Allow sweepers to be created solely for expiring after controller actions, not model changes [DHH] Added assigns method to ActionController::Caching::Sweeper to easily access instance variables on the controller [DHH]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@7128 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

3 files changed, 16 insertions, 3 deletions

diff --git a/actionpack/CHANGELOG b/actionpack/CHANGELOG
index 3fd9a7dba8..9001ffb7fb 100644
--- a/actionpack/CHANGELOG
+++ b/actionpack/CHANGELOG
@@ -1,5 +1,9 @@
 *SVN*
 
+* Allow sweepers to be created solely for expiring after controller actions, not model changes [DHH]
+
+* Added assigns method to ActionController::Caching::Sweeper to easily access instance variables on the controller [DHH]
+
 * Give the legacy X-POST_DATA_FORMAT header greater precedence during params parsing for backward compatibility.  [Jeremy Kemper]
 
 * Fixed that link_to with an href of # when using :method will not allow for click-through without JavaScript #7037 [stevenbristol/josh]
diff --git a/actionpack/lib/action_controller/caching.rb b/actionpack/lib/action_controller/caching.rb
index f9f3c37c1c..75aa9df812 100644
--- a/actionpack/lib/action_controller/caching.rb
+++ b/actionpack/lib/action_controller/caching.rb
@@ -636,6 +636,11 @@ module ActionController #:nodoc:
             ActionController::Caching::Actions::ActionCachePath.path_for(controller, options)
           end
 
+          # Retrieve instance variables set in the controller.
+          def assigns(key)
+            controller.instance_variable_get("@#{key}")
+          end
+
         private
           def callback(timing)
             controller_callback_method_name = "#{timing}_#{controller.controller_name.underscore}"
diff --git a/activerecord/lib/active_record/observer.rb b/activerecord/lib/active_record/observer.rb
index ace52ef415..29edabc9b1 100644
--- a/activerecord/lib/active_record/observer.rb
+++ b/activerecord/lib/active_record/observer.rb
@@ -140,7 +140,11 @@ module ActiveRecord
       # The class observed by default is inferred from the observer's class name:
       #   assert_equal [Person], PersonObserver.observed_class
       def observed_class
-        name.scan(/(.*)Observer/)[0][0].constantize
+        if observed_class_name = name.scan(/(.*)Observer/)[0]
+          observed_class_name[0].constantize
+        else
+          nil
+        end
       end
     end
 
@@ -163,11 +167,11 @@ module ActiveRecord
 
     protected
       def observed_classes
-        Set.new([self.class.observed_class].flatten)
+        Set.new([self.class.observed_class].compact.flatten)
       end
 
       def observed_subclasses
-        observed_classes.sum(&:subclasses)
+        observed_classes.collect(&:subclasses).flatten
       end
 
       def add_observer!(klass)