Put post ID on the custom post type URL

Question

I want to get this link structure mysite.com/sa/post-slug/post_id/ on my custom post-type.

This is the post_type:

// ex_article Post type
add_action( 'init', 'ex_article_init' );

function ex_article_init() {
    $args = array(
        'labels' => array(
            'name' => _x( 'Article', 'Post type general name', 'textdomain' ),
            'menu_name' => _x( 'Ex Article', 'Admin Menu text', 'textdomain' )
        ),
        'public' => true,
        'show_ui' => true,
        'hierarchical' => false,
        'rewrite' => array('slug' => 'sa', 'with_front'=>false ),
        ---
        ---
        ---
        );
    
    register_post_type( 'ex_article', $args );
}

On permalink setting, I use Post Name : mysite.com/sample-post/. Using a custom structure is not an option for me, I need to avoid it, and also it does nothing to custom post type.

Answer 1

It's quite easy, actually:

1. Change the generated permalink structure so that it ends with the post ID and not the post slug (but it still contains the post slug):

   // After you registered the post type:
   register_post_type( 'ex_article', $args );
   
   // .. run this code:
   global $wp_rewrite;
   $wp_rewrite->extra_permastructs['ex_article']['struct'] = 'sa/%ex_article%/%post_id%';
   

2. Then replace the post ID placeholder (%post_id%) in the generated permalink URL with the correct post ID:

   add_filter( 'post_type_link', function ( $post_link, $post ) {
       if ( $post && 'ex_article' === $post->post_type ) {
           return str_replace( '%post_id%', $post->ID, $post_link );
       }
       return $post_link;
   }, 10, 2 );
   

And don't forget to flush/regenerate the rewrite rules! Just visit the permalink settings page without having to click on the "save" button.