Common sign-in with kDrive and kSync

[phhusson]

Is your feature request related to a problem? Please describe.
When setting-up an infomanak account, the user needs to login three times, one in ikmail, one in kdrive, one in ksync, that's rather annoying.

Describe the solution you'd like
I would like that setting-up the account in ikmail, will share the credentials with kdrive and ksync. Ideally the sign-in activity would allow a flag to close the app at the end of the sign-in, cf additional context

Additional context
End-goal: I want to make an Android custom ROM where instead of signing into a Google account, the user logs into an Infomaniak account, and they get their mails/contacts/agenda/drive

[JorisBodin]

We've been thinking about it for nearly 4 years

But the oauth standard doesn't allow it. Because when you log on to kDrive, you only get the authorizations specific to kDrive.
So you'd have to cheat to get there.

If you have any ideas, we're open.

We're a long way from offering an infomaniak custom rom. Even if the idea is sexy.

[phhusson]

Thanks for your answer.

Sorry I'm a noob in OAuth, so if you don't mind I'd like to pick your brain, with a couple of questions:

• I can request an OAuth token with full mail + drive + sync access, right? So I could make my own app making a "global" token, and then share it?
• Can OAuth create derivative tokens with lesser privileges? Assuming I created a token with mail + drive + sync, can I generate a token that only allows mail? Or maybe that will require a token with full privilege (that would be okay I think)

Assuming it's possible to make derivative tokens, assuming I make a dedicated app for "admin" login that exposes derivative tokens through Android's standard "Account" API, assuming I write the code for integration in ikmail/kdrive/ksync, would you be open to merging it?

(I'm definitely not saying I'm going to do it, but I'd like to know before trying to do it)