Direct to another route in Angular 2 if the user is already authenticated

Question

Direct to another route in Angular 2 if the user is already authenticated

Looking at my route setup, it's structured like this:

const routes: Routes = [
  { path: '', redirectTo: '/login', pathMatch: 'full' },
  { path: 'login', component: LoginComponent },
  { path: 'dashboard', component: DashboardComponent, canActivate: [AuthGuard] },
];

On top of that, there is an AuthGuard class:

export class AuthGuard implements CanActivate, CanActivateChild {
  constructor(private router: Router,
              private authService: AuthService) { }

  canActivate() {
    if (this.authService.isLoggedIn()) {
      return true;
    }
    this.router.navigate(['login']);
    return false;
  }
}

The current behavior redirects the user to the login page upon visiting the site and prevents access to /dashboard without authentication. The objective now is to redirect a logged-in user directly to /dashboard. For instance, when logging in at myapp.com, I aim to be instantly directed to myapp.com/dashboard.

angular typescript routes

Answer 1

Answer №1

To access the resolve property in the [Route interface], you need to navigate through the available properties of a route:

export interface Route {
  path?: string;
  pathMatch?: string;
  matcher?: UrlMatcher;
  component?: Type<any>;
  redirectTo?: string;
  outlet?: string;
  canActivate?: any[];
  canActivateChild?: any[];
  canDeactivate?: any[];
  canLoad?: any[];
  data?: Data;
  resolve?: ResolveData;
  children?: Routes;
  loadChildren?: LoadChildren;
  runGuardsAndResolvers?: RunGuardsAndResolvers;
  _loadedConfig?: LoadedRouterConfig;
}

The purpose of the resolve property is to fetch certain data prior to moving on to the route. The format for the resolve function is as follows:

resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) : Observable<T>|Promise<T>|T

In this scenario, we can customize the behavior by creating an injectable class and linking it with the login route's resolve property.

@Injectable()
export class IsLoggedIn {
  constructor(
    private router: Router, 
    private authService: AuthService) {
  }

  resolve(): void {
    if (this.authService.isAuthenticated) this.router.navigate(['/dashboard'])
  }
}

Add the resolve property to your /login route definition.

{
  path: 'login',
  component: LoginComponent,
  resolve: [IsLoggedIn]
}

Import and include the class in the providers array within AppModule.

providers: [
  IsLoggedIn
]

Now, if a user who is already logged in tries to access the /login page, they will be automatically redirected to /dashboard without encountering the login screen.

Answer 2

To access the resolve property in the [Route interface], you need to navigate through the available properties of a route:

export interface Route {
  path?: string;
  pathMatch?: string;
  matcher?: UrlMatcher;
  component?: Type<any>;
  redirectTo?: string;
  outlet?: string;
  canActivate?: any[];
  canActivateChild?: any[];
  canDeactivate?: any[];
  canLoad?: any[];
  data?: Data;
  resolve?: ResolveData;
  children?: Routes;
  loadChildren?: LoadChildren;
  runGuardsAndResolvers?: RunGuardsAndResolvers;
  _loadedConfig?: LoadedRouterConfig;
}

The purpose of the resolve property is to fetch certain data prior to moving on to the route. The format for the resolve function is as follows:

resolve(route: ActivatedRouteSnapshot, state: RouterStateSnapshot) : Observable<T>|Promise<T>|T

In this scenario, we can customize the behavior by creating an injectable class and linking it with the login route's resolve property.

@Injectable()
export class IsLoggedIn {
  constructor(
    private router: Router, 
    private authService: AuthService) {
  }

  resolve(): void {
    if (this.authService.isAuthenticated) this.router.navigate(['/dashboard'])
  }
}

Add the resolve property to your /login route definition.

{
  path: 'login',
  component: LoginComponent,
  resolve: [IsLoggedIn]
}

Import and include the class in the providers array within AppModule.

providers: [
  IsLoggedIn
]

Now, if a user who is already logged in tries to access the /login page, they will be automatically redirected to /dashboard without encountering the login screen.

Answer 3

Answer №2

If faced with this situation, my approach would involve directing all traffic to the DashboardComponent by utilizing:

{path: '', redirectTo: 'dashboard', pathMatch: 'full'}

The dashboard component could then analyze whether the user is authenticated or not (given that AuthGuard is operational). If an unauthenticated user is detected, the system would automatically redirect them to the login page.

