Use a router guard to protect routes from unauthorized users and show a snackbar error message.
Steps
Step 1 - Generate the Guard
command line
ng g guard user/auth
auth.guard.ts
import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { AngularFireAuth } from '@angular/fire/auth';
import { SnackService } from '../services/snack.service';
@Injectable({
providedIn: 'root'
})
export class AuthGuard implements CanActivate {
constructor(
private afAuth: AngularFireAuth,
private snack: SnackService
) {}
async canActivate(
next: ActivatedRouteSnapshot,
state: RouterStateSnapshot
): Promise<boolean> {
const user = await this.afAuth.currentUser;
const isLoggedIn = !!user;
if (!isLoggedIn) {
this.snack.authError();
}
return isLoggedIn;
}
}Step 2 - Show a SnackBar
Generate a global service that can be used to show snack bar message from any component.
command line
ng g service services/snack
snack.service.ts
import { Injectable } from '@angular/core';
import { Router } from '@angular/router';
import { MatSnackBar } from '@angular/material/snack-bar';
import { tap } from 'rxjs/operators';
@Injectable({
providedIn: 'root'
})
export class SnackService {
constructor(private snackBar: MatSnackBar, private router: Router) {}
authError() {
this.snackBar.open('You must be logged in!', 'OK', {
duration: 5000
});
return this.snackBar._openedSnackBarRef
.onAction()
.pipe(
tap(_ =>
this.router.navigate(['/login'])
)
)
.subscribe();
}
}