Get the first letter of subdomain as variable

Question

How do I get the first letter of a variable in nginx

example

        server_name ~^(?<subdomain>\w+)\.development\.test$;

        location / {
                root /var/www/test/$subdomain.0/$subdomain;
                try_files $uri $uri/ =404;
        }

So this would work http://apple.development.test/ going to this path /var/www/test/a/apple

I have seen methods with map but not sure how to correctly do this

Answer 1

Following approach might work too:

server_name ~^(?<subdomain>(?<firstletter>\w)\w+)\.development\.test$;

location / {
    root /var/www/test/$firstletter/$subdomain;
    try_files $uri $uri/ =404;
}

Answer 2

You can create a new variable with the first letter using the map module: http://nginx.org/en/docs/http/ngx_http_map_module.html#map

Example:

map $subdomain $firstletter {
    default                    "";
    "~^(?letter.{1}).*$"  $letter;
}