WebClient Request and Response body logging

Question

I am trying to make a POJO out of request and response data received when making WebClient calls. But I am not getting the request body in string/JSON readable form instead I am getting a BodyInsertor. I am making use of Exchange Filters.

public ExchangeFilterFunction logWebRequest() {
    return (request, next) -> {
      log.info("Entered in logWebRequest for WebClient");
      long startTime = System.currentTimeMillis();
      Mono<ClientResponse> response = next.exchange(request);
      long processingTimeInMs = System.currentTimeMillis() - startTime;

      // request.body() -> Gives Body Insertor

      WebRequestLog webRequestLog = webRequestService.makeWebRequestLog(request, response.block());
      webRequestLog.setProcessingTimeInMs(processingTimeInMs);

      log.info("WebRequest to be produced to kafka topic: " + webRequestLog);
      kafkaService.produceAuditLog(webRequestLog);
      return response;
    };
  }

I followed some articles such as https://andrew-flower.com/blog/webclient-body-logging and https://www.gitmemory.com/issue/spring-projects/spring-framework/24262/570245788 but nothing worked for me.

My end goal is to capture requests and responses with their bodies and produce the data collected for Kafka.

Your problems is fully not related to Spring Kafka. Please, be careful when you choose tags for your question. — Artem Bilan, Apr 28 '21 at 13:56

score 0 · Answer 1 · answered Apr 28 '21 at 14:23

Inside ExchangeFilterFunction, you can access HTTP method, URL, headers, cookies but request or response body can not be accessed directly from this filter.

Refer to the answer here. It provides a way to get access to the request and response body. It also provides a link to This blog post. It explains how to get the body in JSON/String format in Web Client.

score 0 · Answer 2 · answered Feb 03 '22 at 22:29

You can do tracing of request and response payloads with small manipulations with request and responses:

public class TracingExchangeFilterFunction implements ExchangeFilterFunction {
 
 
        return next.exchange(buildTraceableRequest(request))
                .flatMap(response ->
                        response.body(BodyExtractors.toDataBuffers())
                                .next()
                                .doOnNext(dataBuffer -> traceResponse(response, dataBuffer))
                                .thenReturn(response)) ;
    }

    private ClientRequest buildTraceableRequest( 
            final ClientRequest clientRequest) {
        return ClientRequest.from(clientRequest).body(
                new BodyInserter<>() {
                    @Override
                    public Mono<Void> insert(
                            final ClientHttpRequest outputMessage,
                            final Context context) {
                        return clientRequest.body().insert(
                                new ClientHttpRequestDecorator(outputMessage) {
                                    @Override
                                    public Mono<Void> writeWith(final Publisher<? extends DataBuffer> body) {
                                        return super.writeWith(
                                                from(body).doOnNext(buffer ->
                                                        traceRequest(clientRequest, buffer)));
                                    }
                                }, context);
                    }
                }).build();
    }

    private void traceRequest(ClientRequest clientRequest, DataBuffer buffer) {
        final ByteBuf byteBuf = NettyDataBufferFactory.toByteBuf(buffer);
        final byte[] bytes = ByteBufUtil.getBytes(byteBuf);
        // do some tracing e.g. new String(bytes)
    }


    private void traceResponse(ClientResponse response, DataBuffer dataBuffer) {
        final byte[] bytes = new byte[dataBuffer.readableByteCount()];
        dataBuffer.read(bytes);
        // do some tracing e.g. new String(bytes)
    }
}

WebClient Request and Response body logging

2 Answers2