Rest API Oauth2 as a data source

[MSchultz93]

I'm relatively new to Power BI. I have a question regarding the best practice of the OAuth2 flow using a Rest API. I want to do the following,

1. Automatically update the refresh token and access token

2. Use the access token to paginate data from the rest API.

I have written the following function that retrieves a new refresh token and access token in the advanced editor. However, I need to manually put the refresh token into the function. Can someone give me advice on how I should set it up?

() =>
let
grant_type = grant_type,
refresh_token="1111122222333333",
client_id = client_id,
client_secret = client_secret,
requestBody = "grant_type=" & grant_type & "&refresh_token=" & refresh_token & "&client_id=" & client_id & "&client_secret=" & client_secret,
options = [ Headers = [ #"Content-Type" = "application/x-www-form-urlencoded" ],
Content = Text.ToBinary(requestBody) ],
response = Web.Contents("https://auth.happyapi123.com/oauth/token", options),
json = Json.Document(response)
in
json

Here is the code that I have written, note I've hidden private information. grant_type, client_id and client_secret are parameters

I am not sure how to proceed, or if I should tackle it in a different way

[amitchandak]

@MSchultz93 , refer if this can help

Rest source - Token based
https://www.advaiya.com/generate-dynamic-token-and-get-data-from-custom-api-in-power-bi/

[MSchultz93]

Hi, thank you for the reply!

I actually built my code from that link, however, on that website an access token is queried from a static URL with a username and password. The function never needs to change. My logic is more complicated. 

I have a query that is using a refresh token to obtain an access token and a refresh token. The new refresh token must be used the next time I generate an access token. Therefore the query that creates the access token must use the last created refresh token and therefore the query is not static like the one in the link.

Do you have any advice on that? If you need any clarification let me know