require 'active_support/core_ext/hash/except' require 'active_support/core_ext/hash/slice' require 'active_support/core_ext/array/wrap' module ActiveModel # == 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 # {'name' => name} # 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 # {'name' => name} # 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 # => "\n {"name"=>"Bob"} # person.as_json # => {"name"=>"Bob"} # person.to_json # => "{\"name\":\"Bob\"}" # person.to_xml # => "\n:only, :except and :methods . module Serialization def serializable_hash(options = nil) options ||= {} attribute_names = attributes.keys.sort if only = options[:only] attribute_names &= Array.wrap(only).map(&:to_s) elsif except = options[:except] attribute_names -= Array.wrap(except).map(&:to_s) end hash = {} attribute_names.each { |n| hash[n] = read_attribute_for_serialization(n) } method_names = Array.wrap(options[:methods]).select { |n| respond_to?(n) } method_names.each { |n| hash[n] = send(n) } serializable_add_includes(options) do |association, records, opts| hash[association] = if records.is_a?(Enumerable) records.map { |a| a.serializable_hash(opts) } else records.serializable_hash(opts) end end hash end private # Hook method defining how an attribute value should be retrieved for # serialization. By default this is assumed to be an instance named after # the attribute. Override this method in subclasses should you need to # retrieve the value for a given attribute differently: # # class MyClass # include ActiveModel::Validations # # def initialize(data = {}) # @data = data # end # # def read_attribute_for_serialization(key) # @data[key] # end # end # alias :read_attribute_for_serialization :send # Add associations specified via the :include option. # # Expects a block that takes as arguments: # +association+ - name of the association # +records+ - the association record(s) to be serialized # +opts+ - options for the association records def serializable_add_includes(options = {}) #:nodoc: return unless include = options[:include] unless include.is_a?(Hash) include = Hash[Array.wrap(include).map { |n| [n, {}] }] end include.each do |association, opts| if records = send(association) yield association, records, opts end end end end end