String content;
        try (final InputStream in = responseData.getResponseBody()) {
            final ExtractData extractData = getExtractData(extractor, in, createExtractParams(responseData, crawlingConfig));
            content = extractData.getContent();
            if (fessConfig.isCrawlerDocumentFileIgnoreEmptyContent() && StringUtil.isBlank(content)) {
                return null;
            }