Answer 4

If faced with this situation, my approach would involve directing all traffic to the DashboardComponent by utilizing:

{path: '', redirectTo: 'dashboard', pathMatch: 'full'}

The dashboard component could then analyze whether the user is authenticated or not (given that AuthGuard is operational). If an unauthenticated user is detected, the system would automatically redirect them to the login page.

Answer 5

Answer №3

One quick solution is to make adjustments to your LoginComponent.

Assuming that the method this.authService.isLoggedIn() returns a boolean value, you can implement a check in the LoginComponent's ngOnInit function like so:

import { Component, OnInit } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';

import {AuthService} from '<path_to_your_auth_service>';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.scss'],
  providers: []
})
export class LoginComponent implements OnInit {
  constructor(
    private _route: ActivatedRoute,
    private _router: Router,
    private _authService: AuthService
  )

  ngOnInit() {
    // Retrieve return url from route parameters or set default to '/'
    this.returnUrl = this._route.snapshot.queryParams['returnUrl'] || '/';

    // CHECK THE isLoggedIn STATE HERE 
    if (this._authService.isLoggedIn()) {
      this._router.navigate([this.returnUrl]);
    }

  }

  // Include other login-related logic here

  login() { }

}

Keep in mind that this check is specifically added within ngOnInit.

if (this._authService.isLoggedIn()) {
  this._router.navigate([this.returnUrl]);
}

Answer 6

One quick solution is to make adjustments to your LoginComponent.

Assuming that the method this.authService.isLoggedIn() returns a boolean value, you can implement a check in the LoginComponent's ngOnInit function like so:

import { Component, OnInit } from '@angular/core';
import { Router, ActivatedRoute } from '@angular/router';

import {AuthService} from '<path_to_your_auth_service>';

@Component({
  selector: 'app-login',
  templateUrl: './login.component.html',
  styleUrls: ['./login.component.scss'],
  providers: []
})
export class LoginComponent implements OnInit {
  constructor(
    private _route: ActivatedRoute,
    private _router: Router,
    private _authService: AuthService
  )

  ngOnInit() {
    // Retrieve return url from route parameters or set default to '/'
    this.returnUrl = this._route.snapshot.queryParams['returnUrl'] || '/';

    // CHECK THE isLoggedIn STATE HERE 
    if (this._authService.isLoggedIn()) {
      this._router.navigate([this.returnUrl]);
    }

  }

  // Include other login-related logic here

  login() { }

}

Keep in mind that this check is specifically added within ngOnInit.

if (this._authService.isLoggedIn()) {
  this._router.navigate([this.returnUrl]);
}

Direct to another route in Angular 2 if the user is already authenticated

Answer №1

Answer №2

Answer №3

Similar questions

Troubleshooting problem with Angular Click Outside Directive and unexpected extra click event issue

How can I build TypeScript using the react-native-typescript-transformer?

Enforce directory organization and file naming conventions within a git repository by leveraging eslint

Error: The method "next" cannot be used with BehaviorSubject

Creating a setup in TypeScript to enable imports between CommonJS and ES modules (for node-fetch and Express)

What is the method to reach the DOM element of a different component in Angular?

After importing the shared module in a feature module, Angular components declared in the shared module are not being recognized in the feature modules

Tips for displaying bar chart labels effectively with ChartJS

Switch the checkbox attribute for multiple items within a carousel using Angular 2/Typescript

What is the best way to find a match for {0} while still allowing for proper

The issue of returning a boolean value in an rxjs function leading to failure

Angular2 Error: ngClass used in a Host component, "is not recognized as a valid native property"

What are the repercussions of labeling a function, TypeScript interface, or TypeScript type with export but never actually importing it? Is this considered poor practice or is there a potential consequence?

The term "primordials is not defined" is a common error

The async pipe is failing to function properly when used with the same observable

When attempting to send an archiver file in NodeJS, the request may become unresponsive

Checking radios or checkboxes will always result in a null value when retrieving their form values

Gatsby no longer hosts the website locally during certain tasks

Incorrect date being sent by Mat Date picker

What is the method of linking interdependent subscriptions that rely on multiple preceding observables?