docs/8-custom-actions.md
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redirect_from: /docs/8-custom-actions.html
---
# 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:
```ruby
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:
```ruby
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.
## HTTP Verbs
The `collection_action` and `member_action` methods both accept the `:method`
argument to set the HTTP verb for the controller action and route.
Sometimes you want to create an action with the same name, that handles multiple
HTTP verbs. In that case, this is the suggested approach:
```ruby
member_action :foo, method: [:get, :post] do
if request.post?
resource.update! foo: params[:foo] || {}
head :ok
else
render :foo
end
end
```
## Rendering
Custom controller actions support rendering within the standard Active Admin
layout.
```ruby
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:
```ruby
table_for assigns[:post].comments do
column :id
column :author
column :body do |comment|
simple_format comment.body
end
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.
```ruby
ActiveAdmin.register Post do
member_action :comments do
@comments = resource.comments
@page_title = "#{resource.title}: Comments" # Sets the page title
end
end
```
# Action Items
To include your own action items (like the New, Edit and Delete buttons), add an
`action_item` block. The first parameter is just a name to identify the action,
and is required. For example, to add a "View on site" button to view a blog
post:
```ruby
action_item :view, only: :show do
link_to 'View on site', post_path(resource) if resource.published?
end
```
Actions items also accept the `:if` option to conditionally display them:
```ruby
action_item :super_action,
only: :show,
if: proc{ current_admin_user.super_admin? } do
"Only display this to super admins on the show screen"
end
```
By default action items are positioned in the same order as they defined (after default actions),
but it’s also possible to specify their position manually:
```ruby
action_item :help, priority: 0 do
"Display this action to the first position"
end
```
Default action item priority is 10.
# Modifying the Controller
The generated controller is available to you within the registration block by
using the `controller` method.
```ruby
ActiveAdmin.register Post do
controller do
# This code is evaluated within the controller class
def define_a_method
# Instance method
end
end
end
```