Concernify AR AttributeMethods

1 files changed, 60 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
new file mode 100644
index 0000000000..f379b4c0f8
--- /dev/null
+++ b/activerecord/lib/active_record/attribute_methods/time_zone_conversion.rb
@@ -0,0 +1,60 @@
+module ActiveRecord
+  module AttributeMethods
+    module TimeZoneConversion
+      extend ActiveSupport::Concern
+
+      included do
+        cattr_accessor :time_zone_aware_attributes, :instance_writer => false
+        self.time_zone_aware_attributes = false
+
+        class_inheritable_accessor :skip_time_zone_conversion_for_attributes, :instance_writer => false
+        self.skip_time_zone_conversion_for_attributes = []
+      end
+
+      module ClassMethods
+        protected
+          # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+          # This enhanced read method automatically converts the UTC time stored in the database to the time zone stored in Time.zone.
+          def define_attribute_method(attr_name)
+            if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
+              method_body = <<-EOV
+                def #{attr_name}(reload = false)
+                  cached = @attributes_cache['#{attr_name}']
+                  return cached if cached && !reload
+                  time = read_attribute('#{attr_name}')
+                  @attributes_cache['#{attr_name}'] = time.acts_like?(:time) ? time.in_time_zone : time
+                end
+              EOV
+              evaluate_attribute_method attr_name, method_body, attr_name
+            else
+              super
+            end
+          end
+
+          # Defined for all +datetime+ and +timestamp+ attributes when +time_zone_aware_attributes+ are enabled.
+          # This enhanced write method will automatically convert the time passed to it to the zone stored in Time.zone.
+          def define_attribute_method=(attr_name)
+            if create_time_zone_conversion_attribute?(attr_name, columns_hash[attr_name])
+              method_body = <<-EOV
+                def #{attr_name}=(time)
+                  unless time.acts_like?(:time)
+                    time = time.is_a?(String) ? Time.zone.parse(time) : time.to_time rescue time
+                  end
+                  time = time.in_time_zone rescue nil if time
+                  write_attribute(:#{attr_name}, time)
+                end
+              EOV
+              evaluate_attribute_method attr_name, method_body, "#{attr_name}="
+            else
+              super
+            end
+          end
+
+        private
+          def create_time_zone_conversion_attribute?(name, column)
+            time_zone_aware_attributes && !skip_time_zone_conversion_for_attributes.include?(name.to_sym) && [:datetime, :timestamp].include?(column.type)
+          end
+      end
+    end
+  end
+end