Cache the result of a Mono from a WebClient call in a Spring WebFlux web application

Question

I am looking to cache a Mono (only if it is successful) which is the result of a WebClient call.

From reading the project reactor addons docs I don\'t

Answer 1

Actually, you don't have to save errors with CacheMono.

private Cache myCaffeineCache;

...

Mono myResponseObject =
        CacheMono.lookup(key -> Mono.justOrEmpty(myCaffeineCache.getIfPresent(key))
                .map(Signal::next), myRequestObject)
                .onCacheMissResume(() -> /* Your web client or other Mono here */)
                .andWriteWith((key, signal) -> Mono.fromRunnable(() ->
                        Optional.ofNullable(signal.get())
                                .ifPresent(value -> myCaffeineCache.put(key, value))));

When you switch to external cache, this may be usefull. Don't forget using reactive clients for external caches.