Change authentication to apples new SRP6a

[PflaeginGmbh]

Hello there,
as mentioned here, the authentication has changed. This was solved in the origin repository pyicloud.
These fixes solve the authentication problem and are a slightly modified version of the mentioned solution.

[PflaeginGmbh]

This works for me very well, so i hope that we can finish this task as soon as possible.

[Eugene-Polonsky]

I'm getting ('Invalid authentication token.', ICloudPyAPIResponseException('Missing apple_id field')) when trying this.

[PflaeginGmbh]

Okay, in the pycloud thread here users experience this your issue too.

First of all, 2FA has to be enabled. In addition here is maybe a workaround for enabled 2FA with this error.

[Eugene-Polonsky]

Tried all that, still same error. It looks like the code is trying to retrieve a session token, but is providing a null dsWebAuthToken. Hence the error.

[Eugene-Polonsky]

This seems to be because session_data does not contain session_token or trust_token. Instead, it contains 'scnt' and 'client_id' and that's it.

[Eugene-Polonsky]

In the original fastlane solution, they reference X-Apple-HC / Challenge headers. I am not seeing that in this solution. Could that be related?

[Eugene-Polonsky]

Ok figured it out. Have to use actual password, not app-specific password. Works now.

[drallgood]

Can this be merged so the downstream iCloud-docker is fixed too?

[mandarons]

It looks like Apple hasn't completely moved to this authentication method yet (e.g. working fine for me without these changes). Is there any way to detect if SRP6a is required for a given apple account? If not, we can have this as a second method if the default (legacy?) authentication fails.