*/
    protected String normalizeCanonicalUrl(final String baseUrl, final String canonicalUrl) {
        try {
            final URL u = new URL(baseUrl);
            return new URL(u, canonicalUrl.startsWith(":") ? u.getProtocol() + canonicalUrl : canonicalUrl).toString();
        } catch (final MalformedURLException e) {
            logger.warn("Invalid canonical url: {} : {}", baseUrl, canonicalUrl, e);
        }
        return null;
    }