class ActiveModel::Serializer

end
end
post.author == scope
def author?
end
hash
hash.merge!(:email => post.email) if author?
hash = super
def attributes
private
has_many :comments
attributes :title, :body
class PostSerializer < ActiveModel::Serializer
author of the post:
For example, some attributes may only be returned if current_user is the
We use the scope to check if a given attribute should be serialized or not.
in for authorization purposes.
The object to be serialized is the +@post+ and the current user is passed
PostSerializer.new(@post, :scope => current_user).to_json
one may do in a controller:
it expects two objects as arguments, a resource and options. For example,
control how a given object is going to be serialized. On initialization,
Provides a basic serializer implementation that allows you to easily
Active Model Serializer

def _serializable_hash

def _serializable_hash
  return nil if @object.nil?
  @node = attributes
  include_associations! if _embed
  @node
end

def as_json(options={})

object including the root.
Returns a json representation of the serializable

def as_json(options={})
  if root = options.fetch(:root, @options.fetch(:root, root_name))
    @options[:hash] = hash = {}
    @options[:unique_values] = {}
    hash.merge!(root => serializable_hash)
    include_meta hash
    hash
  else
    serializable_hash
  end
end

def associate(klass, attrs) #:nodoc:

:nodoc:

def associate(klass, attrs) #:nodoc:
  options = attrs.extract_options!
  self._associations = _associations.dup
  attrs.each do |attr|
    unless method_defined?(attr)
      define_method attr do
        object.send attr
      end
    end
    define_include_method attr
    self._associations[attr] = klass.refine(attr, options)
  end
end

def attribute(attr, options={})

def attribute(attr, options={})
  self._attributes = _attributes.merge(attr.is_a?(Hash) ? attr : {attr => options[:key] || attr.to_s.gsub(/\?$/, '').to_sym})
  attr = attr.keys[0] if attr.is_a? Hash
  unless method_defined?(attr)
    define_method attr do
      object.read_attribute_for_serialization(attr.to_sym)
    end
  end
  define_include_method attr
  # protect inheritance chains and open classes
  # if a serializer inherits from another OR
  #  attributes are added later in a classes lifecycle
  # poison the cache
  define_method :_fast_attributes do
    raise NameError
  end
end

def attributes(*attrs)

Define attributes to be used in the serialization.

def attributes(*attrs)
  self._attributes = _attributes.dup
  attrs.each do |attr|
    if Hash === attr
      attr.each {|attr_real, key| attribute attr_real, :key => key }
    else
      attribute attr
    end
  end
end

def attributes

object attributes.
Returns a hash representation of the serializable

def attributes
  _fast_attributes
  rescue NameError
    method = "def _fast_attributes\n"
    method << "  h = {}\n"
    _attributes.each do |name,key|
      method << "  h[:\"#{key}\"] = read_attribute_for_serialization(:\"#{name}\") if include?(:\"#{name}\")\n"
    end
    method << "  h\nend"
    self.class.class_eval method
    _fast_attributes
end

def build_json(controller, resource, options)

not be manually defined for this method.
set during the request lifecycle or by the controller class, and should
settings and options for a given resource. These settings are typically
Used internally to create a new serializer object based on controller

def build_json(controller, resource, options)
  default_options = controller.send(:default_serializer_options) || {}
  options = default_options.merge(options || {})
  serializer = options.delete(:serializer) ||
    (resource.respond_to?(:active_model_serializer) &&
     resource.active_model_serializer)
  return serializer unless serializer
  if resource.respond_to?(:to_ary)
    unless serializer <= ActiveModel::ArraySerializer
      raise ArgumentError.new("#{serializer.name} is not an ArraySerializer. " +
                              "You may want to use the :each_serializer option instead.")
    end
    if options[:root] != false && serializer.root != false
      # the serializer for an Array is ActiveModel::ArraySerializer
      options[:root] ||= serializer.root || controller.controller_name
    end
  end
  options[:scope] = controller.serialization_scope unless options.has_key?(:scope)
  options[:scope_name] = controller._serialization_scope
  options[:url_options] = controller.url_options
  serializer.new(resource, options)
end

