Example:
Router::attach('app', array(
'absolute' => true,
'host' => '{:subdomain:[a-z]+}.{:hostname}.{:tld}',
'scheme' => '{:scheme:https://}',
'prefix' => ''
));
$result = Router::attached('app', array(
'subdomain' => 'app',
'hostname' => 'blog',
'tld' => 'co.uk'
));
Will give the following array in $result:
array(
'absolute' => true,
'host' => 'blog.mysite.co.uk',
'scheme' => 'http://',
'prefix' => ''
));