im working ins Spring web flux project and I used functional endpoints instead of controller annotation but I didn't find a solution to handle multiple exceptions for the same endpoint , this is my code :
#Override
protected RouterFunction<ServerResponse> getRoutingFunction(ErrorAttributes errorAttributes) {
return RouterFunctions.route(RequestPredicates.GET("/router/users/{id}"),this::renderException);
}
private Mono<ServerResponse> renderException(ServerRequest request) {
Map<String, Object> error = this.getErrorAttributes(request, ErrorAttributeOptions.defaults());
error.remove("status");
error.remove("requestId");
return ServerResponse.status(HttpStatus.BAD_REQUEST).contentType(MediaType.APPLICATION_JSON)
.body(BodyInserters.fromValue(error));
}
for the endpoint /router/users/{id} i trigger UserNotFoundException and UserException and I want to return 404 for UserNotFoundException and 500 for UserException but I don't know how to do that in the functional endpoint. anyone can guide me on how to do this in the correct way like we did in using #ExceptionHandler in rest controller?
If returning proper code is all you care about then adding #ResponseStatus for your custom exceptions might be the best solution.
#ResponseStatus(HttpStatus.NOT_FOUND)
public class UserNotFoundException extends RuntimeException {
// more methods...
public UserNotFoundException(final String message) {
super(message);
}
}
But if you want to build ServerResponse by yourself, make use of project reactor operators, like switchIfEmpty() or onErrorMap(), etc. which could be used as following
Mono<ServerResponse> response() {
return exampleService.getUser()
.flatMap(user -> ServerResponse.ok().body(user, User.class))
.switchIfEmpty(ServerResponse.notFound().build());
}
You might want to take a look at docs Which operator do I need? - handling errors
Related
I'am writing a complex application as an experiment with Spring 5 Webflux. I'm planning to use lot's of techniques in this application. I'm familiar with the "old style" #RestController, but now, I'm writing functional endpoints. E.g. the backend of a company registration service.I was after something like the #ControllerAdvice in the "old world". But I wasn't really able to find anything similar as a reactive equivalent. (Or anything what worked out for me.)
I have a very basic setup. A routing function, a reactive Cassandra repository, a handler and a test class. The repository operation can throw IllegalArgumentException, and I'd like to handle it by returning HTTP Status BadRequest to client. Just as an example of I'm capable to do it. :-) The exception is taken care by the handler class. Here is my code.
RouterConfig
#Slf4j
#Configuration
#EnableWebFlux
public class RouterConfig {
#Bean
public RouterFunction<ServerResponse> route(#Autowired CompanyHandler handler) {
return RouterFunctions.route()
.nest(path("/company"), bc -> bc
.GET("/{id}", handler::handleGetCompanyDataRequest)
.before(request -> {
log.info("Request={} has been received.", request.toString());
return request;
})
.after((request, response) -> {
log.info("Response={} has been sent.", response.toString());
return response;
}))
.build();
}
}
CompanyHandler
#Slf4j
#Component
public class CompanyHandler {
#Autowired
private ReactiveCompanyRepository repository;
// Handle get single company data request
public Mono<ServerResponse> handleGetCompanyDataRequest(ServerRequest request) {
//Some validation ges here
return repository.findById(Mono.just(uuid))
.flatMap(this::ok)
.onErrorResume(IllegalArgumentException.class, e -> ServerResponse.badRequest().build())
.switchIfEmpty(ServerResponse.notFound().build());
}
private Mono<ServerResponse> ok (Company c) {
return ServerResponse.ok().contentType(MediaType.APPLICATION_JSON)
.body(BodyInserters.fromPublisher(Mono.just(c), Company.class));
}
}
ReactiveCompanyRepository
#Component
public interface ReactiveCompanyRepository extends ReactiveCassandraRepository<Company, UUID>{
Mono<Company> findByName(String name);
Mono<Company> findByEmail(String email);
}
My problem is that .onErrorResume(IllegalArgumentException.class, e -> ServerResponse.badRequest().build()) is never called and in the test case:
#SuppressWarnings("unchecked")
#Test
public void testGetCompanyExceptionDuringFind() {
Mockito.when(repository.findById(Mockito.any(Mono.class))).thenThrow(new IllegalArgumentException("Hahaha"));
WebTestClient.bindToRouterFunction(routerConfig.route(companyHandler))
.build()
.get().uri("/company/2b851f10-356e-11e9-a847-0f89e1aa5554")
.accept(MediaType.APPLICATION_JSON_UTF8)
.exchange()
.expectStatus().isBadRequest()
.returnResult(Company.class)
.getResponseBody();
}
I always get HttpStatus 500 instead of 400. So it fails.Any help would be appreciated!
