what is the right way to handle errors in spring-webflux

Question

I\'ve been doing some research using spring-webflux and I like to understand what should be the right way to handle errors using Router Functions.

I\'ve created an s

Answer 1

A quick way to map your exceptions to http response status is to throw org.springframework.web.server.ResponseStatusException / or create your own subclasses...

Full control over http response status + spring will add a response body with the option to add a reason.

In Kotlin it could look as simple as

@Component
class MyHandler(private val myRepository: MyRepository) {

    fun getById(req: ServerRequest) = req.pathVariable("id").toMono()
            .map { id -> uuidFromString(id) }  // throws ResponseStatusException
            .flatMap { id -> noteRepository.findById(id) }
            .flatMap { entity -> ok().json().body(entity.toMono()) }
            .switchIfEmpty(notFound().build())  // produces 404 if not found

}

fun uuidFromString(id: String?) = try { UUID.fromString(id) } catch (e: Throwable) { throw BadRequestStatusException(e.localizedMessage) }

class BadRequestStatusException(reason: String) : ResponseStatusException(HttpStatus.BAD_REQUEST, reason)

Response Body:

{
    "timestamp": 1529138182607,
    "path": "/api/notes/f7b.491bc-5c86-4fe6-9ad7-111",
    "status": 400,
    "error": "Bad Request",
    "message": "For input string: \"f7b.491bc\""
}