code: func RequireCron(c *router.Context, next router.Handler) {
  	if !devAppserverBypassFn(c.Context) {
  		if c.Request.Header.Get("X-Appengine-Cron") != "true" {
  			logging.Errorf(c.Context, "request not made from cron")
  			http.Error(c.Writer, "error: must be run from cron", http.StatusForbidden)
  			return
  		}
  	}
  	next(c)
  }
docs: // RequireCron ensures that the request is from the appengine 'cron' service.
  //
  // It checks the presence of a magical header that can be set only by GAE.
  // If the header is not there, it aborts the request with StatusForbidden.
  //
  // This middleware has no effect when using 'BaseTest' or when running under
  // dev_appserver.py