How to extract response header & status code from Spring 5 WebClient ClientResponse

问题

I am new to Spring Reactive framework & trying to convert Springboot 1.5.x code into Springboot 2.0. I need to return response header after some filtering, body & status code from Spring 5 WebClient ClientResponse. I do not want to use block() method as it will convert it into sync call. I am able to get responsebody pretty easily using bodyToMono. Also, I am getting status code, headers & body if I am just returning ClientResponse but I need to process response based on statusCode & header parameters. I tried subscribe, flatMap etc. but nothing works.

E.g. - Below code will return response Body

Mono<String> responseBody =  response.flatMap(resp -> resp.bodyToMono(String.class));

But similar paradigm is not working to get statusCode & Response headers. Can someone help me in extracting statusCode & header parameters using Spring 5 reactive framework.

回答1:

You can use the exchange function of webclient e.g.

Mono<String> reponse = webclient.get()
.uri("https://stackoverflow.com")
.exchange()
.doOnSuccess(clientResponse -> System.out.println("clientResponse.headers() = " + clientResponse.headers()))
.doOnSuccess(clientResponse -> System.out.println("clientResponse.statusCode() = " + clientResponse.statusCode()))
.flatMap(clientResponse -> clientResponse.bodyToMono(String.class));

then you can convert bodyToMono etc

回答2:

I needed to check the response details(headers, status, etc) and body as well.

The only way I was able to do it was by using .exchange() with two subscribe() as the following example:

    Mono<ClientResponse> clientResponse = WebClient.builder().build()
            .get().uri("https://stackoverflow.com")
            .exchange();

    clientResponse.subscribe((response) -> {

        // here you can access headers and status code
        Headers headers = response.headers();
        HttpStatus stausCode = response.statusCode();

        Mono<String> bodyToMono = response.bodyToMono(String.class);
        // the second subscribe to access the body
        bodyToMono.subscribe((body) -> {

            // here you can access the body
            System.out.println("body:" + body);

            // and you can also access headers and status code if you need
            System.out.println("headers:" + headers.asHttpHeaders());
            System.out.println("stausCode:" + stausCode);

        }, (ex) -> {
            // handle error
        });
    }, (ex) -> {
        // handle network error
    });

I hope it helps. If someone knows a better way to do it, please let us know.

回答3:

You can configure spring boot >= 2.1.0 to log request and response if you are using the WebClient:

spring.http.log-request-details: true
logging.level.org.springframework.web.reactive.function.client.ExchangeFunctions: TRACE

As desribed in the sprint boot docs, if you want headers to be logged, too, you have to add

Consumer<ClientCodecConfigurer> consumer = configurer ->
    configurer.defaultCodecs().enableLoggingRequestDetails(true);

WebClient webClient = WebClient.builder()
    .exchangeStrategies(ExchangeStrategies.builder().codecs(consumer).build())
    .build();

But be aware that this can log sensitve information.

回答4:

For status code you can try this:

Mono<HttpStatus> status = webClient.get()
                .uri("/example")
                .exchange()
                .map(response -> response.statusCode());

For headers:

Mono<HttpHeaders> result = webClient.get()
                .uri("/example")
                .exchange()
                .map(response -> response.headers().asHttpHeaders());

来源：https://stackoverflow.com/questions/50223891/how-to-extract-response-header-status-code-from-spring-5-webclient-clientrespo

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