3

基本上一切正常，直到由于某种原因输入 url 时，方法 canActivate 中的变量 this.estado 恰好未定义。

我认为这是因为构造函数没有在正确的时间获得 observable。 

import { Component, Injectable, Inject, OnInit } from '@angular/core';
import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';


@Injectable()
export class AuthService implements CanActivate {
  myAppUrl: string;
  estado: any;

  constructor(private router: Router, private http: HttpClient, @Inject('BASE_URL') private baseUrl: string) {
    this.myAppUrl = baseUrl;
    this.estadoSetUp(); /* If I put hear this.estado = true everything works fine */
  }

  public getJSON(): Observable<any> {
    return this.http.get(this.myAppUrl + 'api/IsAuthenticated');
  }

  public estadoSetUp() {
    this.getJSON().subscribe(data => {
      this.estado = data.AmILoggin;
    });
  }

  canActivate(): Observable<boolean> {
    if (this.estado != true) {
      this.router.navigate(['/']);
    }

    return this.estado;
  }
}

感谢@sirdieter 解决了

我把解决方案留给将来遇到麻烦的人： 

import { Component, Injectable, Inject, OnInit } from '@angular/core';
import { Router, CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot       } from '@angular/router';
import { HttpClient } from '@angular/common/http';
import { Observable } from 'rxjs/Observable';
import { ReplaySubject } from 'rxjs/ReplaySubject'
import 'rxjs/add/operator/map';
import 'rxjs/add/operator/catch';
import 'rxjs/add/observable/throw';
import 'rxjs/add/operator/do';

@Injectable()
export class AuthService implements CanActivate {
  myAppUrl: string;
  private isAuthorized = new ReplaySubject<boolean>(1);

  constructor(private router: Router, private http: HttpClient,     @Inject('BASE_URL') private baseUrl: string) {
    this.myAppUrl = baseUrl;
    this.estadoSetUp();
  }

  public getJSON(): Observable<any> {
    return this.http.get(this.myAppUrl + 'api/IsAuthenticated');
  }

  public estadoSetUp() {
    this.getJSON().subscribe(data => {
      this.isAuthorized.next(data.AmILoggin);
    });
  }

  canActivate(): Observable<boolean> {
    return this.isAuthorized.asObservable()
      .do(auth => {
        if (auth != true) {
          this.router.navigate(['/']);
        }
      });
  }
}

4

2 回答 2

2

请注意，您的 http 调用是异步的，

因此，当您直接打开一个 URL 时，会构造这个守卫（它会启动 http 调用），然后很快（毫秒）就会调用“canActivate”。结果，如果您的 http 调用不够快，则您的变量没有定义，因为 http 调用没有结果。

canActivate 返回一个布尔值的 Observable。因此，一种解决方案是将变量 estado 更改为可观察的

于 2018-07-17T10:58:53.617 回答
1

您正确地发现了问题。您可以返回 http 调用 observable 并将其映射到 AmILoggin 属性。（RxJS 6 语法，你好像有 5 个）

canActivate(): Observable<boolean> {
    return this.getJSON().pipe(pluck('AmILoggin');
}

但在这种情况下，您将在每次调用 canActivate() 时进行 http 调用；要只有一个 http 调用，您可以使用主题：

private isAuthorized = new ReplaySubject<boolean>(1);

public estadoSetup() {
    this.getJSON().subscribe(data => this.isAuthorized.next(data.AmILoggin));
}
// RxJS 6
canActivate() {
    return this.isAuthorized.asObservable().pipe(
      tap(auth => {
        if (auth) {
            this.router.navigate(['/']);
        }
      }
    );
}
// RxJS 5
canActivate(): Observable<boolean>
    return this.isAuthorized.asObservable()
    .do(auth => {
        if (auth) {
            this.router.navigate(['/']);
        }
    });
于 2018-07-17T11:05:03.727 回答