AngularFire2取消订阅未注册订阅时的注销,数据库权限错误

Question

我在这里使用AngularFire2版本的代码,我用它来从我的一个组件上的数据库中获取一些成员.

当我在同一个组件中调用此注销时,我遇到了问题.我取消订阅订阅但我仍然在控制台中收到错误说Exception was thrown by user callback. Error: permission_denied at /users/uid.我知道这是因为我不再登录,我的数据库规则不允许这种读取操作.如果我已经取消订阅,我不知道为什么它还在尝试读取数据.

    constructor(private afAuth: AngularFireAuth, private db: AngularFireDatabase) {
        this.user = afAuth.authState;

        this.userSub = this.user.subscribe(auth => {
            if (auth) {
                this.member = db.object('/users/' + auth.uid);
                this.dbSub = this.member.subscribe();
            }
        });
    }

    logout() {
        this.dbSub.unsubscribe();
        this.userSub.unsubscribe();

        this.afAuth.auth.signOut()
            .then(() => this.router.navigateByUrl('/login'));
    }

Answer 1

您可以尝试使用RxJS主题以及运算符takeUntil()来帮助确保在以下情况之前清除observable signOut():

import { Subject } from 'rxjs/Subject';
import 'rxjs/add/operator/takeUntil';

export class Foo {
    private ngUnsubscribe: Subject<void> = new Subject<void>();

    constructor(private afAuth: AngularFireAuth, private db: AngularFireDatabase) {
        this.user = afAuth.authState;

        this.userSub = this.user.subscribe(auth => {
            if (auth) {
                this.member = db.object('/users/' + auth.uid);

                this.dbSub = this.member
                    .takeUntil(ngUnsubscribe)
                    .subscribe(results => console.log(results));
            }
        });
    }

    logout() {
        this.ngUnsubscribe.next();
        this.ngUnsubscribe.complete();

        this.userSub.unsubscribe();

        this.afAuth.auth.signOut()
            .then(() => this.router.navigateByUrl('/login'));
    }
}

希望这有帮助!