Module | ActiveRecord::AttributeMethods::Read::ClassMethods |
In: |
lib/active_record/attribute_methods/read.rb
|
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).
Returns the attributes which are cached. By default time related columns with datatype :datetime, :timestamp, :time, :date are cached.
We want to generate the methods via module_eval rather than define_method, because define_method is slower on dispatch and uses more memory (because it creates a closure).
But sometimes the database might return columns with characters that are not allowed in normal method names (like ‘my_column(omg)’. So to work around this we first define with the temp identifier, and then use alias method to rename it to what we want.