Module: ActiveRecord::AttributeMethods::Serialization::ClassMethods

Defined in:
activerecord/lib/active_record/attribute_methods/serialization.rb

Instance Method Summary collapse

Instance Method Details

#serialize(attr_name, class_name = Object) ⇒ Object

If you have an attribute that needs to be saved to the database as an object, and retrieved as the same object, then specify the name of that attribute using this method and it will be handled automatically. The serialization is done through YAML. If class_name is specified, the serialized object must be of that class on retrieval or SerializationTypeMismatch will be raised.

Parameters

  • attr_name - The field name that should be serialized.

  • class_name - Optional, class name that the object type should be equal to.

Example

# Serialize a preferences attribute.
class User < ActiveRecord::Base
  serialize :preferences
end

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# File 'activerecord/lib/active_record/attribute_methods/serialization.rb', line 38

def serialize(attr_name, class_name = Object)
  include Behavior

  coder = if [:load, :dump].all? { |x| class_name.respond_to?(x) }
            class_name
          else
            Coders::YAMLColumn.new(class_name)
          end

  # merge new serialized attribute and create new hash to ensure that each class in inheritance hierarchy
  # has its own hash of own serialized attributes
  self.serialized_attributes = serialized_attributes.merge(attr_name.to_s => coder)
end