Get files from folders out of public access and pass them to the browser

fileProxy.php

/**
 * @param string $fileName
 * @param string $mime
 * @param bool $download
 * @param string $path
 * @return mixed
 */
function fileProxy($fileName, $mime = 'auto', $download = false, $path = '/some/folder/')
{
	if (basename($fileName) != $fileName) {
		return 'Filename not valid!';
	}
	$path = substr($path, -1) == '/' ? $path : $path . '/';

	$file = $path . $fileName;
	if (!(file_exists($file) && is_readable($file))) {
		return 'The file "' . $fileName . '" could not be found!';
	}

	if ($mime === 'auto') {
		$finfo = finfo_open(FILEINFO_MIME_TYPE);
		$mime = finfo_file($finfo, $file);
		finfo_close($finfo);
	}

	ob_clean();

	if ($download === false) {
		header('Content-type: ' . $mime);
		header('Content-length: ' . filesize($file));

		$open = @fopen($file, 'rb');
		if ($open) {
			fpassthru($open);
			exit;
		}
	} else {

		// download
		$pathParts = pathinfo($file);
		header('Content-Disposition: attachment; filename="' . $pathParts["basename"] . '"');
		header('Content-type: application/octet-stream');
		header('Content-length: ' . filesize($file));
		header('Content-Disposition: filename="' . $pathParts["basename"] . '"');
		header('Cache-control: private'); // open files directly
		readfile($file);
		die;
	}
}