Connection status Online when Websockets connection failing

文書化されている uBlock Origin のフィルターで WebSocket リクエストをブロックして React セットアップで問題を再現し、その後 DirectLine の connectionStatus$ と activity$ を併せて観察します。まず DirectLine のコンストラクターと connectionStatus$ のライフサイクルを追跡します。完了条件は、継続的に失敗する wss 接続が最終的に Online になるのではなく、ConnectionStatus.FailedToConnect を報告することです。

We are using this library in our React app and I encounter this weird behaviour.

The problem

When disabled Websockets connection in Chrome browser using these steps:

1. Open Chrome and install this extension
2. Restart Chrome
3. Go to the Extensions
4. Click uBlock Origin, the dashboard window or popup should be viewed
5. From the dashboard, click on Settings (cogs icon, see image above)
6. In the settings go to My filters tab
7. Add ||*^$websocket to 1st line of the filter editor and hit Apply changes

I can see that it successfully blocks the wss connections as I can see failed requests in my network tab. The problem is that the connection status will eventually set to ConnectionStatus.Online. I would expect that it will be ConnectionStatus.FailedToConnect as the Websockets request are failing. We need this so we can react with our UI to this scenario and also to log this to our internal logging systems. I cannot see how to do it without proper connection status information, though.

Our setup

In the React code we are just initializing my DirectLine instance in effect hook:

  useEffect(() => {
    if (directLineTokenData) {
      const body = {
        token: directLineTokenData.token || '',
        conversationId: conversationId || '',
        ...COMMON_BOT_PROPERTIES,
      };
      setDirectLine(new DirectLine(body));
    }
    // eslint-disable-next-line react-hooks/exhaustive-deps
  }, [directLineTokenData]);

and in another we subscribe to the activity$ and connectionStatus$ observables:

 useEffect(() => {
    // eslint-disable-next-line no-console
    console.log('Starting subscription to all activities');
    const subscribtion = directLine?.activity$.subscribe(activity =>
      // eslint-disable-next-line no-console
      console.log('Received activity:', activity),
    );
    // eslint-disable-next-line no-console
    const connectionStatusSubscription = directLine?.connectionStatus$.subscribe(
      status => {
        switch (status) {
          case ConnectionStatus.Uninitialized:
            // eslint-disable-next-line no-console
            console.log('STATUS: uninitialized');
            break;
          case ConnectionStatus.Connecting:
            // eslint-disable-next-line no-console
            console.log('STATUS: connecting...');
            break;
          case ConnectionStatus.Online:
            // eslint-disable-next-line no-console
            console.log('STATUS: online');
            break;
          case ConnectionStatus.ExpiredToken:
            // eslint-disable-next-line no-console
            console.log('STATUS: expired token');
            break;
          case ConnectionStatus.FailedToConnect:
            // eslint-disable-next-line no-console
            console.log('STATUS: failed to connect');
            break;
          case ConnectionStatus.Ended:
            // eslint-disable-next-line no-console
            console.log('STATUS: ended');
            break;
          default:
            // eslint-disable-next-line no-console
            console.log('STATUS: unknown status', status);
        }
      },
      error => {
        // eslint-disable-next-line no-console
        console.error('Error subscribing to connection status', error);
      },
    );
    return () => {
      console.log('Stopping subscription to all activities');

      subscribtion?.unsubscribe();
      connectionStatusSubscription?.unsubscribe();
    };
  }, [directLine]);

Observing the problem

Console logs from our React app:

From the logs we can see that there is eventually a ConnectionStatus.Online connection status change, even though failing Websockets requests. What's interesting that it sets connection status to ConnectionStatus.FailedToConnect one time (before it is set to ConnectionStatus.Online)

Any help is appreciated 🙏