Custom post type with Post ID as slug for single post - WordPress

In one of my recent project, our client need unique URL for single posts in a custom post type.

normally I prefer Post Title as slug and it always improve our SEO. We can achieve this SEO friendly URL from the permalink settings. But same time, I need Post ID as slug for single post in one custom post type only.

Each post in WordPress have a post ID and it is always unique one. So we can use this ID as an unique slug.

To do so, we have to use filter function for post_type_link filter hook and our custom rewrite rule. Please check the below code snippet. You have to edit the code snippet according to your post type.

1) Register post type

function create_post_type_mycustomname() {
	$args = array(
		'capability_type' => 'post',
		'has_archive' => 'mycustomname',
		'rewrite' => array(
			'slug' => '/mycustomname',
			'feeds' => false
		)
	);

	register_post_type('ctp_mycustomname', $args);
}
add_action('init', 'create_post_type_mycustomname');

function mycustomname_links($post_link, $post = 0) {
	if($post->post_type === 'ctp_mycustomname') {
		return home_url('mycustomname/' . $post->ID . '/');
	}
	else{
		return $post_link;
	}
}
add_filter('post_type_link', 'mycustomname_links', 1, 3);

3) Add rewrites rules

function mycustomname_rewrites_init(){
	add_rewrite_rule('mycustomname/([0-9]+)?$', 'index.php?post_type=ctp_mycustomname&p=$matches[1]', 'top');
}
add_action('init', 'mycustomname_rewrites_init');