how to dynamically root by both domain and subdomain in nginx config

Question

I want to host several domain names, each with subdomains dynamically on my nginx server (ubuntu 14.04):

home/serve/
     domain1.com
        www
        subdomain1
        subdomain2
     domain2.com
        www
        subdomain1
        subdomain2

I want both www.domain1.com and domain1.com to root to /home/serve/domain1/www and subdomain1.domain1.com to root to /home/serve/domain1/subdomain1.

I have this working for the domain both with and without www. (see below) but I can't work out how I can extend this to enable the subdomain rooting as well.

server {
    listen 80 default_server;
    listen [::]:80 default_server ipv6only=on;

    server_name   ~^(www\.)?(?<domain>.+)$;

    root       /home/serve/$domain/www/;

    location / {
        index index.html index.htm index.php;
    }

    location ~ [^/]\.php(/|$) {
      fastcgi_split_path_info ^(.+?\.php)(/.*)$;
      fastcgi_param SCRIPT_FILENAME $document_root$fastcgi_script_name;
      fastcgi_pass unix:/var/run/php5-fpm.sock;
      fastcgi_index index.php;
      include fastcgi_params;
    }
}

Answer 1

You can extend your regular expression to include any subdomain, not just www. Also, it would be a good idea to set up the default folder in case the folder for the requested subdomain does not exist.

Something like this should work fine:

server_name ~^(?<subdomain>\w*?)?\.?(?<domain>\w+\.\w+)$;

if ($subdomain = "") {
    set $subdomain "www";
}

if (!-d "/home/serve/$domain/$subdomain") {
    set $subdomain "www";
}

root "/home/serve/$domain/$subdomain";

Note that even though using the "if" directive is usually inadvisable, in this particular case it is completely safe and acceptable, since these directives are defined in the server context.