Your test does not represent how a reactive API is supposed to behave. If such a repository throws an exception directly, I'd consider that a bug a report that to the maintainers.
When a reactive API returns a reactive type like Mono or Flux, it is expected that all errors are not thrown directly but actually sent as messages in the reactive pipeline.
In this case, your test case should probably be more like:
Mockito.when(repository.findById(Mockito.any(Mono.class)))
.thenReturn(Mono.error(new IllegalArgumentException("Hahaha")));
With that, the
onError... operators in Reactor will handle those error messages.
Need some small help about Spring Feign client. So here is the situation,
I have 2 Spring boot services. Let’s say Service A and Service B. I have configured my Service A with Feign client through which I call the Service B method.
So here is the code for my Service A,
My FeignCleint config interface,
#FeignClient(name = "FeignClient", url = "http://localhost:8081/ServiceB/hello")
public interface FeignApi {
#RequestMapping(method = RequestMethod.GET)
ResponseEntity<?> hello();
}
And my rest controller that uses above feign config to call the Service B method,
#RestController
public class ApiController {
#Autowired
private FeignApi feignApi;
#RequestMapping(value = "/callServiceB")
public ResponseEntity<?> companyInfo() {
ResponseEntity<?> response = new ResponseEntity("OK Response", HttpStatus.OK);
try {
response = feignApi.hello();
// Code for some other things related to application.
return response;
} catch (Exception ex) {
System.out.println("Service A Exception block reached.");
return new ResponseEntity(ex.getMessage(), HttpStatus.BAD_REQUEST);
}
}
}
below is my controller for Service B,
#RestController
public class MyController {
#GetMapping("/hello")
public String hello() throws Exception {
if (true) {
throw new Exception("Service B Exception...");
}
return "Hello World";
}
}
And my Controller advice to handle the exception that I am manually throwing,
#ControllerAdvice
public class MyControllerAdvice {
#ExceptionHandler
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
public ResponseEntity<?> handleException(Exception exception, Model model) {
return new ResponseEntity<>("Caused due to : " + exception.getMessage(), HttpStatus.INTERNAL_SERVER_ERROR);
}
}
Now my flow is like below,
As you can see, I am calling service B from service A using feign client. My service B is throwing an exception manually which I am catching using the controller advice and sending the exception details as an ResponseEntity back to the calling service A. So that Service A can process the details and move forward based on that.
The problem is when I hit the call from Service A using
http://localhost:8080/feign/callServiceB
The service B fails as expected. Now what I expect is that the Service A should receive the response back in form of the ResponseEntity. But what really happens is that the flow enters the exception block instead of staying in the try block. I can see this line printed,
"Service A Exception block reached."
This is what I don't understand. If I have managed the service B exception using controller advice and sent back the response to service A in form of ResponseEntity, then how come the flow of service A enters catch block. I expect it to stay in try block only as I want to process further based on the data.
Any idea, how can I get around this thing? Or is this how it will behave even when I am using controller advice to manage exceptions? What should be the expected behavior in this case?
Please advice.
By default Feign throws FeignException for any error situation.
Make use of fallback mechanism to handle failures.
#FeignClient(name = "FeignClient", url = "http://localhost:8081/ServiceB/hello", fallback= FeignApiFallback.class)
public interface FeignApi {
#RequestMapping(method = RequestMethod.GET)
ResponseEntity<?> hello();
}
#Component
class FeignApiFallback implements FeignApi {
#Override
public ResponseEntity<?> hello() {
//do more logic here
return ResponseEntity.ok().build();
}
}
make sure you add below property to wrap methods in hystrix commands in recent releases
feign.hystrix.enabled=true
Any status other than 200, feign client will consider it as an exception and you are setting HttpStatus.INTERNAL_SERVER_ERROR in your controller advice.
You can use custom ErrorDecoder
refer https://github.com/OpenFeign/feign/wiki/Custom-error-handling
I am using Spring Boot 1.5, and I have a controller that executes asynchronously, returning a CompletableFuture<User>.
#RestController
#RequestMapping("/users")
public class UserController {
#Autowired
private final UserService service;
#GetMapping("/{id}/address")
public CompletableFuture<Address> getAddress(#PathVariable String id) {
return service.findById(id).thenApply(User::getAddress);
}
}
The method UserService.findById can throw a UserNotFoundException. So, I develop dedicated controller advice.
