Functions wordpress

add_action('init', 'post_type_producten');
add_action( 'init', 'create_producten_taxonomies', 0 );

add_filter('post_type', 'projecten_permalinks', 1, 3);
add_filter('post_type_link', 'projecten_permalinks', 1, 3);

// ## PROJECTEN CUSTOM POST TYPE
function post_type_producten() {
    $labels = array(
        'name'                              => _x('Producten', 'post type general name'),
        'singular_name'             => _x('Producten', 'post type singular name'),
        'add_new'                       => _x('Nieuw product', 'producten'),
        'add_new_item'              => __('Nieuw product toevoegen'),
        'edit_item'                     => __('Product bewerken'),
        'new_item'                      => __('Nieuw Product'),
        'view_item'                     => __('Bekijk Product'),
        'search_items'              => __('Zoek Producten'),
        'not_found'                     =>  __('Geen producten gevonden'),
        'not_found_in_trash'    => __('Geen producten in de prullenbak'),
        'parent_item_colon'     => '');

    $args = array(
        'label'                     => __('Projecten'),
        'labels'                    => $labels,
        'public'                    => true,
        'hierarchical'      => false,
        'show_ui'               => true,
        'supports'              => array('title','editor','thumbnail','revisions'),
        'has_archive'       => true,
        'menu_position'     => 5,
        'taxonomies'            => array('productCat'),
        'rewrite'               => array(
            'slug'              => 'producten/%productCat%',
            'with_front'    => true,
            'hierarchical' => true
        )
    );
    register_post_type('producten', $args);
    flush_rewrite_rules();
}


//taxonomies registreren
function create_producten_taxonomies()
{
  // productCat
  $labels = array(
    'name' => _x( 'Product categorieën', 'taxonomy general name' ),
    'singular_name' => _x( 'Product categorieën', 'taxonomy singular name' ),
    'search_items' =>  __( 'Zoek Product categorieën' ),
    'all_items' => __( 'Alle categorieën' ),
    'parent_item' => __( 'Bovenliggende categorie' ),
    'parent_item_colon' => __( 'Hoofd categorie:' ),
    'edit_item' => __( 'Wijzig categorie' ),
    'update_item' => __( 'Update categorie' ),
    'add_new_item' => __( 'Nieuwe categorie' ),
    'new_item_name' => __( 'Nieuwe categorie naam' ),
    'menu_name' => __( 'Categorieën' ),
  );

  register_taxonomy('productCat',array('producten'), array(
    'hierarchical'  => true,
    'labels'                => $labels,
    'show_ui'           => true,
    'query_var'         => true,
    'rewrite'           => array( 'slug'                    => 'producten/%productCat%',
                                                        'hierarchical'  => true,
                                                        'with_front'        => false  )
  ));
  flush_rewrite_rules();
}


// Permalinks projecten

function projecten_permalinks( $post_link, $id = 0, $leavename = FALSE ) {
    if ( strpos('%productCat%', $post_link) < 0 ) {
        return $post_link;
    }
    $post = get_post($id);
    if ( !is_object($post) || $post->post_type != 'producten' ) {
        return $post_link;
    }
    $terms = wp_get_object_terms($post->ID, 'productCat');
    //print_r($terms);
    if ( !$terms ) {
        return str_replace('%productCat%', '', $post_link);
    }
    $perm = $terms[0]->slug;
    if(!empty($terms[1]->slug)) {
        $perm = $terms[0]->slug.'/'.$terms[1]->slug;
    }


    return str_replace('%productCat%', $perm, $post_link);
}