HttpStatusCodeException - remove HttpStatusCode from message details

[membersound]

In terms of DRY (don't repeat yourself), I often feel that Spring adding the StatusCode in front of a HttpStatusCodeException is somehow counter-intuitive. And especially is against DRY, because the statuscode is anyway offered as http status code in the response.

Thus, I want to suggest the following test should succeed:

@Test
public void test() {
   assertEquals("junit", new HttpStatusCodeException(HttpStatusCode.FORBIDDEN, "junit"); //fails, because message = "403 junit"
}

Because as of now, if the HttpStatusCodeException is thrown from a @RestController, Spring renders a message like:

{ 
 ...
 "message": "403 junit"
 ...
}

Source:
HttpStatusCodeException.class:

	private static String getMessage(HttpStatusCode statusCode, String statusText) {
		if (!StringUtils.hasLength(statusText) && statusCode instanceof HttpStatus status) {
			statusText = status.getReasonPhrase();
		}
		return statusCode.value() + " " + statusText; //suggestion: remove the statusCode prefix here
	}
``

[snicoll]

I am not sure what the argument for DRY is. This is an exception that carry a status code, of course its message should output the status code.

Thus, I want to suggest the following test should succeed:

Sorry, but I really see no reason that this should be. This completely ignores the first argument of the exception.

[membersound]

Okay, but which exception then has to be thrown in Spring that creates a certain http statuscode in the response, and only carries the custom message? Without prefixing the message?

[snicoll]

which exception then has to be thrown in Spring

I am not sure what you're asking. We surely don't provide every exceptions with every possible use cases you may fancy. If you want an exception to behave like that, create your own.

Without prefixing the message?

It isn't the message. it is the statusText (please review the Javadoc).

[membersound]

Excuse me - I just noticed I wrote HttpStatusCodeException, but I ment: HttpClientErrorException (in case that matters).

Well let's say I want to throw some exceptions based on conditions, inside a RestController. Isn't HttpClientErrorException the correct exception to use?

If so, I would want to simply show the message to the user without prefixing the status code before my custom message. And that's not possible!

@RestController
public class MyController {
   @GetMapping("/test")
   public void test() {
        throw new HttpClientErrorException(HttpStatusCode.TOO_MANY_REQUESTS, "custom message");
   }
}

Result:

{ 
    "message": "429 custom message"
}
- with statuscode=429 in the response itself

Well and this is exactly misleading, as only the custom message should be present in the response body, because the 429 is already included in the httpcode alongside with the response. And it comes from HttpStatusCodeException.getMessage() as this prefixes the "statusText" with the httpcode.

And I still think that exposing the http status code twice (1st as statuscode in the response, and 2nd inside the message body) contradicts any DRY principle.

[bclozel]

HttpClientErrorException is an exception thrown by HTTP clients. Please ask a question on StackOverflow.

[membersound]

Oh, I then probably should switch to ResponseStatusException.