Returns true if the provided attribute is being cached.
# File lib/active_record/attribute_methods/read.rb, line 34 34: def cache_attribute?(attr_name) 35: cached_attributes.include?(attr_name) 36: end
cache_attributes allows you to declare which converted attribute values should be cached. Usually caching only pays off for attributes with expensive conversion methods, like time related columns (e.g. created_at, updated_at).
# File lib/active_record/attribute_methods/read.rb, line 22 22: def cache_attributes(*attribute_names) 23: attribute_names.each {|attr| cached_attributes << attr.to_s} 24: end
Returns the attributes which are cached. By default time related columns with datatype :datetime, :timestamp, :time, :date are cached.
# File lib/active_record/attribute_methods/read.rb, line 28 28: def cached_attributes 29: @cached_attributes ||= 30: columns.select{|c| attribute_types_cached_by_default.include?(c.type)}.map{|col| col.name}.to_set 31: end
# File lib/active_record/attribute_methods/read.rb, line 39 39: def define_method_attribute(attr_name) 40: if self.serialized_attributes[attr_name] 41: define_read_method_for_serialized_attribute(attr_name) 42: else 43: define_read_method(attr_name.to_sym, attr_name, columns_hash[attr_name]) 44: end 45: 46: if attr_name == primary_key && attr_name != "id" 47: define_read_method(:id, attr_name, columns_hash[attr_name]) 48: end 49: end
Define an attribute reader method. Cope with nil column.
# File lib/active_record/attribute_methods/read.rb, line 58 58: def define_read_method(symbol, attr_name, column) 59: cast_code = column.type_cast_code('v') if column 60: access_code = cast_code ? "(v=@attributes['#{attr_name}']) && #{cast_code}" : "@attributes['#{attr_name}']" 61: 62: unless attr_name.to_s == self.primary_key.to_s 63: access_code = access_code.insert(0, "missing_attribute('#{attr_name}', caller) unless @attributes.has_key?('#{attr_name}'); ") 64: end 65: 66: if cache_attribute?(attr_name) 67: access_code = "@attributes_cache['#{attr_name}'] ||= (#{access_code})" 68: end 69: generated_attribute_methods.module_eval("def #{symbol}; #{access_code}; end", __FILE__, __LINE__) 70: end
Define read method for serialized attribute.
# File lib/active_record/attribute_methods/read.rb, line 53 53: def define_read_method_for_serialized_attribute(attr_name) 54: generated_attribute_methods.module_eval("def #{attr_name}; unserialize_attribute('#{attr_name}'); end", __FILE__, __LINE__) 55: end
Disabled; run with --debug to generate this.
Generated with the Darkfish Rdoc Generator 1.1.6.