The KE REST API should allow reactive KBs to give error messages back to the caller.

[Sophietje]

In GitLab by @barry.nouwt.tno.nl on Oct 26, 2023, 11:17

For example, when a reactive service is implemented and incoming bindings are invalid (because a datetime is in the past, or because an device ID is not found) it would be good if this information flows back to the proactive side. The ExchangeInfo is a good mechanism for this, but currently there is no way for users of the KE REST API to return an error message that ends up in the Exchange Info.

The users of the KE Java API can already throw an Exception from the ReactHandler that ends up in the ExchangeInfo.

Improve the KE REST API with such a feature.

[bnouwt]

To deal with this issue, we can probably extend the POST /sc/handle REST operation to send an error message instead of a binding set. So, instead of:

{
  "handleRequestId": 0,
  "bindingSet": [
    {
      "additionalProp1": "string",
      "additionalProp2": "string",
      "additionalProp3": "string"
    }
  ]
}

we can send:

{
  "handleRequestId": 0,
  "errorMessage": "A problem occurred while handling the incoming knowledge. The incoming date should not be in the future."
}