Spring reactive webClient - how to call methods on a Mono

Question

New to reactive programming and trying to create a reactive service via WebFlux and WebClient.

The flow of the method is like

1. POST request and wait for response back
2. Body of response to a mapping service (which has some other business logic) and which returns a Recommendations type
3. Create a ResponseEntity
4. Create a Mono of type Mono<ResponseEntity>

Question is this a valid of way doing this as in should I be using .exchange()? and is there a way of chaining these methods instead of individual methods

current implementation:

private Mono<ResponseEntity<Recommendations>> myMethod(final Request request, final String variantName) {

    Mono<String> response = webClient.build()
            .post()
            .uri(uri)
            .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
            .header(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE)
            .bodyValue(requestBody)
            .retrieve().bodyToMono(String.class);

    var recommendations = ((XYZResponseMapper) responseMapper).mapReactive(request, response, useCaseId, variantName); //return type Recommendations
    var entity = new ResponseEntity<>(recommendations, nullHeaders, HttpStatus.OK);
    return Mono.just(entity);

}

Answer 1

After a lot of reading and experimenting I managed to make it work with the following:

    return webClient.build()
            .post()
            .uri(uri)
            .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON_VALUE)
            .header(HttpHeaders.ACCEPT, MediaType.APPLICATION_JSON_VALUE)
            .bodyValue(requestBody)
            .retrieve()
            .toEntity(String.class)
            .publishOn(Schedulers.boundedElastic())
            .map(x -> {
           
                var recs = processResponse(request, x.getBody(), useCaseId, variantName);
                return new ResponseEntity<GatewayRecommendations>(recs, x.getStatusCode());
            });