⚡️ decrease time-to-interactive

[jsulpis]

Related to #41

I made quite a few changes, I hope it is not too much for one PR. But the logging time (at least perceived) is much shorter.

Here is what I did:

• remove the call to the auth0 API authenticationClient.getProfile() in the exchangeToken function, which was not necessary since all we got from it was the user email, which we already have from the auth0 authentication. The call to this function was one of the longest so I think we can save several seconds on the production app just by removing it.
• change the order of some operations: use optimistic UI to display the main content right after the auth0 authentication, and display the rest after the Firebase authentication. Also fetch the list of agencies at the very end since it is in the second page so we don't need it straight away.
• display a little loader during the Firebase authentication when the main content is already there, to let the user know that there is still something happening in the background so they are not frustrated if an error message shows up (like campaign closed)

[hgwood]

Wow! Sounds awesome. I'll try to review and test it this week.

[EmrysMyrddin]

LGTM

[EmrysMyrddin]

For accessibility, can we use something else than a h2 to display information that is not really a title ?

[jsulpis]

I put a div instead

[hgwood]

I'm getting an error when running the app locally, I'm investigating.

[hgwood]

I'm afraid removing the call to Auth0 is not that easy. Your proposal is not secured. Anyone can call exchangeToken with any values for userId, userEmail, accessToken and get authenticated to Firebase. In the master version, the value for accessToken is validated against Auth0, which ensures that the token is legitimate and that the user really did authenticate to Auth0. This is why Auth0 is called, not just to get the email address. 🙂

[jsulpis]

I'm afraid removing the call to Auth0 is not that easy. Your proposal is not secured. Anyone can call exchangeToken with any values for userId, userEmail, accessToken and get authenticated to Firebase. In the master version, the value for accessToken is validated against Auth0, which ensures that the token is legitimate and that the user really did authenticate to Auth0. This is why Auth0 is called, not just to get the email address. 🙂

Indeed I forgot it was in an API function and thus not redundant with the authentication. I dropped the commit.

Hopefully with the optimistic UI it should still feel faster, but the total logging time will remain roughly the same (very long). So I am not sure if this PR can still close the associated issue ? It strange that some API calls take much more time on the production app than locally, but I won't be able to further analyse this issue.

[hgwood]

I'll come back to this PR next week :)

[hgwood]

I might have solution for the Auth0 call, see #41 (comment), but let's keep that for another PR.

[hgwood]

Finally got around to test this. It works nicely, thank you. I think it can be improved further. In the current form, the Stats button in the navbar is unresponsive while authenticating to Firebase. I don't think this has to happen. I'm gonna to test a few adjustment to see what I can do.

[hgwood]

OK, found something that works a bit better IMO, since it's now possible to navigate to the stats page immediately.