NetworkingClient problem when handle response from CF security server

[lavcraft]

Configure context with Network Client for cloudfoundry:

    @Bean
    DefaultConnectionContext connectionContext(CloudFoundryProperties cloudFoundryProperties) {
        return DefaultConnectionContext.builder()
                .apiHost(cloudFoundryProperties.getApiHost())
                .skipSslValidation(true)
                .cacheDuration(Duration.ofSeconds(cloudFoundryProperties.getClientCacheInSeconds()))
                .keepAlive(true)
                .build();
    }

    @Bean
    public ClientCredentialsGrantTokenProvider refreshTokenGrantTokenProvider(MetricsBrokerProperties metricsBrokerProperties) {
        return ClientCredentialsGrantTokenProvider.builder()
                .clientId(metricsBrokerProperties.getClientId())
                .clientSecret(metricsBrokerProperties.getClientSecret())
                .build();
    }

    @Bean
    public NetworkingClient networkingClient(ConnectionContext connectionContext,
                                             TokenProvider tokenProvider) {
        return ReactorNetworkingClient.builder()
                .connectionContext(connectionContext)
                .tokenProvider(tokenProvider)
                .build();
    }

And try it in next example:

@Service
@RequiredArgsConstructor
public class CFPolicyService implements PolicyService {
    private final NetworkingClient networkingClient;

    @Override
    public void allowConnection(String sourceId, String destId, List<Pair<String, Integer>> protocols) {
        networkingClient.policies()
                .create(CreatePoliciesRequest.builder()
                        .policies(createPolicies(sourceId, destId, protocols))
                        .build())
                .retry(3)
                .onErrorContinue((throwable, o) -> {
                    log.error("Sth went wrong with message: {}", throwable.getMessage());
                    if(o instanceof byte[]) {
                        byte[] byteData = (byte[]) o;
                        log.error("Data: {}", new String(byteData));
                    }
                })
                .block(Duration.ofSeconds(20));

        log.debug("Policy from {} to {} for protocols {} created", sourceId, destId, protocols);
    }
...

After run policies request I saw next error:

   2019-07-10T10:58:19.97+0300 [APP/PROC/WEB/0] OUT 2019-07-10 07:58:19.973 ERROR 9 --- [ry-client-nio-3] o.s.c.s.metrics.service.CFPolicyService  : Sth went wrong with message: The mapper returned a null value.
   2019-07-10T10:58:19.97+0300 [APP/PROC/WEB/0] OUT 2019-07-10 07:58:19.973 ERROR 9 --- [ry-client-nio-3] o.s.c.s.metrics.service.CFPolicyService  : Data: {}

2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR java.lang.NullPointerException: The mapper returned a null value.
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at java.util.Objects.requireNonNull(Objects.java:228)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:100)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.core.publisher.FluxMap$MapSubscriber.onNext(FluxMap.java:114)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.channel.FluxReceive.drainReceiver(FluxReceive.java:213)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.channel.FluxReceive.onInboundNext(FluxReceive.java:329)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.channel.ChannelOperations.onInboundNext(ChannelOperations.java:311)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.http.client.HttpClientOperations.onInboundNext(HttpClientOperations.java:628)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.channel.ChannelOperationsHandler.channelRead(ChannelOperationsHandler.java:138)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.http.HttpOperations.lambda$static$2(HttpOperations.java:280)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at reactor.ipc.netty.ReactorNetty$ExtractorHandler.channelRead(ReactorNetty.java:366)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:102)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:438)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:323)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:297)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.CombinedChannelDuplexHandler.channelRead(CombinedChannelDuplexHandler.java:253)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.ssl.SslHandler.unwrap(SslHandler.java:1478)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.ssl.SslHandler.decodeJdkCompatible(SslHandler.java:1227)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.ssl.SslHandler.decode(SslHandler.java:1274)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.decodeRemovalReentryProtection(ByteToMessageDecoder.java:502)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.callDecode(ByteToMessageDecoder.java:441)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:278)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:352)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1408)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:374)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:360)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:930)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:163)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:682)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:617)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:534)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:906)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
   2019-07-10T11:34:14.57+0300 [APP/PROC/WEB/0] ERR     at java.lang.Thread.run(Thread.java:748)

Mapper really returns null. I guess it is bug, because try to handle Mono, but api return empty json {}.

[GFriedrich]

I ran into the same issue. Looks like that in contrast to the regular API, the networking API returns an empty JSON object (aka "{}") and HTTP code 200 (the Cloud Foundry API uses code 204 and therefore no response content at all).
This in turn results in the object mapper being called at

cf-java-client/cloudfoundry-client-reactor/src/main/java/org/cloudfoundry/reactor/util/JsonCodec.java

Line 49 in 25fac55

return objectMapper.readValue(payload, responseType);

As the target type is set to "Void" it will always return "null" - which is the regular behaviour for Jackson's objectmapper class.

@twoseat Would you mind if I fix this issue in a PR?

[twoseat]

@GFriedrich Please do!