Mod_Proxy with regex redirection

Question

I have a domainA.com which I would like to redirect it to:

domainB.com/public.php?service=shorty_relay&id=$1

So the input on the browser should be domainA.com/f7g6f87g and it should make a background redirection to domainB.com/public.php?service=shorty_relay&id=f7g6f87g, but keep the domain on the browser as is.

My virtual host lines are:

<VirtualHost *:80>
    ServerAdmin email@address.com
    DocumentRoot /var/www/dir
    ServerName domainA.com
    ServerAlias www.domainA.com
    ProxyPass / https://domainB.com/public.php?service=shorty_relay&id=$1
    ProxyPassMatch ^/([A-Za-z0-9]{4,12})$ https://domainB.com/public.php?service=shorty_relay&id=$1
    ProxyPassReverse / https://domainB.com/public.php?service=shorty_relay&id=$1
    ErrorLog /var/www/dir/error.log
</VirtualHost>

With the current lines Im able to redirect the domainA.com to the root of domainB.com. But its not what I need. I need the domainA.com to accept only valid ids (?service=shorty_relay& id=$1 ) I know somehow I have to combine this regex so I can allow only valid id.

 ProxyPassMatch ^/([A-Za-z0-9]{4,12})$ https://domainB.com/public.php?service=shorty_relay&id=$1

Any clues how can I make this possible. Im trying to figure this out days now but no luck.

Answer 1

Get rid of the ProxyPass line. That line works similar to the Redirect directive of mod_alias. It means anything after the / automatically gets appended to the end of the target URL, excluding query strings. That means $1 has no bearing in this directive because you're not using a regular expression to capture a match.

The only thing you should need is your ProxyPassMatch line:

ProxyPassMatch ^/([A-Za-z0-9]{4,12})$ https://domainB.com/public.php?service=shorty_relay&id=$1

Additionally, you don't need to include the query string in the ProxyPassReverse . This directive is used to "reverse" map redirects sent from domainB.com to a matching URL in domainA.com. So this should be enough:

ProxyPassReverse / https://domainB.com/public.php