def in_time_window?
        @@time_window = 4 if @@time_window < 4
        minutes = (@@time_window / 2).floor
        ts = Chronic.parse @http_headers[@@header_timestamp]
        before = Time.now.utc - 60*minutes
        after = Time.now.utc + 60*minutes
        if ts.nil?
          @errors << "timestamp was in an invalid format; should be YYYY-MM-DD HH:MM:SS UTC"
          return false
        end
        ts > before && ts < after
      end
def in_time_window?
        @@time_window = 4 if @@time_window < 4
        minutes = (@@time_window / 2).floor
        ts = Chronic.parse @http_headers[@@header_timestamp]
        before = Time.now.utc - 60*minutes
        after = Time.now.utc + 60*minutes
        if ts.nil?
          @errors << "timestamp was in an invalid format; should be YYYY-MM-DD HH:MM:SS UTC"
          return false
        end
        ts > before && ts < after
      end
determines if given timestamp is within a specific window of minutes