Getting access_token when using on-premise data gateway in the custom connector

[Shidin]

How can we pass the current logged in power apps user's access_token to a custom connector?
Custom connector connects to internally hosted APIs via the data gateway.

Context:
Client has a canvas app which does CRUD operations with an external system, facilitated by usage of a custom connector and APIs.

All the APIs are internal (not exposed via the internet). So the custom connector connects via on-prem data gateway.

The limitation of enabling that check-box is that we seem to be limited in our Authentication types to the below 3 options.

The APIs we are consuming are role-based. So they need to know + validate who the calling user is (via the JWT access_token). That's the use case.

Trying to see if any of the following scenarios work:

1. Get the user's access_token from the Power App and then pass it to the API as a HTTP header.
   (Might be able to pull it off using a Power Automate flow)
2. If #1 is not possible, then make the APIs public and with OAuth 2.0 auth, which will solve the problem. But if the APIs are made public, we need to go through security reviews and pen tests, which I am trying to avoid.

Thanks in advance!

[Dinesh]

I am not sure about getting the user's token from canvas app. But you can try to simulate the steps of Oauth flow using HTTP connector without creating custom connector.

1. Generate an access token depending on the API setup with HTTP call

2. Using the new token in the header for the actual API calls

[JonPowerApps]

Did you ever resolve this? 

[Shidin]

No supported wat to do this, as confirmed by Microsoft product team.

We could manipulate the YAML to include OAuth while connecting to on-premise was offered as a workaround, but its an undocumented approach.