rails_admin and cancancan undefined method `accessible_by' for Product:Class

Question

I am new to ruby-on-rails and i am looking for a way to have my rails_admin dashboard accessible only by superadmin users. I discovered that the rails_admin gem is fully compatible with another gem: cancancan, used for managing authorizations.

I followed this guide: https://github.com/sferik/rails_admin/wiki/Cancancan to configure rails_admin properly, and this is the result:

config/initializers/rails_admin.rb :

RailsAdmin.config do |config|
  # == Devise ==
  config.authenticate_with do
    warden.authenticate! scope: :user
  end
  config.current_user_method(&:current_user)

  # == CancanCan ==
  config.authorize_with :cancancan

  config.actions do
    dashboard                     # mandatory
    index                         # mandatory
    new
    export
    bulk_delete
    show
    edit
    delete
    show_in_app
  end
end

app/models/ability.rb :

class Ability
  include CanCan::Ability
  def initialize(user)
    user ||= User.new
    can :read, :all

    if user.superadmin_role?
      can :access, :rails_admin
      can :read, :dashboard
      can :manage, :all
    elsif user.admin_role? 
      can :manage, :all
    end
  end
end

When i created the project, i skipped active-records. For now, the only scaffold i made was for a class called Product.

I keep getting this error when navigating to localhost:3000/admin:

NoMethodError in RailsAdmin::MainController#dashboard

undefined method `accessible_by' for Product:Class

I cannot figure out where and how to define this "accessible_by" method. Moreover, i found that on this link https://github.com/CanCanCommunity/cancancan/wiki/Fetching-Records , is told that NOT using active records requires a model adapter.

I'm using on MacOS 11.15.6 and:

• Rails 6.0.2
• Rails_admin 2.0.2
• Cancancan 3.0.2
• Mongoid 7.0.5

Can someone help me understanding what am i doing wrong? Thanks:)

Answer 1

Ok, i got it!

I solved the problem with these steps:

• FIRST OF ALL: STOP rails server IF CURRENTLY RUNNING

• Install the cancancan-mongoid gem. Simply type gem 'cancancan-mongoid' in your Gemfile, UNDER the existing declaration of the cancancan gem. Then run bundle install . I referred to this page: https://github.com/CanCanCommunity/cancancan-mongoid

• Check that the order of the gems in your Gemfile looks like this:

mongoid
cancancan
cancancan-mongoid
rails_admin

The first three steps should solve the problem, but if it persists, proceed with this last step:

• Create a new file called cancan_mongoid.rb and place it in your config/initializers folder, then paste the full code shown here: https://gist.github.com/bowsersenior/561639

This worked for me: :)