Rails 3.2.x HTTP Basic 401 as JSON

401_json.rb

# Overload rails 3.2.x default HTTP Baisc 401 response
# to JSON instead of plain text/html.
#
# Examples
#
#   require 'json_401'
#   class ApiController < ActionController::Metal
#     ...
#   end
#
module ActionController::HttpAuthentication::Basic

  def authentication_request(controller, realm)
    controller.headers["WWW-Authenticate"] = %(Basic realm="#{realm.gsub(/"/, "")}")
    controller.response.headers["Content-Type"] = "application/json"
    controller.response_body = {error: "Access denied."}.to_json
    controller.status = 401
  end

end