fresh?

# File actionpack/lib/action_controller/request.rb, line 136
    def fresh?(response)
      case
      when if_modified_since && if_none_match
        not_modified?(response.last_modified) && etag_matches?(response.etag)
      when if_modified_since
        not_modified?(response.last_modified)
      when if_none_match
        etag_matches?(response.etag)
      else
        false
      end
    end