virtual document root for Nginx

nginx_virtual_document_root.conf

# [0-9].example.com -> /srv/tickets.example.com/[0-9]/app/build
# http://nginx.org/en/docs/http/server_names.html

server {

    listen 80;
    server_name "~^(?<subdomain>^\d).example.com$";
    root /srv/tickets.example.com/$subdomain/app/build;

}

nginx_virtual_document_root_v2.conf

# [projectname].[user].example.com -> /home/$user/dev/$projectname/web;

server {

    listen 81;
    server_name "~^(?<project>.+)\.(?<user>.+)\.example\.com$";
    root /home/$user/dev/$project/web;

}