things were not kosher, I had the method redirect to root_url or return true if the user matched the requested roles.

Finally, in my reports controller, I used before_filter :is_an_admin? and got my desired results. However, I am still unclear as to why method_missing had to be defined in my application controller as opposed to directly in the Person (aka @user) model?

score 0 · Answer 3 · answered Jun 09 '11 at 16:33

0

I use a similar permissions check in my system to check the User > Role > Permissions association: User.current_user.can_sysadmin?

In my controllers I have to instead use: User.current_user.send('can_sysadmin?')

This may work for you as well.

answered Jun 09 '11 at 16:33

Matt

13,948
6
44
68

method_missing and association_proxy in rails

3 Answers3