PHP implementation file forced download code

/**
* php force download file
* edit: bbs.it-home.org
*/
$file_dir = "./";
$name = "test.txt";
$file = fopen($file_dir.$name," r");
Header("Content-type: application/octet-stream");
Header("Accept-Ranges: bytes");
Header("Accept-Length: ".filesize($file_dir . $name) );
Header("Content-Disposition: attachment; filename=".$name);
echo fread($file, filesize($file_dir.$name));
fclose($file);
?>

The code is very simple. It mainly focuses on learning the principles and implementation methods of forced downloading of files in PHP. You can improve on this basis.