Allow manipulation of provider response

[jackHedaya]

Summary of proposed feature
I believe it would be useful for there to be a callback for right after the Provider API is hit.

Purpose of proposed feature
This is helpful because some OAuth Providers will send back tokens in different formats such as refresh_token instead of refreshToken.

Detail about proposed feature
There would be a res callback.

Potential problems
None that I could tell.

Describe any alternatives you've considered
N/A

Please indicate if you are willing and able to help implement the proposed feature.
Yes

[balazsorban44]

Hi there, do you have a special case where this has been a problem?

As far as I can tell, the OAuth spec says it has to be in the form at refresh_token, and as you see here:

next-auth/src/server/lib/oauth/client.js

Line 167 in fb8ec8a

const refreshToken = results.refresh_token

we do expect it to be refresh_token.

If there is an OAuth provider that for some reason returns a refreshToken, we could add an extra if statement for that particular provider, but to keep the user-facing API simple (#1022 ), I wish not to expose a new option if your case is an isolated one. You could rather add a new provider to the list of supported providers, and we can handle a special case internally, using the provider.id.

Adding

const refreshToken = results.refresh_token ?? results.refreshToken

is a no-brainer also.

[jackHedaya]

That's my bad then, I'm not sure why my custom provider isn't working. I opened a discussion issue and I'll give that a try. Thank you!