Accessing the response body with Spring WebFlux WebClient with onStatus
While writing some integration tests for a WebClient today, I wanted to take advantage of the onStatus method to perform some operational logging using the response body, before I mapped it to a particular exception.
I found it really quite difficult to do, as I wanted to use .block(), but found it didn't work, and other means I'd tried just ended up not executing.
I found that the following ended up working:
import org.junit.jupiter.api.Test;
import org.slf4j.LoggerFactory;
import org.springframework.http.HttpStatus;
import org.springframework.web.reactive.function.client.WebClient;
class Example {
@Test
void example() {
WebClient webClient = WebClient.builder().build();
webClient
.get()
.uri("http://localhost:4010/")
.retrieve()
.onStatus(
s -> s.equals(HttpStatus.NOT_FOUND),
(e) ->
e.bodyToMono(ErrorResponse.class)
.handle(
(body, handler) -> {
LoggerFactory.getLogger(getClass()).warn("HTTP 404 returned: {}", body);
handler.error(new BusinessLogicException());
}))
.toBodilessEntity()
.block();
}
private static class BusinessLogicException extends Exception {}
private record ErrorResponse(String type, String title, long status, String detail) {}
}
This use of handle allows it to process asynchronously, giving us the chance to interact with the parsed response body.
