Reactive Advice

Starting with version 5.3, a ReactiveRequestHandlerAdvice can be used for request message handlers producing a Mono replies. A BiFunction<Message<?>, Mono<?>, Publisher<?>> has to be provided for this advice and it is called from the Mono.transform() operator on a reply produced by the intercepted handleRequestMessage() method implementation. Typically, such a Mono customization is necessary when we would like to control network fluctuations via timeout(), retry() and similar support operators. For example when we can an HTTP request over WebFlux client, we could use below configuration to not wait for response more than 5 seconds:

The message argument is the request message for the message handler and can be used to determine request-scope attributes. The mono argument is the result of this message handler’s handleRequestMessage() method implementation. A nested Mono.transform() can also be called from this function to apply, for example, a Reactive Circuit Breaker.