Get Top parent url

Question

I have the following structure:

• TOP PAGE

  • SUB PAGE 1

  • --- SUB SUB PAGE 1

  • --- SUB SUB SUB PAGE 1

  • ---- SUB SUB SUB SUB PAGE 1

  • --- SUB SUB SUB PAGE 1

  • --- SUB SUB SUB PAGE 1

  • ---- SUB SUB SUB SUB PAGE 1

How can I get the TOP PAGE url from any of the SUB PAGES?

For example: Get TOP PAGE url from ---- SUB SUB SUB SUB PAGE 1

With this I can only get the previous page url and not the Top parent ulr

        if ( $post->post_parent ) {
            $parent_page_link = get_permalink( $post->post_parent ); // getting parent URL
        } 

There are many topics with related question but I can not solve my problem.

Thanks,

Answer 1

You have to do it in a loop:

$p = $post;
while ( $p->post_parent ) {
    $p = get_post( $p->post_parent );
}
$parent_page_link = get_permalink( $p->ID );

Another way is to use get_ancestors function:

$ancestors = get_ancestors( $post->ID, 'page', 'post_type' );
$root = ( ! empty( $ancestors ) ) ? end($ancestors) : $post->ID;
$parent_page_link = get_permalink( $root );