Allow using PORO decorators

features/decorators.feature

@@ -26,6 +26,25 @@ Feature: Decorators
     And I should see "A very unique post"
     And I should see "No"
 
+  Scenario: Index page with PORO decorator
+    Given a configuration of:
+    """
+      ActiveAdmin.register Post do
+        decorate_with PostPoroDecorator
+
+        index do
+          column(:id)
+          column(:title)
+          column(:decorator_method)
+          column(:starred)
+        end
+      end
+    """
+    When I am on the index page for posts
+    Then I should see "A method only available on the PORO decorator"
+    And I should see "A very unique post"
+    And I should see "No"
+
   Scenario: Show page with decorator
     Given a configuration of:
     """

features/index/batch_actions.feature

@@ -60,6 +60,23 @@ Feature: Batch Actions
     Then I should see a flash with "Successfully deleted 2 posts"
     And I should see 3 posts in the table
 
+  Scenario: Use default (destroy) batch action on a PORO decorated resource
+    Given 5 posts exist
+    And an index configuration of:
+    """
+      ActiveAdmin.register Post do
+        decorate_with PostPoroDecorator
+      end
+    """
+    When I check the 2nd record
+    And I check the 4th record
+    And I follow "Batch Actions"
+    Then I should see the batch action :destroy "Delete Selected"
+
+    Given I submit the batch action form with "destroy"
+    Then I should see a flash with "Successfully deleted 2 posts"
+    And I should see 3 posts in the table
+
   @javascript
   Scenario: Use default (destroy) batch action on a nested resource
     Given I am logged in

lib/active_admin/resource_controller.rb

@@ -26,6 +26,8 @@ class ResourceController < BaseController
     include ViewHelpers::DownloadFormatLinksHelper
     extend ResourceClassMethods
 
+    helper_method :apply_collection_decorator
+
     def self.active_admin_config=(config)
       if @active_admin_config = config
         defaults resource_class: config.resource_class,

lib/active_admin/resource_controller/data_access.rb

@@ -27,8 +27,7 @@ def self.included(base)
         :filtering,
         :scoping,
         :includes,
-        :pagination,
-        :collection_decorator
+        :pagination
       ].freeze
 
       # Retrieve, memoize and authorize the current collection from the db. This

lib/active_admin/resource_controller/decorators.rb

@@ -77,9 +77,9 @@ def self.wrap!(parent, name)
         # Draper::CollectionDecorator was introduced in 1.0.0
         # Draper::Decorator#collection_decorator_class was introduced in 1.3.0
         def self.find_collection_decorator(decorator)
-          if Dependency.draper? '>= 1.3.0'
+          if Dependency.draper?('>= 1.3.0') && decorator <= Draper::Decorator
             decorator.collection_decorator_class
-          elsif Dependency.draper? '>= 1.0.0'
+          elsif Dependency.draper?('>= 1.0.0') && decorator <= Draper::Decorator
             draper_collection_decorator
           else
             decorator

lib/active_admin/views/pages/index.rb

@@ -137,7 +137,7 @@ def render_index
                                            per_page: per_page,
                                            pagination_total: pagination_total) do
             div class: 'index_content' do
-              insert_tag(renderer_class, config, collection)
+              insert_tag(renderer_class, config, apply_collection_decorator(collection))
             end
           end
         end

spec/support/rails_template.rb

@@ -21,6 +21,7 @@
 
 copy_file File.expand_path('templates/models/post.rb', __dir__), 'app/models/post.rb'
 copy_file File.expand_path('templates/post_decorator.rb', __dir__), 'app/models/post_decorator.rb'
+copy_file File.expand_path('templates/post_poro_decorator.rb', __dir__), 'app/models/post_poro_decorator.rb'
 
 generate :migration, 'create_blog_posts title:string body:text published_date:date author_id:integer ' +
   "position:integer custom_category_id:integer starred:boolean foo_id:integer #{timestamps}"

spec/support/templates/post_poro_decorator.rb

@@ -0,0 +1,23 @@
+class PostPoroDecorator
+  delegate_missing_to :post
+
+  def initialize(post)
+    @post = post
+  end
+
+  def self.decorate(record, *_)
+    if record.is_a?(Enumerable)
+      record.map { |individual_record| new(individual_record) }
+    else
+      new(record)
+    end
+  end
+
+  def decorator_method
+    'A method only available on the PORO decorator'
+  end
+
+  private
+
+  attr_reader :post
+end

spec/unit/resource_controller/decorators_spec.rb

@@ -8,9 +8,18 @@
 
     context "in show action" do
       let(:action) { 'show' }
-      let(:decorator_class) { PostDecorator }
 
-      it { is_expected.to be_kind_of(PostDecorator) }
+      context 'with a Draper decorator' do
+        let(:decorator_class) { PostDecorator }
+
+        it { is_expected.to be_kind_of(PostDecorator) }
+      end
+
+      context 'with a PORO decorator' do
+        let(:decorator_class) { PostPoroDecorator }
+
+        it { is_expected.to be_kind_of(PostPoroDecorator) }
+      end
     end
 
     context "in update action" do
@@ -54,8 +63,15 @@
     end
 
     context 'when the form is configured to decorate' do
-      let(:decorator_class) { PostDecorator }
-      it { is_expected.to be_kind_of(PostDecorator) }
+      context 'with a Draper decorator' do
+        let(:decorator_class) { PostDecorator }
+        it { is_expected.to be_kind_of(PostDecorator) }
+      end
+
+      context 'with a PORO decorator' do
+        let(:decorator_class) { PostPoroDecorator }
+        it { is_expected.to be_kind_of(PostPoroDecorator) }
+      end
     end
   end
 end

spec/unit/resource_controller_spec.rb

@@ -183,13 +183,29 @@ def call_after_destroy(obj); end
 
     context 'with a decorator' do
       let(:config) { controller.class.active_admin_config }
-      before { config.decorator_class_name = '::PostDecorator' }
-      it 'returns a PostDecorator' do
-        expect(subject).to be_kind_of(PostDecorator)
+
+      context 'with a Draper decorator' do
+        before { config.decorator_class_name = '::PostDecorator' }
+
+        it 'returns a PostDecorator' do
+          expect(subject).to be_kind_of(PostDecorator)
+        end
+
+        it 'returns a PostDecorator that wraps the post' do
+          expect(subject.title).to eq post.title
+        end
       end
 
-      it 'returns a PostDecorator that wraps the post' do
-        expect(subject.title).to eq post.title
+      context 'with a PORO decorator' do
+        before { config.decorator_class_name = '::PostPoroDecorator' }
+
+        it 'returns a PostDecorator' do
+          expect(subject).to be_kind_of(PostPoroDecorator)
+        end
+
+        it 'returns a PostDecorator that wraps the post' do
+          expect(subject.title).to eq post.title
+        end
       end
     end
   end
@@ -213,19 +229,6 @@ def call_after_destroy(obj); end
     it "returns a collection of posts" do
       expect(subject.first).to be_kind_of(Post)
     end
-
-    context 'with a decorator' do
-      before { config.decorator_class_name = 'PostDecorator' }
-
-      it 'returns a collection decorator using PostDecorator' do
-        expect(subject).to be_a Draper::CollectionDecorator
-        expect(subject.decorator_class).to eq PostDecorator
-      end
-
-      it 'returns a collection decorator that wraps the post' do
-        expect(subject.first.title).to eq Post.first.title
-      end
-    end
   end
 
   describe "performing batch_action" do