How to create virtual subdomains on the fly?

How can I rewrite rules to create virtual subdomains on the fly that are
only used to pass variables to a PHP file?

For instance people access:

steel.suppliers.com

And the servers executes:

http://suppliers.com/cat.php?id=steel

I don't pretend creating actual subdomains. It would only be a shortcut
for visitors. There is going to be hundreds or thousands of names, and
it's impossible to create subdomains by hand...

Is there a way to do it?
Thanks,

--
Justin.
http://www.opera.com/m2/

"Justin Sane" <me@privacy.net> schreef in bericht
news:op.ssssjtnagl9owm@sony...
> How can I rewrite rules to create virtual subdomains on the fly that are
> only used to pass variables to a PHP file?
> For instance people access:
> steel.suppliers.com
> And the servers executes:
> http://suppliers.com/cat.php?id=steel
>
Try using a permanent redirect
RewriteCond %{HTTP_HOST} !^www.suppliers.com$ [NC]
RewriteCond %{HTTP_HOST} (.*).suppliers.com$ [NC]
RewriteRule ^/?$ http://www.suppliers.com/cat.php?id=%1 [L, R=302]
to redirect only the initial request.

or try redirecting any request transparently
RewriteCond %{HTTP_HOST} .*(.*).suppliers.com$ [NC]
RewriteRule ^(.*) /cat.php/$1?id=%1 [L,NE]
having cat.php accept the original request as PATH_INFO

or be blund and have cat.php read HTTP_HOST and do its thing!

Just some untested thoughts ...

HansH

HansH