How to verify the Token generated by the NextCloud OAuth Provider?


we want to create an Angular Application which talks to NextCloud thru a Middleware we create in ASP.NET Core.

We would like to use the OAuth Provider integrated in NextCloud so we don’t have the full credentials in the Middleware What could we do to check if the Token the Angular App passes to our MIddleware is valid and was successfully issued by NextCloud?

The Flow we have in mind would be:

  • User starts the Angular App and gets redirected to the "NextCloud Grant Access OAuth Flow "
  • Angular receives the Bearer Toke from the …/Token Endpoint
  • Angular tries to load data from our ASP Middleware and pass the Auth Token in the header
  • ASP verfies (in a tbd. way) the Token is valid and either returns the requested Information when the Token was just issued by NextCloud or returns an error message.

We already tried to verify the the Token using but it seems like the Token returned from NextCloud isn’t a JWT Token.

Any Ideas how we could achive this?

Thanks in advance and kind regards