private String getHeader(final ClassicHttpResponse response,
                             final String headerName) {
        try {
            final Header header = response.getHeader(headerName);
            return NullSafe.get(header, Header::getValue);
        } catch (final ProtocolException e) {
            LOGGER.error("Error getting header '{}': {}", headerName, LogUtil.exceptionMessage(e), e);
        }
        return null;
    }
Handler class that forwards the request to a URL.
stroom-proxy/stroom-proxy-app/src/main/java/stroom/proxy/app/handler/HttpSender.java