I am using webflux Mono (in Spring boot 5) to consume an external API. I am able to get data well when the API response status code is 200, but when the API returns an error I am not able to retrieve the error message from the API. Spring webclient error handler always display the message as
ClientResponse has erroneous status code: 500 Internal Server Error
, but when I use PostMan the API returns this JSON response with status code 500.
{
"error": {
"statusCode": 500,
"name": "Error",
"message":"Failed to add object with ID:900 as the object exists",
"stack":"some long message"
}
}
My request using WebClient is as follows
webClient.getWebClient()
.post()
.uri("/api/Card")
.body(BodyInserters.fromObject(cardObject))
.retrieve()
.bodyToMono(String.class)
.doOnSuccess( args -> {
System.out.println(args.toString());
})
.doOnError( e ->{
e.printStackTrace();
System.out.println("Some Error Happend :"+e);
});
My question is, how can I get access to the JSON response when the API returns an Error with status code of 500?
If you want to retrieve the error details:
WebClient webClient = WebClient.builder()
.filter(ExchangeFilterFunction.ofResponseProcessor(clientResponse -> {
if (clientResponse.statusCode().isError()) {
return clientResponse.bodyToMono(ErrorDetails.class)
.flatMap(errorDetails -> Mono.error(new CustomClientException(clientResponse.statusCode(), errorDetails)));
}
return Mono.just(clientResponse);
}))
.build();
with
class CustomClientException extends WebClientException {
private final HttpStatus status;
private final ErrorDetails details;
CustomClientException(HttpStatus status, ErrorDetails details) {
super(status.getReasonPhrase());
this.status = status;
this.details = details;
}
public HttpStatus getStatus() {
return status;
}
public ErrorDetails getDetails() {
return details;
}
}
and with the ErrorDetails
class mapping the error body
Per-request variant:
webClient.get()
.exchange()
.map(clientResponse -> {
if (clientResponse.statusCode().isError()) {
return clientResponse.bodyToMono(ErrorDetails.class)
.flatMap(errorDetails -> Mono.error(new CustomClientException(clientResponse.statusCode(), errorDetails)));
}
return clientResponse;
})