How to set ActiveModel::Base.include_root_in_json to false?

Question

I'm using Rails 3 w/ Mongoid, (so no ActiveRecord). Mongoid uses ActiveModel's "to_json" method, and by default that method includes the root object in the JSON (which I don't want).

I've tried putting this in an initializer:

ActiveModel::Base.include_root_in_json = false

But get the error

uninitialized constant ActiveModel::Base

Any ideas how I can change this? I changed the default directly in the source-code and it worked fine, but obviously I'd like to do it properly.

The variable is defined at the top of this file: Github - activemodel/lib/active_model/serializers/json.rb

From the docs: "The option ActiveModel::Base.include_root_in_json controls the top-level behavior of to_json. It is true by default."

Answer 1

ActiveModel::Base.include_root_in_json = false

in an initializer??

Answer 2

I know this is old, but another way you can do this is by placing this within your application class in application.rb:

# When JSON-encoding a record, don't wrap the attributes in a hash where the
# key is named after the model
config.active_record.include_root_in_json = false

Answer 3

You should simply set it on the class that includes the ActiveModel modules:

class Person
  include ActiveModel::Validations
  include ActiveModel::Serializers::JSON
  self.include_root_in_json = false

  ...
end

Answer 4

If you prefer initializers, it's ActiveRecord::Base, not ActiveModel::Base in Rails versions 2.* and 3.1, possibly 3.0. Looked through the source, and in 3.0 beta it was switched to ActiveModel, but back again to ActiveRecord at some point.

ActiveRecord::Base.include_root_in_json = false

Also, in case you're actually trying to use this functionality, in Rails 3.1 the params wrapper is relevant:

ActionController::ParamsWrapper

Wraps the parameters hash into a nested hash. This will allow clients to submit POST requests without having to specify any root elements.

http://edgeapi.rubyonrails.org/classes/ActionController/ParamsWrapper.html