how to break a variable into seperate variables in nginx using regex - regex

Question

I have a development server setup that does some dynamic rooting to allow me to set up quick test projects by detecting domain and subdomain in server_name and using it to set the root.
server_name ~^(?<subdomain>\w*?)?\.?(?<domain>\w+\.\w+)$;
This works well, allowing me to set the root path based on variables $subdomain and $domain
For a specific type of project though, I also need to be able to further split the subdomain variable into two variables base on if the subdomain contains a dash.
e.g.
mysubdomain should not split but remain as variable $subdomain,
but mysubdomain-tn would be seperated into 2 variable $subdomain and $version

Answer 1

You need to complicate your regular expression a bit more:
server_name ~^(?<subdomain>\w*?)(-(?<version>\w*?)?)?\.?(?<domain>\w+\.\w+)$;
EDIT:
There are several ways to debug an Nginx configuration, including the debugging log, echo module and, in some extreme situations, even using a real debugger. However, in most cases adding custom headers to the response is enough to get the necessary information.
For example, I tested the regular expression above using this simple configuration:
server {
listen 80;
server_name ~^(?<subdomain>\w*?)(-(?<version>\w*?)?)?\.?(?<domain>\w+\.\w+)$;
# Without this line your browser will try to download
# the response as if it were a file
add_header Content-Type text/plain;
# You can name your headers however you like
add_header X-subdomain "$subdomain";
add_header X-domain "$domain";
add_header X-version "$version";
return 200;
}
Then I added domains mydomain.local, mysubdomain-tn.mydomain.local and mysubdomain-tn.mydomain.local to my hosts file, opened them in a browser with open debug panel (F12 in most browsers) and got the results.