Added ActiveRecord::Base#touch to update the updated_at/on attributes with the current time [DHH]

activerecord/CHANGELOG

+*Edge*
+
+* Added ActiveRecord::Base#touch to update the updated_at/on attributes with the current time [DHH]
+
+
 *2.3.2 [Final] (March 15, 2009)*
 
 * Added ActiveRecord::Base.find_each and ActiveRecord::Base.find_in_batches for batch processing [DHH/Jamis Buck]

activerecord/lib/active_record/timestamp.rb

@@ -15,27 +15,47 @@ def self.included(base) #:nodoc:
       base.class_inheritable_accessor :record_timestamps, :instance_writer => false
       base.record_timestamps = true
     end
+    
+    # Saves the record with the updated_at/on attributes set to the current time.
+    # If the save fails because of validation errors, an ActiveRecord::RecordInvalid exception is raised.
+    def touch
+      current_time = current_time_from_proper_timezone
+
+      write_attribute('updated_at', current_time) if respond_to?(:updated_at)
+      write_attribute('updated_on', current_time) if respond_to?(:updated_on)
+
+      save!
+    end
+
 
     private
       def create_with_timestamps #:nodoc:
         if record_timestamps
-          t = self.class.default_timezone == :utc ? Time.now.utc : Time.now
-          write_attribute('created_at', t) if respond_to?(:created_at) && created_at.nil?
-          write_attribute('created_on', t) if respond_to?(:created_on) && created_on.nil?
+          current_time = current_time_from_proper_timezone
+
+          write_attribute('created_at', current_time) if respond_to?(:created_at) && created_at.nil?
+          write_attribute('created_on', current_time) if respond_to?(:created_on) && created_on.nil?
 
-          write_attribute('updated_at', t) if respond_to?(:updated_at) && updated_at.nil?
-          write_attribute('updated_on', t) if respond_to?(:updated_on) && updated_on.nil?
+          write_attribute('updated_at', current_time) if respond_to?(:updated_at) && updated_at.nil?
+          write_attribute('updated_on', current_time) if respond_to?(:updated_on) && updated_on.nil?
         end
+
         create_without_timestamps
       end
 
       def update_with_timestamps(*args) #:nodoc:
         if record_timestamps && (!partial_updates? || changed?)
-          t = self.class.default_timezone == :utc ? Time.now.utc : Time.now
-          write_attribute('updated_at', t) if respond_to?(:updated_at)
-          write_attribute('updated_on', t) if respond_to?(:updated_on)
+          current_time = current_time_from_proper_timezone
+
+          write_attribute('updated_at', current_time) if respond_to?(:updated_at)
+          write_attribute('updated_on', current_time) if respond_to?(:updated_on)
         end
+
         update_without_timestamps(*args)
       end
+      
+      def current_time_from_proper_timezone
+        self.class.default_timezone == :utc ? Time.now.utc : Time.now
+      end
   end
-end
+end
\ No newline at end of file

activerecord/test/cases/timestamp_test.rb

+require 'cases/helper'
+require 'models/developer'
+
+class TimestampTest < ActiveRecord::TestCase
+  fixtures :developers
+
+  def setup
+    @developer = Developer.first
+    @previously_updated_at = @developer.updated_at
+  end
+
+  def test_saving_a_changed_record_updates_its_timestamp
+    @developer.name = "Jack Bauer"
+    @developer.save!
+    
+    assert @previously_updated_at != @developer.updated_at
+  end
+  
+  def test_saving_a_unchanged_record_doesnt_update_its_timestamp
+    @developer.save!
+    
+    assert @previously_updated_at == @developer.updated_at
+  end
+  
+  def test_touching_a_record_updates_its_timestamp
+    @developer.touch
+    
+    assert @previously_updated_at != @developer.updated_at
+  end
+end
\ No newline at end of file