application_controller.rb

  # To specify custom behavior that will be taken if the validation fails, pass a block to this method.
  # It'll be called with |reason, default_action_as_proc|
  def validate_rights(action, object = nil, message = nil)
    @validate_rights_has_been_called = true
    return true if action == :unprotected
    take_action = false
    respond_to do |format|
      if !logged_in?
        reason = :not_logged_in
        format.html do
          take_action = lambda do
            session[:redirect_url] = request.url
            flash[:notice] = "You must be logged in to do that"
            redirect_to login_path and return false
          end
        end
        format.js do
          take_action = lambda { head :unauthorized and return false }
        end
      else
        reason = :acl_failed
        format.html do
          unless current_user.is_allowed_to?(action, object)
            take_action = lambda do
              flash[:notice] = message if message.present?
              redirect_to(login_path) and return false
            end
          end
        end
        format.js do
          unless current_user.is_allowed_to?(action, object)
            take_action = lambda { render_bad_request and return false }
          end
        end
        format.csv do
          unless current_user.is_allowed_to?(action, object)
            take_action = lambda { render_bad_request and return false }
          end
        end
      end
    end
    if take_action
      block_given? ? yield(reason, take_action) : take_action.call
    end
    true
  end