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.

Answer 2

Gotta love regex with NGINX!

As I often work with multiple domain-names and I like to keep my configs as clean and rock solid as possible I almost always use regex with nginx.

In this case I've solved it with the following regex:

server {
    listen 80;
    server_name ~^((?<subdomain>.*)\.)(?<domain>[^.]+)\.(?<tld>[^.]+)$;
    return 301 $scheme://${domain}.${tld};
}

What this does is the following: every subdomain.domain-name.tld that points to this server (ip address) is automatically redirected to domain-name.tld.

So for instance www.myexampledomain.com is redirected to myexampledomain.com.

To answer the question, what you could also do is the following:

server {
    listen 80;
    server_name ~^((?<subdomain>.*)\.)(?<domain>[^.]+)\.(?<tld>[^.]+)$;
    return 301 $scheme://${domain}.${tld}/${subdomain};
}

Now mysubdomain.myexampledomain.com is converted into myexampledomain.com/mysubdomain.

Above regex is great as you can throw anything at it that you like and it will convert it for you.