Issue with chaining web requests.

[JarlDue]

I am working with Quarkus and their reactive rest client, and trying to do something that to me appears quite simple, but somehow it's not working the way I expected it to.

I looked at the example here uni-transforming-an-item-into-a-uni

Uni<String> uni = Uni.createFrom().item("Cameron");
uni
    .onItem().transformToUni(name -> invokeRemoteGreetingService(name))
    .subscribe().with(
            item -> System.out.println(item), // Print "Hello Cameron",
            fail -> fail.printStackTrace()); // Print the failure stack trace

This seems very straight forward, to get into more detail, I am trying to call a webservice, and then when it replies, call another service using the value of it's reply.

` Uni otlLink = oneTimeLinksAdapter.createOneTimeLink(finalUrl);

    Uni<String> stringUni = Uni.createFrom().item("Hello");

    //This fails
    otlLink
            .onItem()
            .transformToUni(communicationsAdapter::sendMessage)
            .subscribe()
            .with(i -> System.out.println("Message: " + i), Throwable::printStackTrace);


    //This works
    communicationsAdapter.sendMessage("Hello 1")
            .subscribe()
            .with(i -> System.out.println("Message: " + i), Throwable::printStackTrace);

    //This also works
    stringUni
            .onItem()
            .transformToUni(communicationsAdapter::sendMessage)
            .subscribe()
            .with(i -> System.out.println("Message: " + i), Throwable::printStackTrace);`

It works when I do not try to chain them, it even works if I manually enter the value, but that's obviously not very useful.

I get the following error.

java.lang.NullPointerException: Cannot invoke "Object.getClass()" because "obj" is null
	at org.jboss.resteasy.reactive.common.headers.HeaderUtil.headerToString(HeaderUtil.java:45)
	at org.jboss.resteasy.reactive.client.impl.ClientRequestHeaders.asMap(ClientRequestHeaders.java:157)
	at org.jboss.resteasy.reactive.client.handlers.ClientSendRequestHandler.setRequestHeadersAndPrepareBody(ClientSendRequestHandler.java:508)
	at org.jboss.resteasy.reactive.client.handlers.ClientSendRequestHandler$2.accept(ClientSendRequestHandler.java:188)
	at org.jboss.resteasy.reactive.client.handlers.ClientSendRequestHandler$2.accept(ClientSendRequestHandler.java:112)
	at io.smallrye.context.impl.wrappers.SlowContextualConsumer.accept(SlowContextualConsumer.java:21)
	at io.smallrye.mutiny.helpers.UniCallbackSubscriber.onItem(UniCallbackSubscriber.java:77)
	at io.smallrye.mutiny.operators.uni.UniOperatorProcessor.onItem(UniOperatorProcessor.java:46)

I also get this.

12:13:14 ERROR traceId=, parentId=, spanId=, sampled= [io.ve.co.ne.im.ConnectionBase] (vert.x-eventloop-thread-3) Received HTTP message with no request in progress
12:13:14 ERROR traceId=, parentId=, spanId=, sampled= [io.ve.co.ht.im.HttpClientRequestImpl] (vert.x-eventloop-thread-3) Received HTTP message with no request in progress
12:13:14 ERROR traceId=, parentId=, spanId=, sampled= [io.ve.co.ne.im.ConnectionBase] (vert.x-eventloop-thread-3) Received HTTP message with no request in progress

[jponge]

Do you have any reproducer? It's a bit hard to guess types and what methods do.

[JarlDue]

While building the reproducer, I stumbled upon why it was not working.

A CorrelationIdFilter had recently been added and this was causing the issue.

import org.slf4j.MDC;

import javax.enterprise.context.RequestScoped;
import javax.ws.rs.client.ClientRequestContext;
import javax.ws.rs.client.ClientRequestFilter;
import javax.ws.rs.ext.Provider;

import static configuration.correlation.CorrelationIdFilter.CORRELATION_ID_HEADER;

@Provider
@RequestScoped
public class CorrelationIdClientFilter implements ClientRequestFilter {
    @Override
    public void filter(ClientRequestContext requestContext) {
        String correlationIdHeader = MDC.get(CORRELATION_ID_HEADER);
        requestContext.getHeaders().add(CORRELATION_ID_HEADER, correlationIdHeader);
    }
}

This was causing the issue, after removing it, everything worked as expected.