How to throw errors from REST API calls (CAP CDS and Fiori app)

[Harshi]

I have a CAP and Fiori app. For a particular value help field, I call a REST API inside the handler on READ event of the field. In case the API responds in errors, I can see those errors only in the network tab. The ODATA API call still shows 200. How to propagate the exception to UI?

[T1mey]

Have you tried

req.error(40x, "error msg");

https://cap.cloud.sap/docs/node.js/events#req-error

[Harshi]

Hi T1mey,
Thank you for your reply. I use Kotlin for Handlers and I use the req.err equivalent which is ServiceException. I use it as below

catch (e: RestClientResponseException) {
            log.error { "Failed. Response: ${e.statusCode} ${e.responseBodyAsString}" }
            if (e.statusCode == NOT_FOUND) {
                messages.errorCode("notFound")
            }
            messages.errorCode("error", e.responseBodyAsString)
            messages.throwIfError()
        }

[T1mey]

and

https://cap.cloud.sap/docs/java/event-handlers/indicating-errors#exceptions

[Harshi]

Hi T1mey, This does not help either