问题描述
我已经为我的angular2 rc5应用程序创建了身份验证保护.
I have created an authentication guard for my angular2 rc5 application.
我也在使用redux存储.在该商店中，我保留用户的身份验证状态.
I am also using a redux store. In that store I keep the user's authentication state.
我了解到，守卫可以返回可观察到的承诺( https://angular.io/docs/ts/latest/guide/router.html#!#guards )
I read that the guard can return an observable or promise (https://angular.io/docs/ts/latest/guide/router.html#!#guards)
我似乎无法找到一种方法来让警卫队等到更新，并且只有此后更新后才能返回警卫队，因为默认值的商店永远都是假的.
I can't seem to find a way for the guard to wait until the store/observable is updated and only after that update return the guard because the default value of the store will always be false.
第一次尝试:
@Injectable()
export class AuthGuard implements CanActivate {
@select(['user', 'authenticated']) authenticated$: Observable<boolean>;
constructor() {}
canActivate(): Promise<boolean> {
return new Promise((resolve, reject) => {
// updated after a while ->
this.authenticated$.subscribe((auth) => {
// will only reach here after the first update of the store
if (auth) { resolve(true); }
// it will always reject because the default value
// is always false and it takes time to update the store
reject(false);
});
});
}
}
第二次尝试:
@Injectable()
export class AuthGuard implements CanActivate {
@select(['user', 'authenticated']) authenticated$: Observable<boolean>;
constructor() {}
canActivate(): Promise<boolean> {
return new Promise((resolve, reject) => {
// tried to convert it for single read since canActivate is called every time. So I actually don't want to subscribe here.
let auth = this.authenticated$.toPromise();
auth.then((authenticated) => {
if (authenticated) { resolve(true); }
reject(false);
});
auth.catch((err) => {
console.log(err);
});
}
}
推荐答案
订阅不会返回Observable.但是，您可以像这样使用地图运算符:
Subscribe doesn't return an Observable.However, you can use the map operator like that:
this.authenticated$.map(
authenticated => {
if(authenticated) {
return true;
}
return false;
}
).first() // or .take(1) to complete on the first event emit
这篇关于如何在Angular 2 Guards的canActivate()中使用可观察对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！