Either MissingServletRequestPartException and MissingServletRequestParameterException should throw a Bad Request error code

[xtremebiker]

Overview of the issue

The generated ExceptionTranslator catches the MethodArgumentNotValidException and the CustomParameterizedException, but MissingServletRequestPartException and MissingServletRequestParameterException should as well be caught and treated to return bad request codes.

Reproduce the error

Created a new REST endpoint to display entity field suggestions with this signature:

@GetMapping("/installations/suggestions")
@Timed
public Set<String> getSuggestions(
@RequestParam(required = false, defaultValue = "") String pattern,
            @RequestParam String field);

Then created a new integration test that should return 400 since the required field parameter is missing:

@Test
@Transactional
public void suggestionsRequiredType() throws Exception {
    // Get the installation
    restInstallationMockMvc.perform(get("/api/installations/suggestions?pattern=cio", installation.getId()))
            .andExpect(status().isBadRequest());
}

But the test fails as the endpoint returns a 500 response instead of 400. That's because the exception is caught by the standard processor:

@ExceptionHandler(Exception.class)
public ResponseEntity<ErrorVM> processException(Exception ex) {
    log.error(ex.getMessage(), ex);
    BodyBuilder builder;
    ErrorVM errorVM;
    ResponseStatus responseStatus = AnnotationUtils.findAnnotation(ex.getClass(), ResponseStatus.class);
    if (responseStatus != null) {
        builder = ResponseEntity.status(responseStatus.value());
        errorVM = new ErrorVM("error." + responseStatus.value().value(), responseStatus.reason());
    } else {
        builder = ResponseEntity.status(HttpStatus.INTERNAL_SERVER_ERROR);
        errorVM = new ErrorVM(ErrorConstants.ERR_INTERNAL_SERVER_ERROR, "Internal server error");
    }
    return builder.body(errorVM);
}

Suggest a Fix

Adding this in the ExceptionTranslator solved it:

@ExceptionHandler(MissingServletRequestParameterException.class)
@ResponseBody
@ResponseStatus(HttpStatus.BAD_REQUEST)
public ErrorVM processMissingServletRequestParameterException(MissingServletRequestParameterException exception) {
    return new ErrorVM(ErrorConstants.ERR_BAD_REQUEST, exception.getMessage());
}

JHipster Version(s)

4.4.1

[jdubois]

Understood -> this part of JHipster isn't very clear, let me "handle" this :-)

[jdubois]

OK so this part of JHipster is much worse than I thought!!

• The back-end code isn't as good as it should be, which is what you point to
• It also sends error messages that should be taken into account by the front-end, using our i18n error codes, but none of them are present. Even worse, there's a "error.accessDenied" and "error.403" that do the same thing but don't work together...

Anyway: that's bad, it takes some time to fix (as i18n is huge now), and I know what to do -> I should have some time this week (I have a 7 hour flight on Thursday), so I'm assigning this to myself.

[cbornet]

There are other standard Spring exceptions that we override : https://github.com/spring-projects/spring-framework/blob/a0bce618c2f51d8af1fc00ee2c3868ba2c8e0045/spring-webmvc/src/main/java/org/springframework/web/servlet/mvc/method/annotation/ResponseEntityExceptionHandler.java#L106 We should probably do something for them also. Also, I propose to use rfc7807 application/problem+json errors. I believe they should work well with our front-end.

[cbornet]

After some digging, I think we should remove our ExceptionHandler beans and use a global ErrorAttributes instead. I'll try something asap.