CanCan

Rails Admin is fully compatible with CanCan, an authorization framework to limit which actions a user can perform on each model.

Setup CanCan

If you haven't already, setup CanCan by adding it to your Gemfile and running the bundle command.

gem "cancan"

Next, run the generator to create an Ability class. This is where authorization rules are defined.

rails g cancan:ability

Add to Rails Admin

To use it with Rails Admin, add this to an initializer.

# in config/initializers/rails_admin.rb

RailsAdmin.config do |config|
  config.authorize_with :cancan
end

At this point, all authorization will fail and no one will be able to access the admin pages. To grant access, add this to Ability#initialize.

can :access, :rails_admin

Then, you will need to grant access on each of the models. Here's a complete example of an Ability class which defines different permissions depending upon the user's role.

class Ability
  include CanCan::Ability
  def initialize(user)
    can :read, :all                   # allow everyone to read everything
    if user && user.admin?
      can :access, :rails_admin       # only allow admin users to access Rails Admin
      if user.role? :superadmin
        can :manage, :all             # allow superadmins to do anything
      elsif user.role? :manager
        can :manage, [User, Product]  # allow managers to do anything to products and users
      elsif user.role? :sales
        can :update, Product, :hidden => false  # allow sales to only update visible products
      end
    end
  end
end

How you define the user roles is completely up to you. See the CanCan Documentation for more information.

Handle Unauthorized Access

If the user authorization fails, a CanCan::AccessDenied exception will be raised. You can catch this and modify its behavior in the ApplicationController.

class ApplicationController < ActionController::Base
  rescue_from CanCan::AccessDenied do |exception|
    redirect_to main_app.root_path, :alert => exception.message
  end
end

CanCan::AuthorizationNotPerformed exception

remove check_authorization from app/controllers/application_controller.rb, use load_and_authorize_resource on every controllers instead.

RailsAdmin verbs

RailsAdmin use 2 customs verbs:

:history
:show_in_app

They get overridden by :manage in Cancan.