Executing an HTTP POST request within an Angular 7 route guard: A step-by-step guide

Question

Executing an HTTP POST request within an Angular 7 route guard: A step-by-step guide

In my Angular 7 application, I have implemented a route guard that is dependent on the response of a post call. The guard is structured like this:

canActivate = (_router: ActivatedRouteSnapshot): boolean => {
    console.log('in link expiry guard')
    let userEmail = _router.paramMap.get('email');
    let isAllow;

    console.log('params : ', userEmail)
    userEmail = this._utilityService.decryptMsgByCryptoJs(userEmail);
    console.log('user email : ', userEmail)
    this._dataService.post(this._const.userResetPasswordLinkExpiry, { email: userEmail }).subscribe(resp => {
        console.log('verify response : ',resp)
        if (resp.success) {
            console.log('in success')
            isAllow = true;
        } else {
            isAllow = false;
        }
    })
    console.log('allow flag  : ',isAllow)
    if (isAllow) {
        console.log('in allow')
        return true;
    } else {
        console.log('in not allow')
        this._utilityService.navigate('/login');
        this._dataService.exhangeResetPasswordObsMsg({ event: 'linkExpired' });
        return false;
    }
}

The issue arises when the HTTP post call is still in progress and the guard executes completely, returning false. This leads to complications as the response from the post call arrives later. How can I handle this situation effectively so that the route can be determined based on the post call response?

angular typescript angular-route-guards

Answer 1

Answer №1

If you wish to execute an Http request within your canActivate method, you must return an Observable<boolean> instead of a simple boolean. This is necessary because the action is asynchronous.

Moreover, if you want to redirect in case of failure, you should return

Observable<boolean | UrlTree>

instead.

Basic Implementation

constructor(private router: Router) { }

canActivate(route: ActivatedRouteSnapshot, 
    state: RouterStateSnapshot): Observable<boolean | UrlTree> {
  return this.http.post(url, body).pipe(
    map((resp: any) => resp.success ? true : this.router.parseUrl('/path'))
  );   
}

In this example, we return the observable http request (which will be invoked by the router through subscription), and based on the response, either:

true - allowing the router to proceed to the protected route
UrlTree - instructing the router to navigate to a specific route

Application in Your Scenario

To apply this concept in your scenario, additional steps are required within the pipe due to the presence of an extra service call.

// TODO: inject other services
constructor(private router: Router) { }

canActivate(route: ActivatedRouteSnapshot, 
      state: RouterStateSnapshot): Observable<boolean | UrlTree> {
    const userEmail = route.paramMap.get('email');

    // Assuming this is a synchronous operation
    userEmail = this._utilityService.decryptMsgByCryptoJs(userEmail);

    const url = this._const.userResetPasswordLinkExpiry;
    const body = { email: userEmail };

    return this._dataService.post(url, body).pipe(
      // initial mapping of response to true/false
      map((resp: any) => resp.success),

      // trigger an action if false
      tap(success => {
        if (!success) {
          // Synchronous assumption here. Use switchMap for async
          this._dataService.exhangeResetPasswordObsMsg({ event: 'linkExpired' });
        }
      }),
      // final mapping to boolean | UrlTree
      map(success => success ? true : this.router.parseUrl('/login'))
    );   
}

This code includes some assumed synchronous service calls. It illustrates how to handle asynchronous operations within the canActivate function and decide whether to allow navigation or choose an alternative route.

Answer 2

If you wish to execute an Http request within your canActivate method, you must return an Observable<boolean> instead of a simple boolean. This is necessary because the action is asynchronous.

Moreover, if you want to redirect in case of failure, you should return

Observable<boolean | UrlTree>

instead.

Basic Implementation

constructor(private router: Router) { }

canActivate(route: ActivatedRouteSnapshot, 
    state: RouterStateSnapshot): Observable<boolean | UrlTree> {
  return this.http.post(url, body).pipe(
    map((resp: any) => resp.success ? true : this.router.parseUrl('/path'))
  );   
}

In this example, we return the observable http request (which will be invoked by the router through subscription), and based on the response, either:

true - allowing the router to proceed to the protected route
UrlTree - instructing the router to navigate to a specific route

Application in Your Scenario

To apply this concept in your scenario, additional steps are required within the pipe due to the presence of an extra service call.

// TODO: inject other services
constructor(private router: Router) { }

canActivate(route: ActivatedRouteSnapshot, 
      state: RouterStateSnapshot): Observable<boolean | UrlTree> {
    const userEmail = route.paramMap.get('email');

    // Assuming this is a synchronous operation
    userEmail = this._utilityService.decryptMsgByCryptoJs(userEmail);

    const url = this._const.userResetPasswordLinkExpiry;
    const body = { email: userEmail };

    return this._dataService.post(url, body).pipe(
      // initial mapping of response to true/false
      map((resp: any) => resp.success),

      // trigger an action if false
      tap(success => {
        if (!success) {
          // Synchronous assumption here. Use switchMap for async
          this._dataService.exhangeResetPasswordObsMsg({ event: 'linkExpired' });
        }
      }),
      // final mapping to boolean | UrlTree
      map(success => success ? true : this.router.parseUrl('/login'))
    );   
}

This code includes some assumed synchronous service calls. It illustrates how to handle asynchronous operations within the canActivate function and decide whether to allow navigation or choose an alternative route.

Executing an HTTP POST request within an Angular 7 route guard: A step-by-step guide

Answer №1

Basic Implementation

Application in Your Scenario

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