serialize(attr_name, class_name_or_coder = Object) public

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
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September 11, 2012 - (>= v3.1.0)
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Custom serialization

It is possible to supply a class with own (de)serialization logic to the serialize call. Given object must respond to load and dump calls.

Following example serializes symbols into their string representation and store them in database as raw strings instead of their YAML representation, i.e. :pumpkin would be stored as ‘pumpkin’, and not as ‘--- :pumpkin\n’

Example

clas SomeModel < ActiveRecord::Base
  class SymbolWrapper
    def self.load(string)
      string.to_sym
    end

    def self.dump(symbol)
      symbol.to_s
    end
  end

  serialize :value, SymbolWrapper
end