FCL: Check if user's wallet connection is still valid when creating an authorization request

Problem

Currently, FCL remembers when a user logs into a wallet and persists the connection when user comes back to the dApp page. This is great for UX.

When dApp calls the signing function from fcl.currentUser().authorization, FCL creates a POST request to initiate the authorization process. However, the wallet connection might not be valid anymore at this time, if user comes back to the dApp long after they first logged in. Currently there is no way for the wallet service to tell FCL that the connection is not valid anymore.

Expected

There may be multiple ways to improve the process.

1. In the signature authorization request, define a response for the wallet service to tell FCL that the connection has already expired.
2. Before creating the authorization request, define an API to check if the wallet connection is still valid (maybe from some information that /hook API provided).
3. In /hook API, the wallet provider tells FCL how long the connection will be valid for.

I’d prefer 2 or 3. They will also work for other future requests to the wallet service other than the signature request.

[orodio]

@boczeratul I like the idea of doing it silently, treating it as if we know roughly who they are, but not how to do things on their behalf.

@boczeratul what do you think about this:

• Treat Authn expiry as fcl.unauthenticate()
• Treat Authz expiry as fcl.unauthenticate() right before a point that requires an authentication?

[orodio]

@boczeratul I believe we are correctly respecting the expire value you are sending us, which I think solves this issue. Going to close this, if you find any issues with it let us know and I can re-open.