I managed to find a solution thanks to Milo‘s previous answers on other related questions. I found this particular post Remove base slug in CPT & CT, use CT in permalink to be extremely helpful.
My initial CPT with grandparent relationship rewrite remains the same:
function cpt_child(){
$args = array(
//code
'rewrite' => array( 'slug' => '%grandparent%/%parent%', 'with_front' => false),
);
register_post_type( 'child', $args );
}
add_action( 'init', 'cpt_child' );
Then I update the permalink:
add_filter( 'post_type_link', 'filter_the_post_type_link', 1, 2 );
function filter_the_post_type_link( $post_link, $post ) {
switch( $post->post_type ) {
case 'child':
$post_link = get_bloginfo( 'url' );
$relationship_child = p2p_type('children_to_parents')->get_adjacent_items($post->ID);
$parent = $relationship['parent']->post_name;
$relationship_parent = p2p_type('parents_to_grandparents')->get_adjacent_items($parent['parent']->ID);
$grandparent = $relationship_parent['parent']->post_name;
$post_link .= "/{$grandparent}/";
$post_link .= "{$parent}/";
$post_link .= "{$post->post_name}";
break;
}
return $post_link;
}
Hooked into request and changed query based on request vars that match my needs. Added is_admin()
check to prevent request filter from changing the CPT’s back end.
// URL rewrite pages 404 fix
if ( ! is_admin() ) {
function svbr_fix_requests( $request ){
// if it's not a section request and request is not empty treat request as page or post
if( ( ! array_key_exists( 'section' , $request ) ) && ( ! empty($request) ) ){
$request['post_type'] = array( 'post', 'page' );
}
// return request vars
return $request;
}
add_filter( 'request', 'svbr_fix_requests' );
}
Because we changed the query vars we have to add template functionality.
// Use single_template filter to properly redirect to page.php and custom page templates
function svbr_get_template_file($single_template) {
global $post;
$page_custom_template = get_post_meta( $post->ID, '_wp_page_template', true );
if ($post->post_type == 'page') {
if($page_custom_template != 'default') {
// We are using a child theme, so get_stylesheet_directory()
$single_template = get_stylesheet_directory() . "https://wordpress.stackexchange.com/" . $page_custom_template;
}
else {
$single_template = get_template_directory() . '/page.php';
}
}
return $single_template;
}
add_filter( 'single_template', 'svbr_get_template_file' );
Last but not least we have to add the template class to the body for styling purposes.
// Add template class to body
add_filter( 'body_class', 'template_class_name' );
function template_class_name( $classes ) {
global $post;
$page_custom_template = get_post_meta( $post->ID, '_wp_page_template', true );
$page_custom_template = str_replace('.php','',$page_custom_template);
$page_custom_template="page-template-" . $page_custom_template;
// add 'class-name' to the $classes array
$classes[] = $page_custom_template;
// return the $classes array
return $classes;
}