Wordpress masking multiple urls to the single page - wordpress

Question

I have a WordPress (4.0) site and the situation where multiple URLs are dynamically created. Something like this:
/api-page/111/222/
/api-page/aaa/bbb/
I need to point them to:
/api-page/?param1=111&param2=222
/api-page/?param1=aaa&param2=bbb
because only the "api-page" exists. On the "api-page" I have the shortcode that will handle the params.
I know how to redirect URLs with an htaccess file, but I need urls to stay as they are.
I manage to mask the urls with this line in an htaccess file:
RewriteRule ^api-page/(.+)/(.+)/$ /api-page/?param1=$1&param2=$2 [L]
But WordPress throws 404 errors.
How to accomplish this?

Answer 1

I found the solution. The solution not using htaccess. I put this snippet in the function.php file of the theme:
function api_rw_rules() {
global $wp;
$wp->add_query_var('param1');
$wp->add_query_var('param2');
add_rewrite_rule('api-page/(.+)/(.*)','index.php?pagename=api-page&param1=$matches[1]&param2=$matches[2]','top');
global $wp_rewrite;
$wp_rewrite->flush_rules();
}
add_action('init', 'api_rw_rules');
Last two lines in the function can be removed after setting rewrite rules
/*
global $wp_rewrite;
$wp_rewrite->flush_rules();
*/
The only downside of this solution is that variables are not available in the $_GET. They are available with get_query_var():
$param1 = get_query_var('param1');
$param2 = get_query_var('param2');