wordpress redirect tiny post url to long post slug

wordpress redirect tiny post url to long post slug.php

<?php
/*
  **** into functions.php ****
  Example:
  redirect tiny url: http://site.com/?p=1
  to long post slug: http://site.com/my-post/
*/
add_action('template_redirect', 'redirect_tiny_url_to_long');
function redirect_tiny_url_to_long(){
    if(is_single()){
				if(isset($_GET['p']) && is_numeric($_GET['p']) && intval($_GET['p'])){
					$p_id = (int)intval($_GET['p']);
					if($p_id != 0){
						$post_link = get_permalink($p_id);
						if($post_link && !empty($post_link) && stripos($post_link, '?p='.$p_id) === false){
							wp_redirect( $post_link, 301 );
							exit();
						}
					}
				}
    }
		return;
}