regex - Redirecting a subdomain with a regular expression in nginx

Question

The nginx documentation says that the server_name directive supports regular expressions. I've been banging my head against the wall trying to get even a trivial regex working.

I want http://subdomain.mydomain.com to redirect to http://mydomain.com/subdomain

Here is my code.

server {
  server_name "~^subdomain.mydomain.com$";
  rewrite ^ http://mydomain.com/subdomain;
}

Also, potentially noteworthy. Further down in the nginx config file there is a rule:

server {
  server_name *.mydomain.com
  ...
}

What am I doing wrong?

UPDATE:

It has been suggested that I not use regex for this... to offer a little more clarity: the trivial regex was simply for purposes of troubleshooting. The real regex will look more like...

server {
  server_name "~^.*(cvg|cincinnati).fakeairport(app)?.(org|com)$";
  rewrite ^ http://fakeairport.com/cincinnati;
}

server {
  server_name "~^.*(lex|lexington).fakeairport(app)?.(org|com)$";
  rewrite ^ http://fakeairport.com/lexington;
}

So it would be preferable to use regex.

Answer 1

To answer an old question to help others

using nginx 1.1.19 you can do the following:

server {
    server_name     ~^(?<subdomain>w+).domainA.com$;

    location / {
            rewrite ^ https://$subdomain.domainB.com$request_uri permanent;
    }
}

The subdomain before domainA.com is matched and stored in variable $subdomain which then can be used in the rewrite. This rewrites url like xxx.domainA.com to xxx.domainB.com with only one server directive.