PHP script to download a file from files/ directory. Warning: no authorization or security checks implemented.

download.php

<?php

// You need to create the files/ directory inside your document root to put your files.

if (substr($_SERVER['REQUEST_URI'], 0, 7) !== '/files/') {
	die('not allowed');
}

$absolutePath = $_SERVER['DOCUMENT_ROOT'] . $_SERVER['REQUEST_URI'];

$pathParts = pathinfo($absolutePath);
$fileName = $pathParts['basename'];

$fileInfo = finfo_open(FILEINFO_MIME_TYPE);
$fileType = finfo_file($fileInfo, $absolutePath);
finfo_close($fileInfo);

$fileSize = filesize($absolutePath);

header('Content-Length: ' . $fileSize);
header('Content-Type: ' . $fileType);
header('Content-Disposition: attachment; filename=' . $fileName);

ob_clean();
flush();
readfile($absolutePath);

exit;

?>

htaccess

RewriteEngine On
RewriteCond %{REQUEST_URI} ^/files/.*$
RewriteCond %{DOCUMENT_ROOT}%{REQUEST_URI} -f
RewriteRule ^(.*)$ index.php [L]