Skip to main content

Angular 5 Redirect if not logged in - CanActivate AuthGuard

In this article, I will discuss how to redirect one page to other page and also discuss how to use the AuthGuard and CanActivate in Angular 5 applications.

Three options are available to redirect page in Angular 5 –
1.      Imperatively redirect the user in AppComponent
2.      Use the route data property
3.      Use a CanActivate guard

The AuthGuard should call an application service that can login a user and retain information about the current user.

Options 1 – Imperatively redirect the user in AppComponent
@Component({
  selector: 'app-root',
  template: `.....`
})
export class AppComponent {
  constructor(private _authService: AuthService, _router: Router) {
    if (_authService.isLoggedIn()) {
      _router.navigate(['user']);
    }
  }
}
This is not good practice and I will not recommend using this options.

Options 2 - Use the route data property
This is the best solution and used by many expert programmers. You can simply add some metadata in the routes declaration to indicate that - “this route requires that the user must be loggedIn”.

const APPROUTES: Routes = [
    {path: 'dashboard', component: AppComponent, data:{requiresLogin: true}},
    {path: 'user', component: UserComponent, data:{requiresLogin: true}}
];
This is the best approach to redirect if not logged in and I will recommend to this option.

Options 3 -Use a CanActivate guard
Firstly add a CanActivate guard to all the routes that require the user to be logged in and my guard is called AuthGuard and see the following example –

@NgModule({
  declarations: [
    AppComponent,
    LoginComponent,
    UserComponent
  ],
  imports: [
    BrowserModule,
    FormsModule,
    HttpClientModule,
    RouterModule.forRoot([
      { path: '', component: AppComponent, pathMatch: 'full', canActivate: [AuthGuard]},
      { path: 'user', component: UserComponent, canActivate: [AuthGuard]},
      { path: 'login', component: LoginComponent}])
  ],
  providers: [EmployeeService, ValidationService,
          AuthenticationService, UserService],
  bootstrap: [AppComponent]
})
export class AppModule { }


And
import { Injectable } from '@angular/core';
import { CanActivate, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { Observable } from 'rxjs/Observable';
import {Router} from '@angular/router';
import { AuthServiceService } from './auth-service.service';

@Injectable()
export class AuthGuard implements CanActivate {

  //constructor initialization
  constructor(private authService: AuthServiceService,   private route: Router){  }

  //can Activate Route
  canActivate(
    next: ActivatedRouteSnapshot,
    state: RouterStateSnapshot): Observable<boolean> | Promise<boolean> | boolean {
      if(this.authService.isLoggednIn()){
        this.route.navigate(["user"]);
        return true;
      }else{
        return false;
      }
  }
}

This is also best approach to redirect if not logged in and this one is also recommend to this option.
I hope you are enjoying with this post! Please share with you friends! Thank you!!

Labels

Labels:
By Anil Singh | Rating of this article (*****)

Popular posts from this blog

List of Countries, Nationalities and their Code In Excel File

Download JSON file for this List - Click on JSON file    Countries List, Nationalities and Code Excel ID Country Country Code Nationality Person 1 UNITED KINGDOM GB British a Briton 2 ARGENTINA AR Argentinian an Argentinian 3 AUSTRALIA AU Australian an Australian 4 BAHAMAS BS Bahamian a Bahamian 5 BELGIUM BE Belgian a Belgian 6 BRAZIL BR Brazilian a Brazilian 7 CANADA CA Canadian a Canadian 8 CHINA CN Chinese a Chinese 9 COLOMBIA CO Colombian a Colombian 10 CUBA CU Cuban a Cuban 11 DOMINICAN REPUBLIC DO Dominican a Dominican 12 ECUADOR EC Ecuadorean an Ecuadorean 13 EL SALVA...
Read more

nullinjectorerror no provider for httpclient angular 17

In Angular 17 where the standalone true option is set by default, the app.config.ts file is generated in src/app/ and provideHttpClient(). We can be added to the list of providers in app.config.ts Step 1:   To provide HttpClient in a standalone app we could do this in the app.config.ts file, app.config.ts: import { ApplicationConfig } from '@angular/core'; import { provideRouter } from '@angular/router'; import { routes } from './app.routes'; import { provideClientHydration } from '@angular/platform-browser'; //This (provideHttpClient) will help us to resolve the issue  import {provideHttpClient} from '@angular/common/http'; export const appConfig: ApplicationConfig = {   providers: [ provideRouter(routes),  provideClientHydration(), provideHttpClient ()      ] }; The appConfig const is used in the main.ts file, see the code, main.ts : import { bootstrapApplication } from '@angular/platform-browser'; import { appConfig } from ...
Read more

Encryption and Decryption Data/Password in Angular

You can use crypto.js to encrypt data. We have used 'crypto-js'.   Follow the below steps, Steps 1 –  Install CryptoJS using below NPM commands in your project directory npm install crypto-js --save npm install @types/crypto-js –save After installing both above commands it looks like  – NPM Command  1 ->   npm install crypto-js --save NPM Command  2 ->   npm install @types/crypto-js --save Steps 2  - Add the script path in “ angular.json ” file. "scripts" : [                "../node_modules/crypto-js/crypto-js.js"               ] Steps 3 –  Create a service class “ EncrDecrService ” for  encrypts and decrypts get/set methods . Import “ CryptoJS ” in the service for using  encrypt and decrypt get/set methods . import  {  Injectable  }  from ...
Read more

How To convert JSON Object to String?

To convert JSON Object to String - To convert JSON Object to String in JavaScript using “JSON.stringify()”. Example – let myObject =[ 'A' , 'B' , 'C' , 'D' ] JSON . stringify ( myObject ); ü   Stayed Informed –   Object Oriented JavaScript Interview Questions I hope you are enjoying with this post! Please share with you friends!! Thank you!!!
Read more

Cache Busting with Angular and Angular CLI

Cache Busting -  Run the below command in your project directory - ng build -- prod The above command is used to enable cache busting by default with Angular CLI. This command can take a few minutes based on your project size. Stayed Informed – Angular 4 and Angular 5 Documents Steps for Cache busting with Angular and Angular CLI - ·          C:\Users\Viaindia>d: ·          D:\>cd Angular ·          D:\Angular>cd PipeApps ·          D:\Angular\PipeApps>ng serve --open ** NG Live Development Server is listening on localhost:4200, open your browser on http://localhost:4200/ **  10% building modules 8/10 modules 2 active ...e}!D:\Angular\PipeApps\src\styles.csswebpack: wait until bundle finished: /            ...
Read more