I have a requirement to specify a REGISTER max_expires based on the User-Agent.

I checked the docs and it seems there is no pseudo-variable or something like that would permit this.

I would like to be able to do something like this:

if($ua ~= "Some-UA") {

    $max_expires=100;

} else {

    $max_expires=150;

}

save("location");

Is there some way to achieve this?