How to make temporary expiring link for a downloadable file

Option 1: You can achieve this using htaccess if you have single download file/path. But if you have more files available for download. Creating a temporary file for each download requests and using htaccess is not a good idea.

$path="uploads/";
                  $actualfilename=$path.$filename;
                  $fakefilename="downloadfile.pdf";
                   if($typeofview=="download") {
                          @readfile($actualfilename);
                        header('Content-type: application/pdf');
                        header('Content-Disposition: attachment; filename="' . $fakefilename . '"');
                        header('Content-Transfer-Encoding: binary');
                        header('Content-Length: ' . filesize($actualfilename));
                        header('Accept-Ranges: bytes');
                        exit;

add this to your .htaccess file

RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule fakefile.php(.*)$ orignalfile.php?$1 [L,QSA]

Option 2:
Creating a symlink() for each file instead is a much better idea. This will save loads of disk space and keep down the server load.

Naming the symlink after the user’s session is a decent idea. A better idea is to generate a random symlink name & associate with the session, so the script can handle multiple downloads per session. You can use session_set_save_handler() (link) and register a custom read function that checks for expired sessions and removes symlinks when the session has expired.