See if login time can be reduced

[hgwood]

Login time can be quite long and this is especially annoying for this app because:

• time in the app is very short, so login time is significant
• most user will come no more than once a month which means most logins will be cold (no token renewal possible)

As far as I could see most of the time is waiting for the HTTP request to Auth0, so I'm not sure how we can improve, but I'd be happy for someone to have another look.

As an alternative, I guess we could take the optimistic UI approach and show the vote screen immediately after the user comes back from Auth0, not waiting for the HTTP response, and then only if login is rejected the app can show an alert and reload, or something like that.

[hgwood]

For the optimistic UI part, see #162.

Regarding the Auth0 call, currently the access token is opaque and there is no choice but to call Auth0 to validate it. However, we could change the authentication configuration to request an access token in the JWT format. That would allow exchangeToken to validate the token without calling Auth0.

[hgwood]

@jlandure Gave me another idea. The Auth0 domain is hosted in Europe, while the Cloud function is hosted in the US. By co-locating the two we should have less latency.

[jlandure]

Hey @hgwood 👋

Indeed, the latency between Europe/America still remains around ~150ms. ⚡️
I think there is nothing to change the default zone/region. You have to recreate the function. 😊

[hgwood]

Closed by mistake.