This will show how to access the webservice message when a error occurs during a webservice call.
When you make a webservice call in your code you usually process the response functionally in a map and have a onErrorResume handler to handle the call failure. The following is an example of a http call in a Spring Reactive stack with error handler:
1. final String endpoint = localHost+"/api/health/throwerror";
2. WebClient.ResponseSpec responseSpec = webClient.get().uri(endpoint).accept(MediaType.APPLICATION_JSON).retrieve();
3. return responseSpec.bodyToMono(Map.class).
flatMap(s ->
ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
.bodyValue(getMap(Pair.of("message", s.toString()))))
.onErrorResume(throwable -> {
LOG.error("endpoint: '{}' rest call failed: {}", endpoint, throwable.getMessage());
String errorMessage = throwable.getMessage();
4. if (throwable instanceof WebClientResponseException) {
WebClientResponseException webClientResponseException = (WebClientResponseException) throwable;
LOG.error("error body contains: {}", webClientResponseException.getResponseBodyAsString());
errorMessage = webClientResponseException.getResponseBodyAsString();
}
return Mono.error(new SecurityException(errorMessage));
});
In the event of a error when a webservice call is made you would have to cast the Throwable object into a WebClientResponseException class to get the actual webservice message. In the above example, you can see the throwable object is casted to a WebClientResponseException to get the actual mesage. For an example of this usage you can follow this example from the jwt-validator project.
The example I have shown is from a test case. In this example, the proxied service returns a bad request or http 400 error invoking onErrorResume block in the caller code. I print both the thorwable.getMessage() vs the webClientResponseException.getResponseBodyAsString() output to show the output.
When I run the test case, the proxied error http message is captured here:
EndpointHandler : throwing error
2023-04-03 10:41:14.484 ERROR 60979 --- EndpointHandler : endpoint: 'http://localhost:10001/api/health/throwerror' rest call failed: 400 Bad Request from GET http://localhost:10001/api/health/throwerror
2023-04-03 10:41:14.484 ERROR 60979 --- EndpointHandler : error body contains: throwing error
testImplementation (‘org.springframework.boot:spring-boot-starter-test’) { exclude (group: ‘com.vaadin.external.google’, module: ‘android-json’) }