JSONObject invoke()

in gateway-discovery-ambari/src/main/java/org/apache/knox/gateway/topology/discovery/ambari/RESTInvoker.java [101:177]
61 lines of code
15 McCabe index (conditional complexity)

    JSONObject invoke(String url, String username, String passwordAlias) {
        JSONObject result = null;

        try {
            HttpGet request = new HttpGet(url);

            // If no configured username, then use default username alias
            String password = null;
            if (username == null) {
                if (aliasService != null) {
                    try {
                        char[] defaultUser = aliasService.getPasswordFromAliasForGateway(DEFAULT_USER_ALIAS);
                        if (defaultUser != null) {
                            username = new String(defaultUser);
                        }
                    } catch (AliasServiceException e) {
                        log.aliasServiceUserError(DEFAULT_USER_ALIAS, e.getLocalizedMessage());
                    }
                }

                // If username is still null
                if (username == null) {
                    log.aliasServiceUserNotFound();
                    throw new ConfigurationException("No username is configured for Ambari service discovery.");
                }
            }

            if (aliasService != null) {
                // If no password alias is configured, then try the default alias
                if (passwordAlias == null) {
                    passwordAlias = DEFAULT_PWD_ALIAS;
                }

                try {
                    char[] pwd = aliasService.getPasswordFromAliasForGateway(passwordAlias);
                    if (pwd != null) {
                        password = new String(pwd);
                    }

                } catch (AliasServiceException e) {
                    log.aliasServicePasswordError(passwordAlias, e.getLocalizedMessage());
                }
            }

            // If the password could not be determined
            if (password == null) {
                log.aliasServicePasswordNotFound();
                throw new ConfigurationException("No password is configured for Ambari service discovery.");
            }

            // Add an auth header if credentials are available
            String encodedCreds = Base64.getEncoder().encodeToString((username + ":" + password).getBytes(StandardCharsets.UTF_8));
            request.addHeader(new BasicHeader("Authorization", "Basic " + encodedCreds));

            // Ambari CSRF protection
            request.addHeader("X-Requested-By", "Knox");

            try(CloseableHttpResponse response = httpClient.execute(request)){
              if (HttpStatus.SC_OK == response.getStatusLine().getStatusCode()) {
                HttpEntity entity = response.getEntity();
                if (entity != null) {
                  result = (JSONObject) JSONValue.parse((EntityUtils.toString(entity)));
                  log.debugJSON(result.toJSONString());
                } else {
                  log.noJSON(url);
                }
              } else {
                log.unexpectedRestResponseStatusCode(url, response.getStatusLine().getStatusCode());
              }
            }
        } catch (ConnectTimeoutException e) {
            log.restInvocationTimedOut(url, e);
        } catch (IOException e) {
            log.restInvocationError(url, e);
        }
        return result;
    }