refactored AR attribute methods to define read method for all date, time and datetime attributes. Makes things much clearer and fixes bug reported (#2) by Brad (pvjg)

lib/validates_timeliness/active_record/attribute_methods.rb

@@ -14,24 +14,10 @@ module ValidatesTimeliness
     # will not be in the attribute cache on first read so will be considered in default
     # timezone and converted to local time. It is then stored back in the attributes
     # hash and cached to avoid the need for any subsequent differentiation.
-    #
-    # The wholesale replacement of the Rails time type casting is not done to
-    # preserve the quickest conversion for timestamp columns and also any value
-    # which is never changed during the life of the record object.
     module AttributeMethods
 
       def self.included(base)
         base.extend ClassMethods
-
-        if Rails::VERSION::STRING < '2.1'
-          base.class_eval do
-            class << self
-              def create_time_zone_conversion_attribute?(name, column)
-                false
-              end
-            end
-          end
-        end
       end
 
       # Adds check for cached date/time attributes which have been type cast already
@@ -57,25 +43,19 @@ module ValidatesTimeliness
         end
       end
 
-      # Writes attribute value by storing raw value in attributes hash,
-      # then convert it with parser and cache it.
-      #
       # If Rails dirty attributes is enabled then the value is added to
       # changed attributes if changed. Can't use the default dirty checking
       # implementation as it chains the write_attribute method which deletes
       # the attribute from the cache.
-      def write_date_time_attribute(attr_name, value)
-        column = column_for_attribute(attr_name)
+      def write_date_time_attribute(attr_name, value, type, time_zone_aware)
         old = read_attribute(attr_name) if defined?(::ActiveRecord::Dirty)
-        new = self.class.parse_date_time(value, column.type)
+        new = self.class.parse_date_time(value, type)
 
-        unless column.type == :date || new.nil?
+        unless type == :date || new.nil?
           new = new.to_time rescue new
         end
 
-        if self.class.send(:create_time_zone_conversion_attribute?, attr_name, column)
-          new = new.in_time_zone rescue nil
-        end
+        new = new.in_time_zone if new && time_zone_aware
         @attributes_cache[attr_name] = new
 
         if defined?(::ActiveRecord::Dirty) && !changed_attributes.include?(attr_name) && old != new
@@ -84,6 +64,24 @@ module ValidatesTimeliness
         @attributes[attr_name] = value
       end
 
+      # If reloading then check if cached, which means its in local time.
+      # If local, convert with parser as local timezone, otherwise use 
+      # read_attribute method for quick default type cast of values from
+      # database using default timezone.
+      def read_date_time_attribute(attr_name, type, time_zone_aware, reload = false)
+        cached = @attributes_cache[attr_name]
+        return cached if @attributes_cache.has_key?(attr_name) && !reload
+
+        if @attributes_cache.has_key?(attr_name)
+          time = read_attribute_before_type_cast(attr_name)
+          time = self.class.parse_date_time(date, type)
+        else
+          time = read_attribute(attr_name)
+          @attributes[attr_name] = time && time_zone_aware ? time.in_time_zone : time
+        end
+        @attributes_cache[attr_name] = time && time_zone_aware ? time.in_time_zone : time
+      end
+
       module ClassMethods
 
         # Override AR method to define attribute reader and writer method for
@@ -94,8 +92,9 @@ module ValidatesTimeliness
             unless instance_method_already_implemented?(name)
               if self.serialized_attributes[name]
                 define_read_method_for_serialized_attribute(name)
-              elsif create_time_zone_conversion_attribute?(name, column)
-                define_read_method_for_time_zone_conversion(name)
+              elsif [:date, :time, :datetime].include?(column.type)
+                time_zone_aware = create_time_zone_conversion_attribute?(name, column) rescue false
+                define_read_method_for_dates_and_times(name, column.type, time_zone_aware)
               else
                 define_read_method(name.to_sym, name, column)
               end
@@ -103,7 +102,8 @@ module ValidatesTimeliness
 
             unless instance_method_already_implemented?("#{name}=")
               if [:date, :time, :datetime].include?(column.type)
-                define_write_method_for_dates_and_times(name)
+                time_zone_aware = create_time_zone_conversion_attribute?(name, column) rescue false
+                define_write_method_for_dates_and_times(name, column.type, time_zone_aware)
               else
                 define_write_method(name.to_sym)
               end
@@ -116,32 +116,19 @@ module ValidatesTimeliness
         end
 
         # Define write method for date, time and datetime columns
-        def define_write_method_for_dates_and_times(attr_name)
+        def define_write_method_for_dates_and_times(attr_name, type, time_zone_aware)
           method_body = <<-EOV
             def #{attr_name}=(value)
-               write_date_time_attribute('#{attr_name}', value)
+               write_date_time_attribute('#{attr_name}', value, #{type.inspect}, #{time_zone_aware})
             end
           EOV
           evaluate_attribute_method attr_name, method_body, "#{attr_name}="
         end
 
-        # Define time attribute reader. If reloading then check if cached,
-        # which means its in local time. If local, convert with parser as local
-        # timezone, otherwise use read_attribute method for quick default type
-        # cast of values from database using default timezone.
-        def define_read_method_for_time_zone_conversion(attr_name)
+        def define_read_method_for_dates_and_times(attr_name, type, time_zone_aware)
           method_body = <<-EOV
             def #{attr_name}(reload = false)
-              cached = @attributes_cache['#{attr_name}']
-              return cached if @attributes_cache.has_key?('#{attr_name}') && !reload
-              if @attributes_cache.has_key?('#{attr_name}')
-                time = read_attribute_before_type_cast('#{attr_name}')
-                time = self.class.parse_date_time(date, :datetime)
-              else
-                time = read_attribute('#{attr_name}')
-                @attributes['#{attr_name}'] = time.in_time_zone rescue nil
-              end
-              @attributes_cache['#{attr_name}'] = time.in_time_zone rescue nil
+              read_date_time_attribute('#{attr_name}', #{type.inspect}, #{time_zone_aware}, reload)
             end
           EOV
           evaluate_attribute_method attr_name, method_body

spec/active_record/attribute_methods_spec.rb

@@ -23,6 +23,24 @@ describe ValidatesTimeliness::ActiveRecord::AttributeMethods do
     @person.birth_date_and_time = "2000-01-01 12:00"
   end
 
+  it "should call read_date_time_attribute when date attribute is retrieved" do
+    @person.should_receive(:read_date_time_attribute)
+    @person.birth_date = "2000-01-01"
+    @person.birth_date
+  end
+
+  it "should call read_date_time_attribute when time attribute is retrieved" do
+    @person.should_receive(:read_date_time_attribute)
+    @person.birth_time = "12:00"
+    @person.birth_time
+  end
+
+  it "should call rea_date_time_attribute when datetime attribute is retrieved" do
+    @person.should_receive(:read_date_time_attribute)
+    @person.birth_date_and_time = "2000-01-01 12:00"
+    @person.birth_date_and_time
+  end
+
   it "should call parser on write for datetime attribute" do
     @person.class.should_receive(:parse_date_time).once
     @person.birth_date_and_time = "2000-01-01 02:03:04"