Create subdomains on the fly with .htaccess (PHP)

Question

I am looking to create a system which on signup will create a subdomain on my website for the users account area.

e.g. johndoe.website.com

I think it would

Answer 1

You could allow every subdomain in the first place and then check if the subdomain is valid. For example:

RewriteEngine on
RewriteCond %{HTTP_HOST} ^[^.]+\.example\.com$
RewriteRule !^index\.php$ index.php [L]

Inside the index.php you can than extract the subdomain using:

if (preg_match('/^([^.]+)\.example\.com$/', $_SERVER['HTTP_HOST'], $match)) {
    var_dump($match[1]);
}

But all this requires that your webserver accepts every subdomain name.