如何实现webhook通知

Question

在开发中，有些外部系统需要依赖我们系统的数据，如系统数据发生变更需要告知外部系统(外部系统可能有很多个)，我们初步想用webhook的方式来实现，想知道webhook是怎么用的。怎么搭建需要什么技术

Answer 1

webhook 的概念很简单，webhook 就是一个简单的 HTTP 回调。当发生某些事情时，HTTP POST 调用的注册 URL 作为简单通知。

换句话说，我们所说的 Webhook 是在 Web 应用程序中，当某些事情发生时，通过 HTTP POST 调用自动注册的 URL 以通知 Web 应用程序上的用户您请求的数据状态已更改，请查看它。

1.> 首先，我们将创建一个 API，从用户那里获取 KYC 信息，然后通过 RestTemplate 将此信息发送给第三方应用程序以验证用户信息，第三方将 Json Response 作为 KYC 详细信息提交返回给用户.

UserKYCController class

package com.example.com.controller;

@Api
@RestController
@RequestMapping(value = UrlConstant.BASE_URI_V1)
public class UserKYCController {

    private Logger logger = LoggerFactory.getLogger(UserKYCController.class);

    @Autowired
    private UserKYCService userKYCService;

    /**
     * @param userKYCInput
     * @param result
     * @return
     */
    @RequestMapping(value = UrlConstant.UPLOAD_CONSUMER_KYC_DOCUMENT, method = RequestMethod.POST)
    public ResponseEntity<Object> uploadKYCDetails(@Valid @RequestBody UserKYCInput userKYCInput,
            BindingResult result) {

    if (result.hasErrors()) {
    return ResponseHandler.response(HttpStatus.BAD_REQUEST, true, ErrorCollectionUtil.getError(result),
    ErrorCode.ERROR, Message("bad.request"),
    ResponseCode.ACKNOWLEDGE_OPTIONAL_RESPONSE_OBJECT, ErrorCollectionUtil.getErrorMap(result));
    }

    ResponseEntity<String> response = userKYCService.sendUserKyc(userKYCInput);
    if (response != null) {
    return ResponseHandler.response(HttpStatus.OK, false, Message("user.KYC.save.success"),
    ErrorCode.OK, ResponseCode.ACKNOWLEDGE, response);
    } else {
    genericUtil.saveData(userKYCInput);
    return ResponseHandler.response(HttpStatus.INTERNAL_SERVER_ERROR, true,
    Message("user.KYC.save.failure"), ErrorCode.ERROR,
    ResponseCode.ACKNOWLEDGE_OPTIONAL_RESPONSE_OBJECT);
    }
    }

}
 
 

UserKYCServiceImpl class

package com.example.com.service.Userkyc;


@Service
public class UserKYCServiceImpl implements UserKYCService {

    public static final Logger logger = LoggerFactory.getLogger(UserKYCServiceImpl.class);

    @Autowired
    private UserKYCRepository userKYCRepository;

    @Value("${user.kyc.restTemplate.url}")
    private String kycClientURL;

    @Value("${user.kyc.restTemplate.authKey}")
    private String kycAuthKey;

    @Autowired
    private UserService userService;
    
    @Override
    public ResponseEntity<String> sendUserKyc(UserKYCInput userKYCDetail) {
        RestTemplate restTemplate = new RestTemplate();
        String url = kycClientURL;
        String base64Creds = kycAuthKey;

        HttpHeaders headers = new HttpHeaders();
        headers.add("Authorization", "Basic " + base64Creds);
        HttpEntity<UserKYCInput> request = new HttpEntity<>(userKYCDetail, headers);
        ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.POST, request, String.class);
        uploadUserKyc(userKYCDetail, response);
        return response;
    }

    
}

2.> 其次，我们将创建另一个 API，并且此 API URL 已在发送用户 KYC 信息的第三方应用程序中注册，当验证成功时，第三方将使用更新的 Json 响应自动调用我们注册的 URL，或者我们可以说用户会通过调用这个注册 URL 被第三方自动通知，所以这个 URL 被称为（Webhook URL）。

UserKYCWebhookController class

package com.example.com.controller;

@Api
@RestController
@RequestMapping(value = UrlConstant.BASE_KYC_WEBHOOK_URI_V1)
public class UserKYCWebhookController {

    private static final Logger logger = getLogger(UserKYCWebhookController.class);

    @Autowired
    private UserKYCService userKYCService;

    @Autowired
    private WebHookDetailsService webHookDetailsService;

    @Autowired
    private PasswordEncoderUtil passwordEncoderUtil;
    
    /**
     * @param notificationDto
     * @param httpRequest
     * @throws Exception
     */
    @RequestMapping(value = UrlConstant.CONSUMER_KYC_WEBHOOK_NOTIFICATION_REQUEST, method = RequestMethod.POST)
    public void getKYCWebhookData(@RequestBody Map<String, Object> notificationDto,HttpServletRequest httpRequest) {

    final String authorization = httpRequest.getHeader("Authorization");
    logger.debug("authorization {}", authorization);
    if (authorization != null && authorization.startsWith("Basic")) {
    String base64Credentials = authorization.substring("Basic".length()).trim();
    String credentials = new String(Base64.getDecoder().decode(base64Credentials), Charset.forName("UTF-8"));
    final String[] values = credentials.split(":", 2);
    String userName = values[0].trim();
    String password = values[1].trim();

    WebHookDetails details = webHookDetailsService.getwebHookDetailsByUserName(userName);

    if (Objects.nonNull(details)) {

    String tid = notificationDto.get("tid").toString();
    String state = notificationDto.get("state").toString();
                
    Map<String, Object> response = new HashMap<>();
    response.put("tid", tid);
    response.put("state", state);

    if (passwordEncoderUtil.matches(password, details.getPassword())) {
    userKYCService.saveWebhookUpdatedResponse(response);
    } else {
    logger.debug("response == {}", false);
    }

    }
    }
    }

}

这就是使用 spring web 应用程序实现 webhook 的全部内容。