Question

I have polymorphic models:

class Picture < ActiveRecord::Base
  belongs_to :imageable, :polymorphic => true  
end

class Service < ActiveRecord::Base
  has_many :pictures, :as => :imageable
end

class Product < ActiveRecord::Base
  has_many :pictures, :as => :imageable
end

In order to get my activeadmin model to work with both parents (Service and Product) I need to do something like:

ActiveAdmin.register Picture do
  def who_do_i_belong_to?
    uri = how_to_get_uri?
    if uri.match(/products/) 
      :product
    else
      :service
    end
  end

  belongs_to  who_do_i_belong_to?
end

The workaround seems to work. I only miss how to get the url/uri from inside the who_do_i_belong_to? method.

controller.controller_name # "admin/services", so it is not useful. 

Thank you in advanced.

Answer 1

If you want to have CRUD for your polymorphic nested resources (products/pictures and services/pictures), your application needs to have routes like /admin/products/:id/images and /admin/services/:id/images. The problem is that when you use belongs_to :parent in a register block, active_admin will only generate one nested route admin/parents/:id/child, whereas you need two. Furthermore, :parent can’t be determine by the current url, because the call belongs_to :parent itself is used to create the current url (the resource path).

To get around this, you can define the routes yourself in configs.rb

namespace :admin do
  resources :services do
    resources :pictures
  end

  resources :products do
    resources :pictures
  end
end

and tell active_admin to use these routes by writing controller.belongs_to :service, :product, polymorphic: true in your register block for Picture.

Source: https://github.com/gregbell/active_admin/issues/1183