reactor.core.Exceptions$ErrorCallbackNotImplemented: io.modelcontextprotocol.spec.McpError: Received unrecognized SSE event type: null #93
Description
2025-04-01 08:40:34,831 - sse_starlette.sse - DEBUG - ping: b': ping - 2025-04-01 00:40:34.831535+00:00\r\n\r\n'
2025-04-01 08:40:38,680 - sse_starlette.sse - DEBUG - ping: b': ping - 2025-04-01 00:40:38.679807+00:00\r\n\r\n'
@Override
public Mono<Void> connect(Function<Mono<JSONRPCMessage>, Mono<JSONRPCMessage>> handler) {
Flux<ServerSentEvent<String>> events = eventStream();
this.inboundSubscription = events.concatMap(event -> Mono.just(event).<JSONRPCMessage>handle((e, s) -> {
if (ENDPOINT_EVENT_TYPE.equals(event.event())) {
String messageEndpointUri = event.data();
if (messageEndpointSink.tryEmitValue(messageEndpointUri).isSuccess()) {
s.complete();
}
else {
// TODO: clarify with the spec if multiple events can be
// received
s.error(new McpError("Failed to handle SSE endpoint event"));
}
}
else if (MESSAGE_EVENT_TYPE.equals(event.event())) {
try {
JSONRPCMessage message = McpSchema.deserializeJsonRpcMessage(this.objectMapper, event.data());
s.next(message);
}
catch (IOException ioException) {
s.error(ioException);
}
}
else {
s.error(new McpError("Received unrecognized SSE event type: " + event.event()));
}
}).transform(handler)).subscribe();reactor.core.Exceptions$ErrorCallbackNotImplemented: io.modelcontextprotocol.spec.McpError: Received unrecognized SSE event type: null
Caused by: io.modelcontextprotocol.spec.McpError: Received unrecognized SSE event type: null
at io.modelcontextprotocol.client.transport.WebFluxSseClientTransport.lambda$connect$0(WebFluxSseClientTransport.java:194) ~[mcp-spring-webflux-0.8.1.jar:0.8.1]
at reactor.core.publisher.FluxHandleFuseable$HandleFuseableSubscriber.onNext(FluxHandleFuseable.java:179) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.Operators$ScalarSubscription.request(Operators.java:2571) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxHandleFuseable$HandleFuseableSubscriber.request(FluxHandleFuseable.java:260) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.request(FluxPeekFuseable.java:144) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2367) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.onSubscribe(Operators.java:2241) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableSubscriber.onSubscribe(FluxPeekFuseable.java:178) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxHandleFuseable$HandleFuseableSubscriber.onSubscribe(FluxHandleFuseable.java:164) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.MonoJust.subscribe(MonoJust.java:55) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.Mono.subscribe(Mono.java:4576) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onNext(FluxConcatMapNoPrefetch.java:207) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.SerializedSubscriber.onNext(SerializedSubscriber.java:99) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxRetryWhen$RetryWhenMainSubscriber.onNext(FluxRetryWhen.java:178) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.MonoFlatMapMany$FlatMapManyInner.onNext(MonoFlatMapMany.java:251) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxOnErrorResume$ResumeSubscriber.onNext(FluxOnErrorResume.java:79) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxOnAssembly$OnAssemblySubscriber.onNext(FluxOnAssembly.java:539) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.innerNext(FluxConcatMapNoPrefetch.java:259) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatMap$ConcatMapInner.onNext(FluxConcatMap.java:865) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatMap$WeakScalarSubscription.request(FluxConcatMap.java:480) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.Operators$MultiSubscriptionSubscriber.set(Operators.java:2367) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatMapNoPrefetch$FluxConcatMapNoPrefetchSubscriber.onNext(FluxConcatMapNoPrefetch.java:202) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxBufferPredicate$BufferPredicateSubscriber.onNextNewBuffer(FluxBufferPredicate.java:317) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxBufferPredicate$BufferPredicateSubscriber.tryOnNext(FluxBufferPredicate.java:227) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxBufferPredicate$BufferPredicateSubscriber.onNext(FluxBufferPredicate.java:200) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxPeekFuseable$PeekFuseableConditionalSubscriber.onNext(FluxPeekFuseable.java:503) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:299) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxDoFinally$DoFinallySubscriber.onNext(FluxDoFinally.java:113) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxConcatArray$ConcatArraySubscriber.onNext(FluxConcatArray.java:180) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drainAsync(FluxFlattenIterable.java:453) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drain(FluxFlattenIterable.java:724) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.onNext(FluxFlattenIterable.java:256) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxPublish$PublishSubscriber.drain(FluxPublish.java:571) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxPublish$PublishSubscriber.onNext(FluxPublish.java:310) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxContextWrite$ContextWriteSubscriber.onNext(FluxContextWrite.java:107) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxMapFuseable$MapFuseableConditionalSubscriber.onNext(FluxMapFuseable.java:299) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drainAsync(FluxFlattenIterable.java:453) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.drain(FluxFlattenIterable.java:724) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.core.publisher.FluxFlattenIterable$FlattenIterableSubscriber.onNext(FluxFlattenIterable.java:256) ~[reactor-core-3.7.3.jar:3.7.3]
at reactor.adapter.JdkFlowAdapter$SubscriberToRS.onNext(JdkFlowAdapter.java:150) ~[reactor-core-3.7.3.jar:3.7.3]
at java.net.http/jdk.internal.net.http.ResponseSubscribers$PublishingBodySubscriber.onNext(ResponseSubscribers.java:1003) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.ResponseSubscribers$PublishingBodySubscriber.onNext(ResponseSubscribers.java:843) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:382) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$Http1BodySubscriber.onNext(Http1Response.java:297) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:229) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.ResponseContent$ChunkedBodyParser.accept(ResponseContent.java:129) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:790) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.handle(Http1Response.java:720) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$Receiver.accept(Http1Response.java:612) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1Response$BodyReader.tryAsyncReceive(Http1Response.java:750) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.Http1AsyncReceiver.flush(Http1AsyncReceiver.java:233) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:205) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149) ~[java.net.http:na]
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:230) ~[java.net.http:na]
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136) ~[na:na]
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635) ~[na:na]
at java.base/java.lang.Thread.run(Thread.java:833) ~[na:na]