How to chain reactive calls correctly and sequentially

Question

I am trying to make calls with the following order:

1. save an object

2. publish an object creation event, only if the first step is done

3. Return a Flux list What I have currently is following:

   return dbSaveObject(object) //this returns Mono of created object
       .doOnSuccess(s -> hermes.publishEvent(CREATE)) //publishEvent() here returns Mono<Void>
       .thenMany(Flux.just(object))
   

Would this work and publish event as requested, or should I use zipWhen() instead of doOnSuccess()?

Answer 1

doOn... are so-called side-effect operators and should not be used for constructing reactive flows.

In case publishEvent returns Mono<Void> you could use the following

return dbSaveObject(object)
        .flatMap(savedObject ->
                hermes.publishEvent(CREATE)
                        .thenReturn(savedObject)
        );