Module ActiveModel::Serializers::JSON

Returns a hash representing the model. Some configuration can be passed through options.

The option include_root_in_json controls the top-level behavior of as_json. If true (the default) as_json will emit a single root node named after the object’s type. For example:

  user = User.find(1)
  user.as_json
  # => { "user": {"id": 1, "name": "Konata Izumi", "age": 16,
                  "created_at": "2006/08/01", "awesome": true} }

  ActiveRecord::Base.include_root_in_json = false
  user.as_json
  # => {"id": 1, "name": "Konata Izumi", "age": 16,
        "created_at": "2006/08/01", "awesome": true}

This behavior can also be achieved by setting the :root option to false as in:

  user = User.find(1)
  user.as_json(root: false)
  # =>  {"id": 1, "name": "Konata Izumi", "age": 16,
         "created_at": "2006/08/01", "awesome": true}

The remainder of the examples in this section assume include_root_in_json is set to false.

Without any options, the returned Hash will include all the model’s attributes. For example:

  user = User.find(1)
  user.as_json
  # => {"id": 1, "name": "Konata Izumi", "age": 16,
        "created_at": "2006/08/01", "awesome": true}

The :only and :except options can be used to limit the attributes included, and work similar to the attributes method. For example:

  user.as_json(:only => [ :id, :name ])
  # => {"id": 1, "name": "Konata Izumi"}

  user.as_json(:except => [ :id, :created_at, :age ])
  # => {"name": "Konata Izumi", "awesome": true}

To include the result of some method calls on the model use :methods:

  user.as_json(:methods => :permalink)
  # => {"id": 1, "name": "Konata Izumi", "age": 16,
        "created_at": "2006/08/01", "awesome": true,
        "permalink": "1-konata-izumi"}

To include associations use :include:

  user.as_json(:include => :posts)
  # => {"id": 1, "name": "Konata Izumi", "age": 16,
        "created_at": "2006/08/01", "awesome": true,
        "posts": [{"id": 1, "author_id": 1, "title": "Welcome to the weblog"},
                  {"id": 2, author_id: 1, "title": "So I was thinking"}]}

Second level and higher order associations work as well:

  user.as_json(:include => { :posts => {
                                 :include => { :comments => {
                                               :only => :body } },
                                 :only => :title } })
  # => {"id": 1, "name": "Konata Izumi", "age": 16,
        "created_at": "2006/08/01", "awesome": true,
        "posts": [{"comments": [{"body": "1st post!"}, {"body": "Second!"}],
                   "title": "Welcome to the weblog"},
                  {"comments": [{"body": "Don't think too hard"}],
                   "title": "So I was thinking"}]}