Creating a REST connection fails and shows error "HTTP protocol error 417 (Expectation Failed)".
This happens to POST request only when the connector contains a request body. When request body is empty, then the connection can be created (but no data is returned as this is an invalid request).
Root cause of the issue is that when a POST call contains a Request body, then Qlik REST connector automatically add "Expect: 100-continue"
to the request headers. This header is a common way to indicates that everything so far is OK and that the client should continue with the request, or ignore it if it is already finished.
Most API sources accept this header as it is a common one. However, some API sources do not, and returns HTTP protocol error 417.
For more information about this header, please refer to:
The issue is under investigation in bug QVXREST-629
While waiting for R&D feedback on the bug, a possible work-around would be to work with the API source owner to see if they can configure the system to accept this header in POST requests.Environment:
As of the latest version (Qlik Sense February 2018 - REST Connector 1.3), the bug is still under investigation.