Help with nginx regex

Question

Nginx

There is a config, something like this

server {
    listen 80;
    server_name ~^(?:www\.)?(?P<host_wo_www>.+)$;
    server_name_in_redirect     off;
    resolver    127.0.0.1;

Accordingly, the full domain name without www gets into the $host_wo_www variable, but I need to get one more variable so that only the third-level subdomain gets there, that is, we have www.subdomain.domain.com, I need to have a variable where only the subdomain gets, maybe someone help with the routine?

Answer 1

I got this:
server_name ~^(?:www\.)?(?P.+)?\.(?P[^\.]+\.[^\.]+)$;
If there are more than 3 parts in the domain, then the "extra" ones go to the subdomain:
abc.def.ghi.ru ->abc.def + ghi.ru