``` public function urlShort($shop_id=null){ $url=config('config.admin_url').$shop_id; $url= crc32($url); $result= sprintf("%u", $url); $sUrl= ''; while($result>0){ $s= $result%62; if($s>35){ $s= chr($s+61); } elseif($s>9 && $s<=35){ $s= chr($s+ 55); } $sUrl.= $s; $result= floor($result/62); } return $sUrl.$shop_id; } ```