app slow to show configured servers on start-up

It takes around ~2 seconds before the server is shown, until that time this is what is shown:

Is there network activity at this stage? What is fetched? Why is it so slow? Why does it not happen in the background?

[dzolnai]

The server_list, and organization_list JSONs and their signatures are fetched, then verified against each other.
After that the JSON needs to be parsed, and the view should be updated. This should all happen under 1 sec in optimal circumstances, but on a slower connection or device it might take a bit longer.

organization_list.json should NEVER be fetched on (subsequent) start-up, only when choosing an organization, which typically only happens once... As for server_list.json that could easily be a background thread that doesn't impact the loading of the UI.

See also https://github.com/eduvpn/documentation/blob/v2/SERVER_DISCOVERY.md

[dzolnai]

Oh sorry, I thought this was the search screen, my mistake.
There the app waits for the server_list, but I have applied a fix to not wait if the user does not have an organization added.
Otherwise it will wait 3 seconds, because we have some retry-after-failure which checks again after 3 seconds.
This is required because sometimes it wants to refresh this list when coming back from a disconnect, and it needs some time to get a working connection again.

[dzolnai]

Should be better now.

It is not. Just showing a banner that it is refreshing the list is not okay. There should be no banner and no delay. There is no need for network activity at all! At least not on the main thread. If it can update in the background, fine.

[dzolnai]

Server list is cached now for one hour.

Actually you are not allowed to do that. The web server indicates information about caching!

Cache-Control: no-cache

See also: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control