Wait until a subscribe is called in angular

Question

Good morning, I created an angualr app and I need to check users role in routing. I created a service "RoleGuardService" with a method canLoad that read the JWS token and check the user permission:

import * as JWT from 'jwt-decode';
...
   const tokenPayload: App = JWT(token);
   if(tokenPayload.UserType == expectedRole){
      return true;
   }
   return false;

So far so good, but this force me to declare the permission hard coded:

{ path: 'xxx', component: yyy, canLoad: [RoleGuardService], data: { expectedRole: 'Admin' } },

Is possible to create a method that requires authorization directly from the web API? like:

    var isAllowed = false;
    this.http.get('https://xxx/check_user/').subscribe(result: bool) => {
        isAllowed = result;
    }
    ///wait until the subscribe is called
    return isAllowed;

Answer 1

You can use the canActivate parameter for route from Core angular which has been created for that type of usecase https://angular.io/api/router/CanActivate

exmaple:

  {
    path: 'protectedRoute',
    component: SecureComponent,
    data: {
      authorities: ['ROLE_ADMIN'],
    },
    canActivate: [UserRouteAccessService]
  }





@Injectable({ providedIn: 'root' })
export class UserRouteAccessService implements CanActivate {
  constructor(
    private router: Router,
    private accountService: AccountService,
  ) {}

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Observable<boolean> {
    const authorities = route.data['authorities'];
    return this.accountService.identity().pipe(
      map(account => {
        if (!account) {
          return false;
        }

        if (!authorities || authorities.length === 0) {
          return true;
        }

        const hasAnyAuthority =   authorities.some((authority: string) => account.authorities.includes(authority));
        if (hasAnyAuthority) {
          return true;
        }
        this.router.navigate(['accessdenied']);
        return false;
      })
    );
  }

}

where AccountService is your service to get current login user

Answer 2

You can make canLoad to return Observable of type boolean (Observable<boolean>)and return something like -

return this.http.get('https://xxx/check_user/').map(result => result);