I was using this as a directory index of sorts. It does all the things a normal directory index does, except that it also allows you to download a directory as a tar.gz. I don't remember how I set it up exactly, I remember there were some nginx rewrites needed

dir.php

<?php

$dir = $_GET['request_filename'];

if (is_dir($dir)) {
        if (!preg_match('/\/$/',$dir)) {
                header("Location: ".$_SERVER['REQUEST_URI'].'/');
                exit;
        }
        print "$dir<br/><br/>";

        $filenames = ls($dir);
        foreach($filenames as $full_name) {
                $pi = pathinfo($full_name); $relative_name = $pi['basename'];
                if (is_dir($full_name)) $relative_name .= '/';
                print "<a href=\"$relative_name\">$relative_name</a>";

                if (is_dir($full_name) && $relative_name != './' && $relative_name != '../') {
                        $tmp = rtrim($relative_name,'/');
                        print " [ <a href=\"$tmp.tar.gz\">tar.gz</a> ]";
                }

                print "<br/>\n";
        }
}
else if (preg_match('/(.+)\.tar\.gz$/',$dir,$matches)) {
        $pi = pathinfo($matches[1]);
        header("Content-Type: application/octet-stream");
        passthru("cd '{$pi['dirname']}' && tar cvf - '{$pi['basename']}' | gzip -c");
        exit;
}
else {
        show_404();
}

function show_404() {
        header("HTTP/1.0 404 Not Found");
        require_once("index.html");
        exit;
}

function ls($dir) {
        $dh = opendir($dir);
        $files = array();
        while (($file = readdir($dh)) !== false) {
                $files[] = $dir.$file;
        }
        closedir($dh);
        asort($files);
        return $files;
}

?>