How to hide sitemap from public access via NGINX or Cloudflare?

Question

Nginx

Hello,
the site has a sitemap domain.com/sitemap_index.xml
, it is necessary that only search robots (Yandex, Google, Bing, Yahoo, Duckduckgo, etc.) have access to this sitemap and that it is closed to ordinary users.
Please tell me how can this be done through NGINX or using Cloudflare's WAF?

Answer 1

The difference between a search robot and a regular browser is only in the user agent, which is easy to fake. Of course, you can also add a check that IP addresses belong to search companies ... but why, in general? What is indexed by Google can be easily found in it.