Handling authority server errors with custom login screen.

[emrsn-SebastianVancea]

I am trying to handle 400 (invalid_grant, i.e. we deleted the refresh_token to force a logout for some users) and 500 errors from our custom authority server.

However, as it is right now in OAuth2.swift:196, doRefreshToken returns with callback(nil) in these cases and so it will always try show the Login screen (registerClientIfNeeded) instead of allowing me to just show a 'Try later' error.

Another side of this is in OAuth2.swift:358 it will throw an error if there is an invalid_grant, but it will set the refreshToken to nil if there was a 500.

Am I missing something and I should just write my own OAuth2 subclass? In this case I would probably need to override the OAuth2DataLoader as well since right now OAuth2.authorize is final

[p2]

There have recently been some changes there, have you seen them? In tryToObtainAccessTokenIfNeeded it will now return the error in the callback (except if it's a 401). This should result in didFail being called in your case, is this not the case?

You're right about the 500 issue in doRefreshToken; happy to review a PR that doesn't delete the token on 500s! :)

[KimKellerRasmussen]

When will this be implemented ?

Refresh token should not be cleared if connection is missing or is lost; unavailable, timeout, ... etc.