ActiveAdmin-StateMachine

This gem provides an easy integration between the awesome state_machine and active_admin gems.

Features

This gem provides you with a DSL extension to ActiveAdmin that allows you to easily define action item buttons for your resource to transition through your state_machine.

• Integration with ActiveAdmin authorization adapater layer - the button won't show if the user isn't authorized
• Provide custom permission to authorize against
• Provide confirmation message to prompt user before performing
• Button only shown if state_machine can transition
• Localizable button titles and flash messages
• Pass a block to customize the behavior

Installation

This gem requires both active_admin and state_machine. Add the gem to your Gemfile to get started and bundle.

gem 'active_admin-state_machine'

Usage

You will need to define a state_machine in a model, and have that model registered as a resource with ActiveAdmin.

A basic model

# app/models/post.rb
class Post < ActiveRecord::Base
  attr_accessible :body, :status, :title

  validates :title, presence: true, uniqueness: true
  validates :body, presence: true

  DRAFT = 'draft'
  REVIEWED = 'reviewed'
  PUBLISHED = 'published'

  state_machine :status, initial: DRAFT do
    event :peer_review do
      transition DRAFT => REVIEWED
    end

    event :publish do
      transition REVIEWED => PUBLISHED
    end
  end
end

Corresponding ActiveAdmin resource

ActiveAdmin.register Post do

  state_action :peer_review
  state_action :publish

  form do |f|
    f.inputs "Post Details" do
      f.input :title
      f.input :body
    end
    f.actions
  end

end

In the above example, the state_action method is defined by this gem and provides you with the following functionality:

1. The :peer_review is assumed to be an event in your state_machine definition on the Post model.
2. Calling state_action will add an action item button to your ActiveAdmin resource on the #show page, if the user is authorized to perform this action via the ActiveAdmin authorization adapter, and if the resource itself returns true to #can_peer_review?, which is provided by default with this event in state_machine.
3. Clicking the button will call #peer_review! on the resource, and redirect you back to smart_resource_url.
4. Fully localizable, provide translations for "posts.peer_review.label"for the button title and "posts.peer_review.flash.success for the flash message when completed.
5. You can pass a block to customize this behavior.

Custom Block

ActiveAdmin.register Post do

  state_action :peer_review

  # Block to be called when submitted
  state_action :publish do
    PostPublicationService.publish!(resource)
    flash[:notice] = "Post published"
    redirect_to collection_path
  end

end

Custom Permission

ActiveAdmin.register Post do

  # by default, permission would be :peer_review
  state_action :peer_review, permission: :read
end

Confirmation

ActiveAdmin.register Post do

  # Lookup 'posts.peer_review.prompt'
  state_action :peer_review, confirm: :true

  # Pass proc
  state_action :peer_review, confirm: ->{ I18n.t("posts.peer_review.confirm") }
end

Using without state_machine model

If you really want to use without a state_machine on your model, you essentially just need to provide the following methods, contining with our :peer_review example:

class Post < ActiveRecord::Base    
  def can_peer_review?
    author.present? && !published?
  end

  def peer_review!
    self.published_at = Time.now
    save!
  end
end