docs: function onDecision(err, target) {
      //
      // If there was no target then this is a 404 by definition
      // even if it exists in the public registry because of a
      // potential whitelist.
      //
      if (err || !target) {
        return self.notFound(req, res, err || { message: 'Unknown pkg: ' + pkg });
      }
  
      // if X-Forwarded-Host is set, npm returns 404 {"error":"not_found","reason":"no_db_file"}
      if (req.headers["x-forwarded-host"]) delete req.headers["x-forwarded-host"];
  
      //
      // If we get a valid target then we can proxy to it
      //
      self.log.info('[decide] %s - %s %s %s %j', address, req.method, req.url, target.vhost || target.host || target.hostname, req.headers);
  
      self.emit('headers', req, req.headers, target);
  
      req.headers.host = target.vhost || target.host || target.hostname;
      proxy.web(req, res, {
        target: target.href
      });
    }