// 302 = "Moved temporarily"
static NanoHTTPD.Response serveRedirect(S url, S contentType default NanoHTTPD.MIME_PLAINTEXT) {
  NanoHTTPD.IStatus status = new NanoHTTPD.IStatus() {
    public String getDescription() { ret "302 Moved temporarily"; }
    public int getRequestStatus() { ret 302; }
  };
  
  NanoHTTPD.Response r = NanoHTTPD.newFixedLengthResponse(
    status,
    contentType, "");
  r.addHeader("Location", url);
  ret r;
}