basic http authentication

Hi,
I used code from
http://railscasts.com/episodes/82-http-basic-authentication
but added it to Application controller to apply to the whole
application
class ApplicationController < ActionController::Base
  protect_from_forgery

  before_filter :authenticate

  protected
  def authenticate
    puts 'authenticating.. '
    authenticate_or_request_with_http_basic do |username, password|
      username == "foo" && password == "bar"
    end
  end
end

that does not seem to work... any ideas why?