rack-ok.rb

# When doing Cross Origin request from Internet Explor 8 & 9
# the XDomainRequest object must be used. This object does not
# give access to the response status code and *discards* the
# responseText for responses with status code other than 2xx.
#
# This Rack Middleware wraps the original response body and
# status code in a JSON object and always returns a 200 OK.
class Rack::Ok
  def initialize(app)
    @app = app
  end

  def call(env)
    status, headers, response = @app.call(env)

    if x_domain_request?(env)
      wrapped_response = MultiJson.dump({
        :status => status,
        :response => response.body
      })
      headers['Content-Type'] = 'application/json'
      [200, headers, [wrapped_response]]
    else
      [status, headers, response]
    end
  end

  # TODO check params if response must be 200
  def x_domain_request?(env)
    true
  end
end