如何在Spring WebClient中拦截http流量？

Question

如何在WebFilter请求从DTO转换为JSON字符串之后拦截它们？

WebClient.builder().defaultHeader(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE).filter(logRequest()).build();

private ExchangeFilterFunction logRequest() {
    return ExchangeFilterFunction.ofRequestProcessor(clientRequest -> {
        LOGGER.info(clientRequest.body()); //body is MyRequest.class
        return Mono.just(clientRequest);
    });
}

MyRequestDto dto;
client.post().uri(url).syncBody(dto).retrieve().bodyToMono(MyResponseDto.class).block();

反过来，在响应从JSON转换为dto之前拦截它们。

Answer 1

JacksonEncoder在Databuffer中以字符串而不是字节的形式写入数据。截获请求的一种方法是重写JSON编码器，直接访问DataBuffer或将其解释为字符串。

Consumer<ClientCodecConfigurer> consumer = configurer ->
        configurer.defaultCodecs().jackson2JsonEncoder(new Jackson2JsonEncoder() {
            @Override
            public Flux<DataBuffer> encode(Publisher<?> inputStream, DataBufferFactory bufferFactory, ResolvableType elementType, @Nullable MimeType mimeType, @Nullable Map<String, Object> hints) {
                return super.encode(inputStream, bufferFactory, elementType, mimeType, hints)
                        .doOnNext(dataBuffer -> System.out.println(StandardCharsets.UTF_8.decode(dataBuffer.asByteBuffer()).toString()));
            }
        });

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

如果目的只是记录传出的消息正文，请参见以下问题：如何记录Spring 5 WebClient调用