code: public static function getInterface()
      {
          $return = 'http';
          $isCliOrCron = \count(\array_filter(array(
              \defined('STDIN'),
              isset($_SERVER['argv']),
              !\array_key_exists('REQUEST_METHOD', $_SERVER),
          ))) > 0;
          if ($isCliOrCron) {
              // TERM is a linux/unix thing
              $return = isset($_SERVER['TERM']) || \array_key_exists('PATH', $_SERVER)
                  ? 'cli'
                  : 'cron';
          } elseif (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] == 'XMLHttpRequest') {
              $return = 'ajax';
          }
          return $return;
      }
docs: Returns cli, cron, ajax, or http
  
  @return string cli | cron | ajax | http