8-custom-actions.md

Custom Controller Actions

Active Admin allows you to override and modify the underlying controller which is generated for you. There are helpers to add collection and member actions, or you can drop right in to the controller and modify its behavior.

Collection Actions

A collection action is a controller action which operates on the collection of resources. This method adds both the action to the controller as well as generating a route for you.

To add a collection action, use the collection_action method:

ActiveAdmin.register Post do

  collection_action :import_csv, method: :post do
    # Do some CSV importing work here...
    redirect_to collection_path, notice: "CSV imported successfully!"
  end

end

This collection action will generate a route at /admin/posts/import_csv pointing to the Admin::PostsController#import_csv controller action.

Member Actions

A member action is a controller action which operates on a single resource.

For example, to add a lock action to a user resource, you would do the following:

ActiveAdmin.register User do

  member_action :lock, method: :put do
    resource.lock!
    redirect_to resource_path, notice: "Locked!"
  end

end

This will generate a route at /admin/users/:id/lock pointing to the Admin::UserController#lock controller action.

Controller Action HTTP Verb

The collection_action and member_actions methods both accept the :method argument to set the HTTP verb for the controller action and route.

The generated routes will be scoped to the given method you pass in. By default your action will use the GET verb.

Rendering in Custom Actions

Custom controller actions support rendering within the standard Active Admin layout.

ActiveAdmin.register Post do

  # /admin/posts/:id/comments
  member_action :comments do
    @comments = resource.comments
    # This will render app/views/admin/posts/comments.html.erb
  end

end

If you would like to use the same view syntax as the rest of Active Admin, you can use the Arbre file extension: .arb.

For example, create app/views/admin/posts/comments.html.arb with:

table_for assigns[:post].comments do
  column :id
  column :author
  column :body do |comment|
    simple_format comment.body
  end
end

Custom Action Items

To include your own action items (like the New, Edit and Delete buttons), add an action_item block. For example, to add a "View on site" button to view a blog post:

action_item only: :show do
  link_to 'View on site', post_path(post) if post.published?
end

Actions items also accept the :if option to conditionally display them:

action_item only: :show, if: proc{ current_admin_user.super_admin? } do
  "Only display this to super admins on the show screen"
end

Page Titles

The page title for the custom action will be the translated version of the controller action name. For example, a member_action named "upload_csv" will look up a translation key of active_admin.upload_csv. If none are found, it defaults to the name of the controller action.

If this doesn't work for you, you can always set the @page_title instance variable in your controller action to customize the page title.

ActiveAdmin.register Post do

  member_action :comments do
    @comments   = resource.comments
    @page_title = "#{resource.title}: Comments" # Sets the page title
  end

end

Modifying the Controller

The generated controller is available to you within the registration block by using the controller method.

ActiveAdmin.register Post do

  controller do
    # This code is evaluated within the controller class

    def define_a_method
      # Instance method
    end
  end

end