RequireHealthOverlay: App (require connection) and TxForm & Signer (require sync)

[axelchalon]

Part of #159

[Tbaut]

It's working great, one "weird" thing is that when the node not only disconnects, but it is turned off (by me), Fether turns totally white:
If that can help, the console shows ws.js:102 WebSocket connection to 'ws://127.0.0.1:8546/' failed: Error in connection establishment: net::ERR_CONNECTION_REFUSED because I turned off the light node.

(filed in #218)

[amaury1093]

(didn't try yet, but)

Let's say for some reason the light client takes 5 minutes to sync. If we do target aunts and grandmas, they will click around. 1/ they will see wrong balance at some point (might not be a big deal) and 2/ they might send txs before the light client is sycned. 2 should definitely be disabled.

[amaury1093]

Linked to #228. When we are not sync, do we allow:

• users to see their list of accounts? Yes, this probably won't slow down LC sync too much.
• users to see their balances? No, as this slows down the LC sync. We can show a loading placeholder/the oldest value we got.
• users to send tx? No.

So we basically only allow users to see their accounts, when we're syncing. Imo we can keep the overlay in this case.

EDIT: Rethought about it: it's still doable without the overlay. We just need to define what we disable when we're not sync (send tx button, input forms?) cc @Tbaut

[Tbaut]

The problem is somewhat more complex than:

• we sync
• we are synced

for me it's more:

• we are synced
• we sync and are far from the top (eg client just started and it might take a couple sec/min)
• we sync but we're not far from the top at all (eg client was running low on peer, temporary bad internet connection..)

^ the 3rd case is where the overlay was particularly annoying.

users to see their balances? No, as this slows down the LC sync. We can show a loading placeholder/the oldest value we got.

Can we have some kind of cache/older state eventually?
+1 for "the oldest value we got".
For a better UX we could add a text like "Syncing, account information might be outdated" at the bottom or on a tooltip when hovering the red/orange button.

[Tbaut]

Nice! it even shows the past balance of ETH.
Can we also have the same behaviour for the tokens?

When I launch Fether, I see a blank window for ~10s before it shows the accounts etc.
Should we have an overlay there with a message saying that we're launching Fether :) ? More than a sec without message feels long, I originally thought Fether had crashed!

[axelchalon]

Just realized that the fields (user input) will be reset if the error shows up, not sure how annoying this is

Nice! it even shows the past balance of ETH.
Can we also have the same behaviour for the tokens?

Wasn't intentional and not sure how to reproduce this non-intentionality for tokens :P

When I launch Fether, I see a blank window for ~10s before it shows the accounts etc.
Should we have an overlay there with a message saying that we're launching Fether :) ? More than a sec without message feels long, I originally thought Fether had crashed!

Good catch, will fix now

[axelchalon]

ready for testing

This PR:

• If not connected to the node, show a full-screen overlay
• If just not synced, show a partial overlay on the TxForm/Signer screens

[Tbaut]

Working well :) I'll create a dedicated issue for the balance