How to retry in the new HTTP interface in Spring 6 and Spring Boot 3

Spring has introduced the new HTTP interface. For exception handling the documentation states to register a response status handler that applies to all responses performed through the client:

WebClient webClient = WebClient.builder()
    .defaultStatusHandler(HttpStatusCode::isError, resp -> ...)
    .build();

However, it's not clear how to handle retries.

In WebClient you could simple use retryWhen():

public Mono<String> getData(String stockId) {
return webClient.get()
  .uri(PATH_BY_ID, stockId)
  .retrieve()
  .bodyToMono(String.class)
  .retryWhen(Retry.backoff(3, Duration.ofSeconds(2)));
}

I'm not sure how to incorporate retries with the Http interfaces.

I figured it out. You need to use an exchange filter. I implemented a similiar solution for a different problem: Adding a retry all requests of WebClient

 @Bean
  TodoClient todoClient() {
    WebClient webClient =
        WebClient.builder()
            .baseUrl("sampleUrl")
            .filter(retryFilter())
            .build();
    HttpServiceProxyFactory factory =
        HttpServiceProxyFactory.builder(WebClientAdapter.forClient(webClient)).build();
    return factory.createClient(TodoClient.class);
  }

  
private ExchangeFilterFunction retryFilter() {
return (request, next) ->
    next.exchange(request)
        .flatMap(clientResponse ->
            Mono.just(clientResponse)
                .filter(response -> clientResponse.statusCode().isError())
                .flatMap(ClientResponse::createException)
                .flatMap(Mono::error)
                .thenReturn(clientResponse)
        )
        .retryWhen(
            Retry.fixedDelay(3, Duration.ofSeconds(30))
                .doAfterRetry(retrySignal -> log.warn("Retrying"))
        );

}