如何在Angular等待守卫

问题描述

如果我在一条路线上指定三名警卫，似乎立即评估所有警卫。

If i specify three guards on a route, it seems as though all guards are evaluated immediately.

{path：''，component ：OptionsComponent，canActivate：[GuardOne，GuardTwo，GuardThree]}

我遇到的问题是我不想要 GuardTwo 运行直到GuardOne完成。有没有办法实现这个目标？

The problem I have is I don't want GuardTwo to run until GuardOne has finished. Is there any way to achieve this?

推荐答案

我认为这不可能在4.1.3中实现。 是运行该代码的代码警卫：

I don't think that's possible in the 4.1.3. Here is the code that runs the guards:

  private runCanActivate(future: ActivatedRouteSnapshot): Observable<boolean> {
    const canActivate = future._routeConfig ? future._routeConfig.canActivate : null;
    if (!canActivate || canActivate.length === 0) return of (true);
    const obs = map.call(from(canActivate), (c: any) => {
      const guard = this.getToken(c, future);
      let observable: Observable<boolean>;
      if (guard.canActivate) {
        observable = wrapIntoObservable(guard.canActivate(future, this.future));
      } else {
        observable = wrapIntoObservable(guard(future, this.future));
      }
      return first.call(observable);
    });
    return andObservables(obs);
  }

这个简化的部分：

// array of all guards
canActivate.map((guard)=>{
     observable = guard.canActivate()
})

按顺序运行所有警卫，无需等待之前完成。

runs all guards in a sequence without waiting for the previous to finish.

一种可能的解决方案是让一个服务实现 CanActivate 并结合其他警卫：

One possible solution would be to have one service that implements CanActivate and combines other guards:

class Combined {
  constructor(private gA: GuardA, private gB: GuardB) {}

  canActivate(r, s) {
        return gA.canActivate(r, s).then(()=>{ return gB.canActivate() });
  }
}

...
{path: '', component: OptionsComponent, canActivate: [ Combined ]}

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