SpringBoot/Kotlin: Multipart MaxUploadSizeExceededException handler does not fire - spring

Question

Please excuse any horrible mistakes, I literally picked up Kotlin fully and some Spring about a week ago, due to a project requirement. I am trying to create a simple RESTful API with an endpoint that can accept a file via Multipart. Later on, there will be a few pages outside the API that will display HTML, I am using Koreander for that. From what I can see, and based on Java tutorials, exception handling should work like this.
For the API, my defined exception handler for MaxUploadSizeExceededException, however, does not fire at all. My application.kt:
#SpringBootApplication
#EnableConfigurationProperties(StorageProperties::class)
class JaApplication {
#Bean fun koreanderViewResolver(): ViewResolver = KoreanderViewResolver()
}
fun main(args: Array<String>) {
runApplication<JaApplication>(*args)
}
My controller:
#RestController
#RequestMapping("/api")
#EnableAutoConfiguration
class APIController {
#PostMapping(
value = "/convert",
produces = arrayOf(MediaType.APPLICATION_JSON_VALUE)
)
fun convert(#RequestParam("file") multipartFile: MultipartFile): Result {
return Result(status = 0, message = "You have uploaded: ${multipartFile.getOriginalFilename()}.")
}
}
#ControllerAdvice
class ExceptionHandlers {
#ExceptionHandler(MultipartException::class)
fun handleException(e: MultipartException): String = Result(status = 1, message = "File is too large.")
}
}
When I am attempting to post a large file via curl, I get a JSON reply:
curl -F 'file=#path-to-large-file' http://localhost:8080/api/convert
{"timestamp":"2018-11-27T15:47:31.907+0000","status":500,"error":"Internal Serve
r Error","message":"Maximum upload size exceeded; nested exception is java.lang.
IllegalStateException: org.apache.tomcat.util.http.fileupload.FileUploadBase$Siz
eLimitExceededException: the request was rejected because its size (4294967496)
exceeds the configured maximum (529530880)","path":"/api/convert"}
Is it possible that Tomcat does not pass this exception to Spring? If yes, how may I go about catching this? It also works if I can set the size to unlimited and check for file size at upload time, though I would need to do that before the server starts receiving the file, and I assume by the time I get to the /api/convert endpoint, it is too late.
Thanks for any help.

Answer 1

Found the issue. I'm posting it for anyone else who might have the same issue in the future.
#ControllerAdvice
class ExceptionHandlers():ResponseEntityExceptionHandler() {
#ExceptionHandler(MaxUploadSizeExceededException::class)
fun handleException(e: MultipartException, request:WebRequest): ResponseEntity<Any> {
return handleExceptionInternal(e, Result(message = "File is too large."), HttpHeaders(), HttpStatus.PAYLOAD_TOO_LARGE, request)
}
}