将几个REST调用与Spring Webflux结合起来

Question

@RequestMapping(value = "/endpoint1", method = RequestMethod.POST)
public Mono<String> businessService(@RequestBody ApiManagementWrapper apiManagementWrapper, ServerWebExchange httpRequest) {
    log.info("Handling /enpoint1");

    Mono<String> t = fetch(apiManagementWrapper, httpRequest);

    return t;
}

private Mono<String> fetch(ApiManagementWrapper apiManagementWrapper, ServerWebExchange httpRequest) {
    return this.webClientProxy
            .post()
            .uri("http://localhost:8081/something")
            .headers(httpHeaders ->  httpRequest.getRequest().getHeaders())
            .cookies(httpCookies -> httpRequest.getRequest().getCookies())
            .body(BodyInserters.fromPublisher(Mono.just(apiManagementWrapper.getEnterpriseMessage()), Object.class))
            .exchange()
            .flatMap(response -> response.bodyToMono(String.class));
}

private void login(ApiManagementWrapper apiManagementWrapper) {
    LinkedMultiValueMap<String, String> formData = new LinkedMultiValueMap<>();
    formData.add("username", "user1");
    formData.add("password", "user1");

    Mono<ClientResponse> response =  this.webClientRouteConfirmation
            .post()
            .uri("http://localhost:8383/login")
            .body(BodyInserters.fromFormData(formData))
            .exchange();

    response.subscribe(clientResponse -> {
        handleLogin(clientResponse.cookies().getFirst("JSESSION_ID"), apiManagementWrapper);
    });
}

private void handleLogin(ResponseCookie loginCookie, ApiManagementWrapper apiManagementWrapper){
    Mono<Route> route = loadRoute(apiManagementWrapper.getEnterptiseContext(), loginCookie);
    if(route == null) {
        return;
    }
}


private Mono<Route> loadRoute(EnterpriseContext enterpriseContext, ResponseCookie loginCookie) {
    Mono<Route> route = this.webClientRouteConfirmation
            .get()
            .uri("http://localhost:8383/routes/search/findByServiceIdAndClientId?serviceName=" + enterpriseContext.getTarget() + "&clientName" + enterpriseContext.getSource())
            .cookie("JSESSION_ID", loginCookie.getValue())
            .exchange()
            .flatMap(clientResponse -> clientResponse.bodyToMono(Route.class));

    route.subscribe(r -> {
       handleRoute(enterpriseContext, loginCookie);
    });
}

使用'login()'方法，我可以获得'jsession_id'Cookie，但是当它返回一个Mono时，我不能访问Cookie值（我可以使用clientResponse.block()，但是我知道它很糟糕，所以尽量不要这样做），所以我尝试用回调订阅clientResponse，但是如果我尝试这样做，我将与'business service()'方法解耦，并且不能返回我喜欢的值······

所以作为伪代码，我想要实现的是....

@RequestMapping(value = "/endpoint1", method = RequestMethod.POST)
public Mono<String> businessService(@RequestBody ApiManagementWrapper apiManagementWrapper, ServerWebExchange httpRequest) {
    log.info("Handling /netty1");

    Route route = login(apiManagementWrapper);

    Mono<String> t = null;
    if(route != null) {
        t = fetch(apiManagementWrapper, httpRequest);
    }

    return t;
}

但是我不知道如何在不使用mono.block（）的情况下到达那里。

从'handle login()'返回'route'对象没有任何意义，因为如果我正确理解了反应概念，'fetch()'方法无论如何都不会等待它....

有什么提示吗？

Answer 1

可以在全球范围内应用的内容：

• 使方法返回反应类型，如mono 或flux
• 避免在web应用程序中使用subscribe，因为它将执行与当前请求/响应分离，并且不能保证任务的完成

然后可以使用可用的运算符组合这些反应类型。类似于：

Mono<LoginInformation> login = doLogin();
Mono<String> value = login.flatMap(info -> callRemoteService(info));