def cached(value = true)

set perform caching like root

def cached(value = true)
  self.perform_caching = value
end

def define_include_method(name)

def define_include_method(name)
  method = "include_#{name}?".to_sym
  INCLUDE_METHODS[name] = method
  unless method_defined?(method)
    define_method method do
      true
    end
  end
end

def embed(type, options={})

embed :ids, :include => true # Embed the association ids and include objects in the root
embed :ids # Embed only the association ids
embed :objects # Embed associations as full objects

Define how associations should be embedded.

def embed(type, options={})
  self._embed = type
  self._root_embed = true if options[:include]
end

def expand_cache_key(*args)

def expand_cache_key(*args)
  ActiveSupport::Cache.expand_cache_key(args)
end

def has_many(*attrs)

dispatched to the serialized object.
with the association name does not exist, the association name is
as a method which should return an array when invoked. If a method
The serializer object should implement the association name

Defines an association in the object should be rendered.

def has_many(*attrs)
  associate(Associations::HasMany, attrs)
end

def has_one(*attrs)

dispatched to the serialized object.
with the association name does not exist, the association name is
as a method which should return an object when invoked. If a method
The serializer object should implement the association name

Defines an association in the object should be rendered.

def has_one(*attrs)
  associate(Associations::HasOne, attrs)
end

def include!(name, options={})

def include!(name, options={})
  # Make sure that if a special options[:hash] was passed in, we generate
  # a new unique values hash and don't clobber the original. If the hash
  # passed in is the same as the current options hash, use the current
  # unique values.
  #
  # TODO: Should passing in a Hash even be public API here?
  unique_values =
    if hash = options[:hash]
      if @options[:hash] == hash
        @options[:unique_values] ||= {}
      else
        {}
      end
    else
      hash = @options[:hash]
      @options[:unique_values] ||= {}
    end
  node = options[:node] ||= @node
  value = options[:value]
  if options[:include] == nil
    if @options.key?(:include)
      options[:include] = @options[:include].include?(name)
    elsif @options.include?(:exclude)
      options[:include] = !@options[:exclude].include?(name)
    end
  end
  association_class =
    if klass = _associations[name]
      klass
    elsif value.respond_to?(:to_ary)
      Associations::HasMany
    else
      Associations::HasOne
    end
  association = association_class.new(name, self, options)
  if association.embed_ids?
    node[association.key] = association.serialize_ids
    if association.embed_in_root? && hash.nil?
      raise IncludeError.new(self.class, association.name)
    elsif association.embed_in_root? && association.embeddable?
      merge_association hash, association.root, association.serializables, unique_values
    end
  elsif association.embed_objects?
    node[association.key] = association.serialize
  end
end

def include?(name)

def include?(name)
  return false if options.key?(:only) && !Array(options[:only]).include?(name)
  return false if options.key?(:except) && Array(options[:except]).include?(name)
  send INCLUDE_METHODS[name]
end

def include_associations!

def include_associations!
  _associations.each_key do |name|
    include!(name) if include?(name)
  end
end

def include_meta(hash)

def include_meta(hash)
  hash[meta_key] = @options[:meta] if @options.has_key?(:meta)
end

def initialize(object, options={})

def initialize(object, options={})
  @object, @options = object, options
  scope_name = @options[:scope_name]
  if scope_name && !respond_to?(scope_name)
    self.class.class_eval do
      define_method scope_name, lambda { scope }
    end
  end
end

def instrument(name, payload = {}, &block)

The event name is: name.class_name.serializer
Use ActiveSupport::Notifications to send events to external systems.

