Post ID instead of the slug in the Friendly URL for the post type – “post_type_/ID”

Suppose, when registering the post type orders using register_post_type() parameter rewrite = false - the rewrite rules are not created and must be generated manually.

The URL should look like example.com/orders/123, where 123 is the post ID.

add_action( 'init', function(){

	// Create friendly URL rules
	add_rewrite_tag( '%order_id%', '([0-9]+)', "post_type=orders&p=" );

	// or you can do it this way
	// create CNC rules - here 'order/([0-9]+)/?$' is exactly
	// the same as what add_permastruct() would create and so it replaces...
	//add_filter( 'orders'.'_rewrite_rules', function( $rules ){
	//  return array( 'order/([0-9]+)/?$' => 'index.php?post_type=orders&p=$matches[2]' );
	//} );

	// register the structure for the post type
	add_permastruct( 'orders', 'order/%order_id%', array(
		'with_front'  => false,
		'paged'       => false,
		'feed'        => false,
		'forcomments' => false,
		'walk_dirs'   => false,
		'endpoints'   => false,
	) );

	// Replace the slug in the URL with an ID
	add_filter( 'post_type_link', 'orders_permalink', 1, 2 );

	function orders_permalink( $permalink, $post ){

		if( false === strpos( $permalink, '%order_id%' ) ){
			return $permalink;
		}

		return str_replace( '%order_id%', $post->ID, $permalink );
	}

} );