SignalR Core - Error: Websocket closed with status code: 1006

Question

I use SignalR in an Angular app. When I destroy component in Angular I also want to stop connection to the hub. I use the command:

this.hubConnection.stop();

But I get an error in Chrome console: Websocket closed with status code: 1006

In Edge: ERROR Error: Uncaught (in promise): Error: Invocation canceled due to connection being closed. Error: Invocation canceled due to connection being closed.

It actually works and connection has been stopped, but I would like to know why I get the error.

This is how I start the hub:

this.hubConnection = new HubConnectionBuilder()
      .withUrl("/matchHub")
      .build();

    this.hubConnection.on("MatchUpdate", (match: Match) => {
      // some magic
    })

    this.hubConnection
      .start()
      .then(() => {
        this.hubConnection.invoke("SendUpdates");
      });

EDIT

I finally find the issue. Its caused by change streams from Mongo. If I remove the code from SendUpdates() method then OnDisconnected is triggered.

    public class MatchHub : Hub
    {
    private readonly IMatchManager matchManager;

    public MatchHub(IMatchManager matchManager)
    {
        this.matchManager = matchManager;
    }

    public async Task SendUpdates() {
        using (var changeStream = matchManager.GetChangeStream()) {
            while (changeStream.MoveNext()) {
                var changeStreamDocument = changeStream.Current.FullDocument;
                if (changeStreamDocument == null) {
                    changeStreamDocument = BsonSerializer.Deserialize<Match>(changeStream.Current.DocumentKey);
                }
                await Clients.Caller.SendAsync("MatchUpdate", changeStreamDocument);
            }
        }
    }

    public override async Task OnDisconnectedAsync(Exception exception)
    {
        await base.OnDisconnectedAsync(exception);
    }
}

Method GetChangeStream from the manager.

        ChangeStreamOptions options = new ChangeStreamOptions() { FullDocument = ChangeStreamFullDocumentOption.UpdateLookup };
        var watch =  mongoDb.Matches.Watch(options).ToEnumerable().GetEnumerator();
        return watch;

But I don't know how to fix it.

Answer 1

This can be for many reasons but i think it is most likely this one:

I think this is because of how the server is handling the connected / disconnected events. I can't say for sure but the connection closing needs to handled correctly on the server also with code. Try overriding the built in On Connected /Disconnected methods on the server and see. My assumption only is that you're closing it but the server isn't closing properly and therefore not relaying the proper closed response.

found as a comment at : getting the reason why websockets closed with close code 1006

Where you don't need to change the connection/disconection because evrything works fine. But as an answer this one is the most likely.