def instrument(name, payload = {}, &block)
  event_name = INSTRUMENT[name]
  ActiveSupport::Notifications.instrument(event_name, payload, &block)
end

def merge_association(hash, key, serializables, unique_values)

we want to merge a new list of values.
avoids the need to scan through the Array looking for entries every time
a unique list of all of the objects that are already in the Array. This
In order to make this efficient, we store a :unique_values hash containing

of all tags for all comments of the post.
which has_many tags, the top-level :tags key will contain the merged list
content for all of the children. For instance, if a Post has_many comments,
In some cases, an Array of associations is built by merging the associated

def merge_association(hash, key, serializables, unique_values)
  already_serialized = (unique_values[key] ||= {})
  serializable_hashes = (hash[key] ||= [])
  serializables.each do |serializable|
    unless already_serialized.include? serializable.object
      already_serialized[serializable.object] = true
      serializable_hashes << serializable.serializable_hash
    end
  end
end

def meta_key

def meta_key
  @options[:meta_key].try(:to_sym) || :meta
end

def model_class

The model class associated with this serializer.

def model_class
  name.sub(/Serializer$/, '').constantize
end

def perform_caching?

def perform_caching?
  perform_caching && cache && respond_to?(:cache_key)
end

def root(name)

Defines the root used on serialization. If false, disables the root.

def root(name)
  self._root = name
end

def root_name

def root_name
  return false if self._root == false
  class_name = self.class.name.demodulize.underscore.sub(/_serializer$/, '').to_sym unless self.class.name.blank?
  if self._root == true
    class_name
  else
    self._root || class_name
  end
end

def schema

figure out a way to decouple those two.
TODO: This is currently coupled to Active Record. We need to

to work.
methods on your custom models if you want the serializer's schema method
methods, provided by default by ActiveRecord. You can implement these
The schema method uses the +columns_hash+ and +reflect_on_association+

which is provided by +SerializerClass.model_class+.
This information is extracted from the serializer's model class,

{ :my_posts => { :has_many => :posts }

the hash looks like this:

end
has_many :posts, :key => :my_posts
class PostsSerializer < ActiveModel::Serializer

If :key is used:

{ :posts => { :has_many => :posts } }
The +associations+ hash looks like this:

{ :name => :string, :age => :integer }

The +attributes+ hash looks like this:

The schema hash has two keys: +attributes+ and +associations+.

can be used to generate clients for the serialized output.
Return a schema hash for the current serializer. This information

def schema
  klass = model_class
  columns = klass.columns_hash
  attrs = {}
  _attributes.each do |name, key|
    if column = columns[name.to_s]
      attrs[key] = column.type
    else
      # Computed attribute (method on serializer or model). We cannot
      # infer the type, so we put nil, unless specified in the attribute declaration
      if name != key
        attrs[name] = key
      else
        attrs[key] = nil
      end
    end
  end
  associations = {}
  _associations.each do |attr, association_class|
    association = association_class.new(attr, self)
    if model_association = klass.reflect_on_association(association.name)
      # Real association.
      associations[association.key] = { model_association.macro => model_association.name }
    else
      # Computed association. We could infer has_many vs. has_one from
      # the association class, but that would make it different from
      # real associations, which read has_one vs. belongs_to from the
      # model.
      associations[association.key] = nil
    end
  end
  { :attributes => attrs, :associations => associations }
end

def scope

Returns options[:scope]

def scope
  @options[:scope]
end

def serializable_hash

object without the root.
Returns a hash representation of the serializable

def serializable_hash
  if perform_caching?
    cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'serializable-hash']) do
      _serializable_hash
    end
  else
    _serializable_hash
  end
end

def to_json(*args)

def to_json(*args)
  if perform_caching?
    cache.fetch expand_cache_key([self.class.to_s.underscore, cache_key, 'to-json']) do
      super
    end
  else
    super
  end
end

def url_options

def url_options
  @options[:url_options] || {}
end

Modules

Classes