Hi Sami,
I have an issue with the url_to_postid function too.
In wordpress the function get_item( $request ) from /wp-includes/class-wp-oembed-controller.php use the url_to_postid function. After I enabled the Custom Permalinks plugin and set a custom permalink for a page the get_item function return 0 for that page because the url_to_postid does not work with the custom permalink.
