Active Admin scopes for each instance of a related model

activeadmin, heroku, ruby, ruby-on-rails

Solution

Here is an actual solution to this problem ... Altho using filters instead is more desirable stability and maintenance wise, this looks nicer in ActiveAdmin and is more user friendly since scopes become nice looking tabs.

It is a bit of a hack, but it is a viable solution where appropriate:

The trick is to update the scopes in a before_filter on the controllers index action.

This could get bad if you have many scopes created on a resource (altho you can easily set some limits)

ActiveAdmin.register Project do
  menu :priority => 1
  index do
    column :name
    column :company_name
    column :status
    column :projection do |project|
      number_to_currency project.projection
    end
    column :updated_at
    default_actions
  end

  scope :all
  scope :working, :default => true do |projects|
    projects.where(:status => 'working')
  end

  controller do
    before_filter :update_scopes, :only => :index

    def update_scopes
      resource = active_admin_config

      Manager.all.each do |m|
        next if resource.scopes.any? { |scope| scope.name == m.first_name }
        resource.scopes << (ActiveAdmin::Scope.new m.first_name do |projects|
          projects.where(:manager_id => m.id)
        end)
      end

      # try something like this for deletions (untested)
      resource.scopes.delete_if do |scope|
        !(Manager.all.any? { |m| scope.name == m.first_name } || ['all', 'working'].include?(scope.name)) # don't delete other scopes you have defined
      end

    end
  end
end

Problem

Original source