/** returns application if the masterSecret is valid for the request PushApplicationEntity */
  private Variant loadVariantWhenAuthorized(HttpServletRequest request) {
    // extract the pushApplicationID and its secret from the HTTP Basic
    // header:
    String[] credentials = HttpBasicHelper.extractUsernameAndPasswordFromBasicHeader(request);
    String variantID = credentials[0];
    String secret = credentials[1];

    final Variant variant = genericVariantService.findByVariantID(variantID);
    if (variant != null && variant.getSecret().equals(secret)) {
      return variant;
    }

    // unauthorized...
    return null;
  }