My app needs continuous/background access to file data (docs and spreadsheets) that the user selects through the Google Picker API. Meaning, I need to access the file e.g. days after it was first selected/picked by the user.
I can get temporary access to the file using the OAuth token created by the picker (and access the file via the docs/spreadsheets API), but this token expires and cannot be refreshed (AFAICT).
My app can generate auth tokens for a user in the background. But, when I try to use an auth token generated for the same user, on the same App/Client ID, with the same scopes I get a 403 forbidden error.
Is there a way to get long-lasting access to files via the Google Picker API without the user re-authenticating the file before each access?
I can expand my scopes on the backend (I'm using drive.file currently), but I want to avoid using restricted scopes (like drive.readonly).