Update parameters or other Request from M Code

[briceem]

Hi,

I would like to use an API which has a particular authentication flow, I quote: 

Use the API Client ID and TGT generated in user interface (web app) to authenticate.
The call returns a TGT and a token. The TGT is valid for 180 days, the token is cycled with every call.
Every API call returns a fresh token in its response metadata, for use in the subsequent call.
The TGT is used whenever authentication is required.

So in order to use it in PowerBI (I would also need data service ), I would like to:

1) fill the initial TGT in an dedicated request (or parameters or other thing ??)

2) use this TGT to make a POST to the token endpoint

3) from the response:

a) retrieve the TGT and update the dedicated request (or parameters or other thing ??) from step 1, so it will be up-to-date for next refresh

b) retrieve the token and use it for subsequent request.

I have no issue to do every step except the 3)a ?

I tried to use parameters, but didn't figure out how to update it ?

I tried to use dedicated requests but failed to update it.

I even think about azure keyvault, but unfortunately I noticed PUT method is not available in Power Query M 😓

Thanks in advance