#ControllerAdvice(assignableTypes = UserController .class)
public class UserExceptionAdvice {
#ExceptionHandler(UserNotFoundException.class)
#ResponseStatus(HttpStatus.NOT_FOUND)
#ResponseBody
public String handleUserNotFoundException(UserNotFoundException ex) {
return ex.getMessage();
}
}
The problem is that tests are not passing returning an HTTP 500 status and not a 404 status in case of an unknown user request to the controller.
What's going on?
The problem is due to how a completed exceptionally CompletableFuture handles the exception in subsequent stages.
As stated in the CompletableFuture javadoc
[..] if a stage's computation terminates abruptly with an (unchecked) exception or error, then all dependent stages requiring its completion complete exceptionally as well, with a CompletionException holding the exception as its cause. [..]
In my case, the thenApply method creates a new instance of CompletionStage that wraps with a CompletionException the original UserNotFoundException :(
Sadly, the controller advice does not perform any unwrapping operation. Zalando developers also found this problem: Async CompletableFuture append errors
So, it seems to be not a good idea to use CompletableFuture and controller advice to implement asynchronous controllers in Spring.
A partial solution is to remap a CompletableFuture<T> to a DeferredResult<T>. In this blog, an implementation of a possible Adapter was given.
public class DeferredResults {
private DeferredResults() {}
public static <T> DeferredResult<T> from(final CompletableFuture<T> future) {
final DeferredResult<T> deferred = new DeferredResult<>();
future.thenAccept(deferred::setResult);
future.exceptionally(ex -> {
if (ex instanceof CompletionException) {
deferred.setErrorResult(ex.getCause());
} else {
deferred.setErrorResult(ex);
}
return null;
});
return deferred;
}
}
So, my original controller would change to the following.
#GetMapping("/{id}/address")
public DeferredResult<Address> getAddress(#PathVariable String id) {
return DeferredResults.from(service.findById(id).thenApply(User::getAddress));
}
I cannot understand why Spring natively supports CompletableFuture as return values of a controller, but it does not handle correctly in controller advice classes.
Hope it helps.
For those of you who still run into trouble with this : even though Spring correctly unwraps the ExecutionException, it doesn't work if you have a handler for the type "Exception", which gets chosen to handle ExecutionException, and not the handler for the underlying cause.
The solution : create a second ControllerAdvice with the "Exception" handler, and put #Order(Ordered.HIGHEST_PRECEDENCE) on your regular handler. That way, your regular handler will go first, and your second ControllerAdvice will act as a catch all.
I'm facing an issue with Spring (and kotlin?), where my global error handlers do not catch any exceptions thrown within a custom converter.
I know spring supports string->UUID mapping by default, but I wanted to explicitly check if an exception is actually thrown. Which it is the following converter. The behaviour is the same with and without my own implementation of the converter.
My WebMvcConfuguration looks as follows:
#Configuration
class WebMvcConfiguration : WebMvcConfigurerAdapter() {
override fun addFormatters(registry: FormatterRegistry) {
super.addFormatters(registry)
registry.addConverter(Converter<String, UUID> { str ->
try {
UUID.fromString(str)
} catch(e: IllegalArgumentException){
throw RuntimeException(e)
}
})
}
And this is my GlobalExceptionHandler:
(it also contains other handlers, which I ommitted for brevity)
#ControllerAdvice
class GlobalExceptionHandler : ResponseEntityExceptionHandler() {
#ExceptionHandler(Exception::class)
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ResponseBody
fun handleException(ex: Exception): ApiError {
logger.info(ex.message, ex)
return ApiError(ex.message)
}
}
And finally, the controller:
#Controller
class MyController : ApiBaseController() {
#GetMapping("/something/{id}")
fun getSomething(#PathVariable("id") id: UUID) {
throw NotImplementedError()
}
}
Exceptions inside controller (for example the NotImplementedError) methods are caught just fine. But the IllegalArgumentException thrown within the converter when invalid UUIDs are passed is swallowed, and spring returns an empty 400 response.
My question now is: How do I catch these errors and respond with a custom error message?
Thanks in advance!
I had the same problem. Spring swallowed any IllegalArgumentException (ConversionFailedException in my case).
To get the behavior i was looking for; i.e. only handling the listed exceptions and using default behavior for the other ones, you must not extend the ResponseEntityExceptionHandler.
