try (CloseableHttpResponse response = httpClient.execute(httpPost)) {
            if (response.getStatusLine().getStatusCode() != Constants.OK_STATUS_CODE) {
                logger.warn("Failed to access API extractor endpoint: url={}, statusCode={}", url,
                        response.getStatusLine().getStatusCode());
                return null;
            }

        } catch (final WebApiException e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to process a popularWord request.", e);
            }
            writeJsonResponse(e.getStatusCode(), e);
        } catch (final Exception e) {
            if (logger.isDebugEnabled()) {
                logger.debug("Failed to process a popularWord request.", e);
            }

                message = "[" + errorCode + "] Failed to access to Web API.";
                logger.warn(message, e);
            }
            response.sendError(e.getStatusCode(), message);
        }
    }

    /**
     * Processes API requests to the search engine.
     * Handles both regular API calls and plugin requests.
     *

            // get a content
            final HttpResponse response = executeHttpClient(httpGet);
            httpEntity = response.getEntity();

            final int httpStatusCode = response.getStatusLine().getStatusCode();
            if (httpStatusCode == 200) {

                // check file size
                final Header contentLengthHeader = response.getFirstHeader("Content-Length");