+ new_preferences[preference.k] = preference
+ end
+
+ old_preferences.each_value(&:delete)
+
+ new_preferences.each_value(&:save!)
+
+ render :text => "", :content_type => "text/plain"
+ end
+
+ ##
+ # update the value of a single preference
+ def update_one
+ begin
+ pref = UserPreference.find([@user.id, params[:preference_key]])
+ rescue ActiveRecord::RecordNotFound
+ pref = UserPreference.new
+ pref.user = @user
+ pref.k = params[:preference_key]