GZIPService

public static class GZIPService extends Service {
public String path() { return "/some.file"; }
public void filter(Event event) throws Event, Exception {
event.reply().header("Content-Encoding", "gzip");

        File to = compress();
        FileInputStream in = new FileInputStream(to);
        Deploy.pipe(in, event.reply().output(to.length()));
        in.close();
    }

    public synchronized File compress() {
        File from = new File("app/content/some.file");
        File to = new File("app/content/some.file.gzip");

        boolean zip = false;

        if(to.exists()) {
            if(from.lastModified() > to.lastModified()) {
                zip = true;
            }
        }
        else {
            to.createNewFile();
            zip = true;
        }

        if(zip) {
            FileInputStream in = new FileInputStream(from);
            GZIPOutputStream out = new GZIPOutputStream(new FileOutputStream(to));

            Deploy.pipe(in, out);

            out.finish();
            out.close();
            in.close();
        }

        return to;
    }
}

You could also zip the files before deployment.