module ActiveRecord::AttributeMethods::Serialization::ClassMethods - activerecord-4.2.4 Documentation

# module ActiveRecord::AttributeMethods::Serialization::ClassMethods

### Public Instance Methods

serialize(attr_name, class_name_or_coder = Object) click to toggle source

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 assignment and retrieval. Otherwise `SerializationTypeMismatch` will be raised.

#### Parameters¶ ↑

- `attr_name` - The field name that should be serialized.

- `class_name_or_coder` - Optional, a coder object, which responds to `.load` / `.dump` or a class name that the object type should be equal to.

#### Example¶ ↑

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

    # Serialize preferences using JSON as coder.
    class User < ActiveRecord::Base
      serialize :preferences, JSON
    end

    # Serialize preferences as Hash using YAML coder.
    class User < ActiveRecord::Base
      serialize :preferences, Hash
    end

    # File lib/active_record/attribute_methods/serialization.rb, line 38
    def serialize(attr_name, class_name_or_coder = Object)
      # When ::JSON is used, force it to go through the Active Support JSON encoder
      # to ensure special objects (e.g. Active Record models) are dumped correctly
      # using the #as_json hook.
      coder = if class_name_or_coder == ::JSON
                Coders::JSON
              elsif [:load, :dump].all? { |x| class_name_or_coder.respond_to?(x) }
                class_name_or_coder
              else
                Coders::YAMLColumn.new(class_name_or_coder)
              end

      decorate_attribute_type(attr_name, :serialize) do |type|
        Type::Serialized.new(type, coder)
      end
    end

serialized_attributes() click to toggle source

    # File lib/active_record/attribute_methods/serialization.rb, line 55
            def serialized_attributes
              ActiveSupport::Deprecation.warn("            `serialized_attributes` is deprecated without replacement, and will
                be removed in Rails 5.0.
    ".squish)

              @serialized_attributes ||= Hash[
                columns.select { |t| t.cast_type.is_a?(Type::Serialized) }.map { |c|
                  [c.name, c.cast_type.coder]
                }
              ]
            end