Extract archive rendering related controller code

In admin attachments and admin elements controllers we use the
same code to handle the archive rendering. Either in an overlay
dialog (if a content_id is available) or as normal html index view.

app/controllers/alchemy/admin/attachments_controller.rb

@@ -4,6 +4,7 @@ module Alchemy
   module Admin
     class AttachmentsController < ResourcesController
       include UploaderResponses
+      include ArchiveOverlay
 
       helper 'alchemy/admin/tags'
 
@@ -85,18 +86,6 @@ def handle_uploader_response(status:)
         end
       end
 
-      def in_overlay?
-        params[:content_id].present?
-      end
-
-      def archive_overlay
-        @content = Content.find_by(id: params[:content_id])
-        respond_to do |format|
-          format.html { render partial: 'archive_overlay' }
-          format.js   { render action:  'archive_overlay' }
-        end
-      end
-
       def attachment_attributes
         params.require(:attachment).permit(:file, :name, :file_name, :tag_list)
       end

app/controllers/alchemy/admin/pictures_controller.rb

@@ -4,6 +4,7 @@ module Alchemy
   module Admin
     class PicturesController < Alchemy::Admin::ResourcesController
       include UploaderResponses
+      include ArchiveOverlay
 
       helper 'alchemy/admin/tags'
 
@@ -143,19 +144,6 @@ def pictures_per_page_for_size(size)
         end
       end
 
-      def in_overlay?
-        params[:content_id].present?
-      end
-
-      def archive_overlay
-        @content = Content.find_by(id: params[:content_id])
-
-        respond_to do |format|
-          format.html { render partial: 'archive_overlay' }
-          format.js   { render action:  'archive_overlay' }
-        end
-      end
-
       def redirect_to_index
         do_redirect_to admin_pictures_path(search_filter_params)
       end

app/controllers/concerns/alchemy/admin/archive_overlay.rb

@@ -0,0 +1,20 @@
+module Alchemy
+  module Admin
+    module ArchiveOverlay
+      private
+
+      def in_overlay?
+        params[:content_id].present?
+      end
+
+      def archive_overlay
+        @content = Content.find_by(id: params[:content_id])
+
+        respond_to do |format|
+          format.html { render partial: 'archive_overlay' }
+          format.js   { render action:  'archive_overlay' }
+        end
+      end
+    end
+  end
+end

spec/controllers/alchemy/admin/pictures_controller_spec.rb

@@ -365,7 +365,7 @@ module Alchemy
       end
 
       context 'in overlay' do
-        let(:params) { {element_id: :id, size: size} }
+        let(:params) { {content_id: :id, size: size} }
 
         context 'with params[:size] set to medium' do
           let(:size) { 'medium' }