409 Error: The requested resource is not concurrent

[Andrew_Mai]

In my SAP/CAP, sometime, the request will return a error like this:

Not sure what will cause this error? And how to prevent it. Since it happen very randomly, I have no clue what can cause this issues.

[gregorw]

Does it happen with PUT requests as in the description of 409 - Conflict?

[Andrew_Mai]

No. This API is an function endpoint, which will trigger to export an excel file. So it should be GET method, not PUT.

[gregorw]

Maybe you can share a sample project on a public Git repository.

[Andrew_Mai]

I was able to resolve this issues by add a random parameter after the function, so it not happen any more. But still, the issues is coming from the If-Match headers if I'm not wrong. Will try to take another look at this issues.

[david_kunz2 · Accepted solution]

Hi andrew.mai ,

Yes, this happens if you're sending `if-match` or `if-none-match` headers and the respective entity has no etag configured. In future versions of @sap/cds (Node.js) we will ignore those headers. Currently, the error 'The requested resource is not concurrent' is thrown.

Best regards,
David