隐藏下载地址的php代码

//show.php
//http://show.php?FileName=bGpjXzA2MDQxMzE3MTcyMS5YTFM=&&FileDir=VXNlckZpbGU=&&FileId=OTg2

if(!$level || empty($_GET['FileName'])|| empty($_GET['FileDir'])|| empty($_GET['FileId'])){echo'<script> alert("非法连接 !"); location.replace ("index.php") </script>'; exit();}
        
$file_name=base64_decode($_GET['FileName']);
$file_dir=base64_decode($_GET['FileDir']);
$FileId=base64_decode($_GET['FileId']);

$db = new dbClass($db_username,$db_password,$db_database);
$db->connect();
$db->select();
$db->update('FileInfo','DownNumber=DownNumber+1,LastlyTime=now()','Id="'.$FileId.'"');
$db->close();

$file_dir = $file_dir."/";
$file = fopen($file_dir . $file_name,"r"); // 打开文件 
// 输入文件标签
Header("Content-type: application/octet-stream");
Header("Accept-Ranges: bytes");
Header("Accept-Length: ".filesize($file_dir . $file_name));
Header("Content-Disposition: attachment; filename=" . $file_name);
// 输出文件内容
echo fread($file,filesize($file_dir . $file_name));
fclose($file);
exit();