renew token in signalR after expired token

Question

I create a realtime connection via SignalR From client(angular 9) and server(asp.net core 3.1) and Authorize hub by JWT Token such as below code :

 private createConnection() {
      this.hubConnection = new HubConnectionBuilder().withUrl(`${this.appConfig.hubEndpoint}/Hubs`,
        { accessTokenFactory: () => jwtToken })
        .withAutomaticReconnect()
        .build();
  }

  private startConnection(): void {
    this.hubConnection
      .start()
      .then(() => {
        this.connectionIsEstablished = true;
        this.connectionEstablished.emit(true);
      })
      .catch(err => {
        console.log('Error while establishing connection, retrying...');
      });
  }

this works fine until the token expired. According to my research, after receiving the new token with the refresh token, the previous connection should be stopped and a new connection should be created with the new token. Now I want to know how should I do this? Do I have to constantly check the token? Or should this be addressed by sending each request to the server?

@MehdiBenmoha On the close event you can check if the error string contains unauthorized and then you can restart the connection, didn't implement it yet but this is how I think it should be done — Kardon63
@Kardon63 the onclose event is triggered but the string doesn't contain unauthorized, the listener gets an undefined value. It was also very hard for me to renew the connection because I am using an async call to get the token and I am wrapping the whole system with rxJS, so the quick and dirty fix was to reload the page when a disconnected event is received, while also setting aggressive delays for automatic reconnects. — Mehdi Benmoha

Kiril1512 Kiril1512 · Accepted Answer · 2020-06-03T09:03:11

When the token will expire the connection will be droped by the server and you will have the error on the server side. I believe is the 405 error code Method now allowed that you will get.

So what you need is catch this token expiration error and drop the connection so you can start a new one with the new token.

renew token in signalR after expired token

2 Answers