Example:
#ControllerAdvice
public class RestResponseEntityExceptionHandler{
#ExceptionHandler(value = {NotFoundException.class})
public ResponseEntity<Object> handleNotFound(NotFoundException e, WebRequest request){
return new ResponseEntity<>(e.getMessage(), new HttpHeaders(), HttpStatus.NOT_FOUND);
}
}
I checked the solution from #georg-moser. At first, it looks good, but it looks it contains another issue. It translates all exceptions to the HTTP code of 500, which is something one not always wants.
Instead, I decided to overwrite the handleExceptionInternal method from the ResponseEntityExceptionHandler.
In my case logging the error was enough, so I ended up with the following:
#Override
#NonNull
protected ResponseEntity<Object> handleExceptionInternal(#Nonnull final Exception e,
final Object body,
final HttpHeaders headers,
final HttpStatus status,
#Nonnull final WebRequest request) {
final ResponseEntity<Object> responseEntity = super.handleExceptionInternal(e, body, headers, status, request);
logGenericException(e);
return responseEntity;
}
I hope it helps!
After some more trial and error, I have found a solution:
Instead of using #ControllerAdvice, implementing a BaseController that others inherit from and adding the exception handlers there works.
So my Base controller looks like this:
abstract class ApiBaseController{
#ExceptionHandler(Exception::class)
#ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR)
#ResponseBody
fun handleException(ex: Exception): ApiError {
return ApiError(ex.message)
}
}
If anyone can elaborate on why it works like this and not the other way, please do so and I will mark your answer as accepted.
I am not able to override default spring boot error response in REST api. I have following code
#ControllerAdvice
#Controller
class ExceptionHandlerCtrl {
#ResponseStatus(value=HttpStatus.UNPROCESSABLE_ENTITY, reason="Invalid data")
#ExceptionHandler(BusinessValidationException.class)
#ResponseBody
public ResponseEntity<BusinessValidationErrorVO> handleBusinessValidationException(BusinessValidationException exception){
BusinessValidationErrorVO vo = new BusinessValidationErrorVO()
vo.errors = exception.validationException
vo.msg = exception.message
def result = new ResponseEntity<>(vo, HttpStatus.UNPROCESSABLE_ENTITY);
result
}
Then in my REST api I am throwing this BusinessValidationException. This handler is called (I can see it in debugger) however I still got default spring boot REST error message. Is there a way to override and use default only as fallback? Spring Boot version 1.3.2 with groovy. Best Regards
Remove #ResponseStatus from your method. It creates an undesirable side effect and you don't need it, since you are setting HttpStatus.UNPROCESSABLE_ENTITY in your ResponseEntity.
From the JavaDoc on ResponseStatus:
Warning: when using this annotation on an exception class, or when setting the reason attribute of this annotation, the HttpServletResponse.sendError method will be used.
With HttpServletResponse.sendError, the response is considered complete and should not be written to any further. Furthermore, the Servlet container will typically write an HTML error page therefore making the use of a reason unsuitable for REST APIs. For such cases it is preferable to use a ResponseEntity as a return type and avoid the use of #ResponseStatus altogether.
I suggest you to read this question: Spring Boot REST service exception handling
There you can find some examples that explain how to combine ErrorController/ ControllerAdvice in order to catch any exception.
In particular check this answer:
https://stackoverflow.com/a/28903217/379906
You should probably remove the annotation #ResponseStatus from the method handleBusinessValidationException.
Another way that you have to rewrite the default error message is using a controller with the annotation #RequestMapping("/error"). The controller must implement the ErrorController interface.
This is the error controller that I use in my app.
#RestController
#RequestMapping("/error")
public class RestErrorController implements ErrorController
{
private final ErrorAttributes errorAttributes;
#Autowired
public MatemoErrorController(ErrorAttributes errorAttributes) {
Assert.notNull(errorAttributes, "ErrorAttributes must not be null");
this.errorAttributes = errorAttributes;
}
#Override
public String getErrorPath() {
return "/error";
}
#RequestMapping
public Map<String, Object> error(HttpServletRequest aRequest) {
return getErrorAttributes(aRequest, getTraceParameter(aRequest));
}
private boolean getTraceParameter(HttpServletRequest request) {
String parameter = request.getParameter("trace");
if (parameter == null) {
return false;
}
return !"false".equals(parameter.toLowerCase());
}
private Map<String, Object> getErrorAttributes(HttpServletRequest aRequest, boolean includeStackTrace)
{
RequestAttributes requestAttributes = new ServletRequestAttributes(aRequest);
return errorAttributes.getErrorAttributes(requestAttributes, includeStackTrace);
} }