Can you cancel a navigation within the NavController?

Ionic Framework ionic-v3
1

Authentication is tricky for me because at any point, due to third parties involved, the server can decline my request and I’d have to get a new token and authenticate again (don’t ask, it’s not my server). Preferably I would have done this check using Angular 2 CanActivate route guard, but seeing how Ionic 2 doesn’t quite support this yet, I’m thinking of just subscribing to the NavController viewWillEnter event. Here’s what I have so far.

import { Service } from './services/oauth';
@Component({
    templateUrl: 'build/app.html'
})
export class App {
    @ViewChild(Nav) nav: Nav;
    rootPage: any = InboxPage;

    constructor(public platform: Platform) {
        this.init();
    }

    init() {
        this.platform.ready().then(() => {
            StatusBar.styleDefault();

            this.nav.viewWillEnter.subscribe(data => {
                console.log('viewWillEnter', data);

                if (!Service.isAuthenticated && data.name !== "LoginPage") {
                    debugger; //now what? How do you cancel? return false?
                }

            });
        });
    }
    }
2

when are you getting authenticated in this code ? Anyways, how about ?

rootPage: any;

init() {
  if (!Service.isAuthenticated) { 
     rootPage = LoginPage;
  }
  else {
     rootPage = InboxPage;
  }
}

does that work ? Or am I missing the point ?

3

I’m porting an Angular 1.3 app, and the logic for authentication is handled as a resolve function for all the routes in the router config.

What you have can work initially. The challenge I have is that the user can lose their authentication while they’re using the app. I need to be able to detect when that happens, re-authenticate the user, and the re-submit their failed requests.

4

I’m on the same issue. Have you resolved the problem?

5

Not yet, I was looking at the source code, and it appears that the NavController just emits the observable. No code to handle a return value or preventDefault() call. Seems like they would need to implement this.

6

So it’s possible to create some new level of abstraction which will manage ability of going to some page