Remove and add www

Question

Nginx

Is it possible in nginx to add www. in the beginning, and for the third-level domain to clean? For example:
domain.ru -> www.domain.ru
www.some.domain.ru -> some.domain.ru

I would like to draw your attention to the fact that the domain name is unknown in advance.
I would like to see an example config

Answer 1

server {
server_name ~^(?\w\.\w)$;
rewrite ^/(.*)$ www. $domain/$1permanent;
}
server {
server_name ~^www\.(?\w\.\w\.\w)$;
rewrite ^/(.*)$ http://$domain/$1 permanent;
}
Somehow, I didn't write regexps for rfc compliance :)

Answer 2

Explain why this is?

Answer 3

ModeRewrite should help :) Unfortunately, I don’t know how it’s not called Ngnix correctly…