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Active Model Serialization

為您的物件提供基本序列化至 serializable_hash。

最小實作可以是

class Person
  include ActiveModel::Serialization

  attr_accessor :name

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

將提供您

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

必須定義 attributes hash，且應包含您需要序列化的任何屬性。 Attributes 必須是字串，而非符號。呼叫時，可序列化 hash 將使用與屬性 hash 的金鑰名稱相符的實例方法。若要覆寫此行為，請查看私有方法 read_attribute_for_serialization。

ActiveModel::Serializers::JSON 模組會自動包含 ActiveModel::Serialization 模組，因此不需要明確包含 ActiveModel::Serialization。

包含 JSON 的最小實作可以是

class Person
  include ActiveModel::Serializers::JSON

  attr_accessor :name

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

將提供您

person = Person.new
person.serializable_hash   # => {"name"=>nil}
person.as_json             # => {"name"=>nil}
person.to_json             # => "{\"name\":null}"

person.name = "Bob"
person.serializable_hash   # => {"name"=>"Bob"}
person.as_json             # => {"name"=>"Bob"}
person.to_json             # => "{\"name\":\"Bob\"}"

有效的選項為 :only、:except、:methods 和 :include。以下是所有有效範例

person.serializable_hash(only: 'name')
person.serializable_hash(include: :address)
person.serializable_hash(include: { address: { only: 'city' }})
方法
S

實例公開方法

serializable_hash(options = nil)

傳回您物件的序列化 hash。

class Person
  include ActiveModel::Serialization

  attr_accessor :name, :age

  def attributes
    {'name' => nil, 'age' => nil}
  end

  def capitalized_name
    name.capitalize
  end
end

person = Person.new
person.name = 'bob'
person.age  = 22
person.serializable_hash                # => {"name"=>"bob", "age"=>22}
person.serializable_hash(only: :name)   # => {"name"=>"bob"}
person.serializable_hash(except: :name) # => {"age"=>22}
person.serializable_hash(methods: :capitalized_name)
# => {"name"=>"bob", "age"=>22, "capitalized_name"=>"Bob"}

使用 :include 選項的範例

class User
  include ActiveModel::Serializers::JSON
  attr_accessor :name, :notes # Emulate has_many :notes
  def attributes
    {'name' => nil}
  end
end

class Note
  include ActiveModel::Serializers::JSON
  attr_accessor :title, :text
  def attributes
    {'title' => nil, 'text' => nil}
  end
end

note = Note.new
note.title = 'Battle of Austerlitz'
note.text = 'Some text here'

user = User.new
user.name = 'Napoleon'
user.notes = [note]

user.serializable_hash
# => {"name" => "Napoleon"}
user.serializable_hash(include: { notes: { only: 'title' }})
# => {"name" => "Napoleon", "notes" => [{"title"=>"Battle of Austerlitz"}]}

來源：顯示 | 在 GitHub 上 

# File activemodel/lib/active_model/serialization.rb, line 125
def serializable_hash(options = nil)
  attribute_names = attribute_names_for_serialization

  return serializable_attributes(attribute_names) if options.blank?

  if only = options[:only]
    attribute_names &= Array(only).map(&:to_s)
  elsif except = options[:except]
    attribute_names -= Array(except).map(&:to_s)
  end

  hash = serializable_attributes(attribute_names)

  Array(options[:methods]).each { |m| hash[m.to_s] = send(m) }

  serializable_add_includes(options) do |association, records, opts|
    hash[association.to_s] = if records.respond_to?(:to_ary)
      records.to_ary.map { |a| a.serializable_hash(opts) }
    else
      records.serializable_hash(opts)
    end
  end

  hash
end