Wordpress alternative URL to archive page

Question

I have a custom post type named myalbums, so the url to archive page is http://mysite/gallery (I added 'rewrite' => ['slug' => 'gallery'] on it's creation).

So, I want to have an alternative URL like http://mysite/gallery/special to see the same page but with a little filter. On one page you can see some albums and on the alternative you can see anothers.

How can I do this, and how can I know when user is on one of them?

PS. I use Timber Wordpress

Answer 1

I just used rewrite api like this:

add_filter('query_vars', 'add_query_vars');
function add_query_vars($aVars) {
    $aVars[] = "my-var";
    return $aVars;
}

add_filter('rewrite_rules_array', 'add_rewrite_rules');
function add_rewrite_rules($aRules) {
    $aNewRules = array('gallery/special/([^/]+)/?$' => 'index.php?post_type=myalbums&my-var=$matches[1]');
    $aRules    = $aNewRules + $aRules;
    return $aRules;
}

No accessing to http://mysite/gallery/special/anything this request goes to archive.php file and I can get the var just calling $wp_query->query_vars['my-var'].