Node SDK: JSON error on empty response

[haggholm]

When querying Looker using the Node SDK, we occasionally see an Error: Unexpected end of JSON input. This is coming from the parseResponse() function in nodeTransport.js:

            if (!(result instanceof Object)) {
              result = JSON.parse(result.toString());
            }

In this instance, the response is actually empty, and JSON.parse("") throws an error.

1. The error is not particularly good or informative. In fact, I don't know whether the library should throw an error on an empty response or not, but a JSON parse error is definitely not what I'd expect.
2. Why is the API returning an empty response in the first place? The sample query where I was able to reproduce this does not actually run in the Looker SQL editor either, failing with ERROR: Operation not allowed on schema "pg_internal". Fair enough, that's probably an error on my part with the test data; but I would have expected some kind of informative error response rather than an empty string that then causes a parse error.
   • It is not entirely clear whether all instances of this error are related to models that fail when queried from the Looker web UI; if I can obtain more information on that, I will update this ticket.