Decorate associations of a decorated object

lib/active_decorator/decorator.rb

@@ -28,8 +28,19 @@ def to_a_with_decorator
       else
         d = decorator_for obj.class
         return obj unless d
-        obj.extend d unless obj.is_a? d
+        unless obj.is_a? d
+          obj.extend d
+          (class << obj ; self ; end).class_eval do
+            obj.class.reflect_on_all_associations.map(&:name).each do |assoc|
+              define_method(assoc) { |*args|
+                associated = super(*args)
+                Decorator.instance.decorate(associated)
+              }
+            end
+          end if obj.class.respond_to? :reflect_on_all_associations
+        end
       end
+      obj
     end
 
     private

spec/fake_app/books/show.html.erb

@@ -1,2 +1,3 @@
 <%= @book.link %>
 <%= @book.cover_image %>
+<%= @book.attribution %>

spec/fake_app/fake_app.rb

@@ -58,6 +58,10 @@ def link
   def cover_image
     image_tag 'cover.png'
   end
+
+  def attribution
+    "#{title}, by #{author.capitalized_name}"
+  end
 end
 
 # controllers

spec/requests/action_view_helpers_spec.rb

@@ -12,5 +12,6 @@
       page.should have_content 'RHG'
     end
     page.should have_css('img')
+    page.should have_content 'RHG, by Aamine'
   end
 end