Added ActiveRecord::Mixins::Touch that will record creation and update times of objects [xal]

git-svn-id: http://svn-commit.rubyonrails.org/rails/trunk@85 5ecf4fe2-1ee6-0310-87b1-e25e094e27de

1 files changed, 35 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/mixins/touch.rb b/activerecord/lib/active_record/mixins/touch.rb
new file mode 100644
index 0000000000..74a1737cab
--- /dev/null
+++ b/activerecord/lib/active_record/mixins/touch.rb
@@ -0,0 +1,35 @@
+module ActiveRecord
+  module Mixins
+    # Including this mixins will record when objects of the class are created in a datetime column called "created_at"
+    # and when its updated in another datetime column called "updated_at".
+    #
+    #   class Bill < ActiveRecord::Base
+    #     include ActiveRecord::Mixins::Touch
+    #   end
+    #
+    #   bill = Bill.create("amount" => 100)
+    #   bill.created_at # => Time.now at the moment of Bill.create
+    #   bill.updated_at # => Time.now at the moment of Bill.create
+    #
+    #   bill.update_attribute("amount", 150)
+    #   bill.created_at # => Time.now at the moment of Bill.create
+    #   bill.updated_at # => Time.now at the moment of bill.update_attribute
+    module Touch
+      def self.append_features(base)
+        super
+        base.class_eval do
+          before_create :touch_on_create
+          before_update :touch_on_update
+
+          def touch_on_create
+            self.created_at = self.updated_at = Time.now
+          end
+
+          def touch_on_update
+            self.updated_at = Time.now
+          end
+        end
+      end  
+    end
+  end
+end
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