Active Model Serialization

Provides a basic serialization to a serializable_hash for your object.

A minimal implementation could be:

  class Person

    include ActiveModel::Serialization

    attr_accessor :name

    def attributes
      @attributes ||= {'name' => 'nil'}
    end

  end

Which would provide you with:

  person = Person.new
  person.serializable_hash   # => {"name"=>nil}
  person.name = "Bob"
  person.serializable_hash   # => {"name"=>"Bob"}

You need to declare some sort of attributes hash which contains the attributes you want to serialize and their current value.

Most of the time though, you will want to include the JSON or XML serializations. Both of these modules automatically include the ActiveModel::Serialization module, so there is no need to explicitly include it.

So a minimal implementation including XML and JSON would be:

  class Person

    include ActiveModel::Serializers::JSON
    include ActiveModel::Serializers::Xml

    attr_accessor :name

    def attributes
      @attributes ||= {'name' => 'nil'}
    end

  end

Which would provide you with:

  person = Person.new
  person.serializable_hash   # => {"name"=>nil}
  person.as_json             # => {"name"=>nil}
  person.to_json             # => "{\"name\":null}"
  person.to_xml              # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...

  person.name = "Bob"
  person.serializable_hash   # => {"name"=>"Bob"}
  person.as_json             # => {"name"=>"Bob"}
  person.to_json             # => "{\"name\":\"Bob\"}"
  person.to_xml              # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...

Valid options are :only, :except and :methods .

    # File lib/active_model/serialization.rb, line 69
69:     def serializable_hash(options = nil)
70:       options ||= {}
71: 
72:       only   = Array.wrap(options[:only]).map(&:to_s)
73:       except = Array.wrap(options[:except]).map(&:to_s)
74: 
75:       attribute_names = attributes.keys.sort
76:       if only.any?
77:         attribute_names &= only
78:       elsif except.any?
79:         attribute_names -= except
80:       end
81: 
82:       method_names = Array.wrap(options[:methods]).inject([]) do |methods, name|
83:         methods << name if respond_to?(name.to_s)
84:         methods
85:       end
86: 
87:       (attribute_names + method_names).inject({}) { |hash, name|
88:         hash[name] = send(name)
89:         hash
90:       }
91:     end