How to Ensure Initial Authentication with Azure AD in Angular App using Guards and NGRX

What are Guards and NGRX?

Before we dive into the implementation, let’s cover some essential concepts:

Guards

In Angular, guards are a type of route guard that allows or denies access to a route based on certain conditions. In our case, we’ll use guards to ensure that users are authenticated with Azure AD before accessing our app’s routes.

Think of guards as bouncers at a nightclub. They check if you’re on the guest list (i.e., authenticated) before letting you in.

NGRX

NGRX is a state management library for Angular that helps you manage your app’s state in a predictable and scalable way. We’ll use NGRX to store and retrieve the user’s authentication token, which is required for Azure AD authentication.

Imagine NGRX as a secure vault where you store your app’s sensitive data, including the user’s authentication token.

Setting up Azure AD and Azure AD Authentication

Before we start coding, let’s set up Azure AD and Azure AD authentication:

1. Create an Azure AD tenant and register your app.
2. Register a new application in Azure AD and configure the app’s settings.
3. Create a client secret and store it securely (e.g., in an environment variable).
4. Install the `@azure/msal-browser` package using npm or yarn.
5. Configure the `@azure/msal-browser` package with your Azure AD tenant ID and client ID.

For a step-by-step guide on setting up Azure AD and Azure AD authentication, refer to the official Microsoft documentation.

Implementing Initial Authentication with Guards and NGRX

Now that we have Azure AD set up, let’s implement initial authentication with guards and NGRX:

Step 1: Create an NGRX Store

Create a new file called `auth.reducers.ts` and add the following code:

import { createReducer } from '@ngrx/store';
import { initialState } from './auth.state';

const authReducer = createReducer(
  initialState,
  {
    // Add authentication token to the store
    ADD_AUTH_TOKEN: (state, { token }) => ({ ...state, token }),
    // Remove authentication token from the store
    REMOVE_AUTH_TOKEN: (state) => ({ ...state, token: null }),
  }
);

export function reducer(state = initialState, action) {
  return authReducer(state, action);
}

Step 2: Create an NGRX Effect

Create a new file called `auth.effects.ts` and add the following code:

import { Injectable } from '@angular/core';
import { Actions, ofType, createEffect } from '@ngrx/effects';
import { tap, exhaustMap, map, catchError } from 'rxjs/operators';
import { of } from 'rxjs';
import {AzureADAuthService} from '../azure-ad-auth.service';

@Injectable()
export class AuthEffects {
  // Initialize the authentication service
  constructor(private actions$: Actions, private azureADAuthService: AzureADAuthService) {}

  // Create an effect to authenticate with Azure AD
  authenticate$ = createEffect(
    () => this.actions$.pipe(
      ofType('[Auth] Authenticate'),
      exhaustMap(() => {
        return this.azureADAuthService.authenticate().pipe(
          map((response) => {
            // Add the authentication token to the store
            return { type: '[Auth] Add Token', token: response.accessToken };
          }),
          catchError((error) => of({ type: '[Auth] Authentication Failed', error })),
        );
      }),
    ),
    { dispatch: true }
  );
}

Step 3: Create an Azure AD Authentication Service

Create a new file called `azure-ad-auth.service.ts` and add the following code:

import { Injectable } from '@angular/core';
import { PublicClientApplication } from '@azure/msal-browser';

@Injectable({
  providedIn: 'root'
})
export class AzureADAuthService {
  private clientApp: PublicClientApplication;

  constructor() {
    // Initialize the Azure AD client application
    this.clientApp = new PublicClientApplication(
      'your_azure_ad_tenant_id',
      'https://login.microsoftonline.com/' + 'your_azure_ad_tenant_id'
    );
  }

  // Authenticate with Azure AD
  authenticate(): Promise {
    return this.clientApp.acquireTokenSilent({
      scopes: ['https://graph.microsoft.com/.default'],
    }).then((response) => {
      return response.accessToken;
    });
  }
}

Step 4: Create a Guard

Create a new file called `auth.guard.ts` and add the following code:

import { Injectable } from '@angular/core';
import { CanActivate, Router, ActivatedRouteSnapshot, RouterStateSnapshot } from '@angular/router';
import { Store } from '@ngrx/store';
import { select, selectSnapshot } from '@ngrx/store';
import { selectAuthToken } from '../auth.selectors';

@Injectable({
  providedIn: 'root'
})
export class AuthGuard implements CanActivate {
  constructor(private store: Store, private router: Router) {}

  canActivate(route: ActivatedRouteSnapshot, state: RouterStateSnapshot): Promise<boolean> {
    return this.store.select(selectAuthToken).toPromise().then((token) => {
      if (!token) {
        // Redirect to login page if no authentication token is found
        this.router.navigate(['/login']);
        return false;
      }
      return true;
    });
  }
}

Putting it All Together

Now that we’ve implemented the NGRX store, effect, Azure AD authentication service, and guard, let’s put it all together:

1. Add the `AuthGuard` to your app’s routes:

import { NgModule } from '@angular/core';

import { RouterModule, Routes } from '@angular/router';

import { AuthGuard } from './auth.guard';

const routes: Routes = [

  {

    path: '',

    canActivate: [AuthGuard],

    children: [

      // Add your app's routes here

    ]

  }

];
@NgModule({

  imports: [RouterModule.forRoot(routes)],

  exports: [RouterModule]

})

export class AppRoutingModule {}

2. In your app component, dispatch the authentication action:

import { Component, OnDestroy, OnInit } from '@angular/core';

import { Store } from '@ngrx/store';

import { select, selectSnapshot } from '@ngrx/store';

import { authActionTypes } from './auth.actions';

@Component({

  selector: 'app-root',

  template: '<router-outlet></router-outlet>'

})

export class AppComponent implements OnInit, OnDestroy {

  constructor(private store: Store) {}
  ngOnInit(): void {

    // Dispatch the authentication action

    this.store.dispatch({ type: '[Auth] Authenticate' });

  }

}

That's it! You've successfully implemented initial authentication with Azure AD in your Angular app using guards and NGRX. Your app is now secure and protected against unauthorized access.

Conclusion

In this comprehensive guide, we've covered the importance of Azure AD, the role of guards and NGRX in Angular, and the step-by-step process of implementing initial authentication with Azure AD using guards and NGRX. By following these instructions, you can ensure that your Angular app is secure, scalable, and protected against unauthorized access.

Remember to stay vigilant and monitor your app's authentication and authorization mechanisms regularly to prevent any potential security breaches.

Further Reading

If you want to dive deeper into Azure AD, guards, and NGRX, here are some recommended resources:

• Azure AD documentation: https://docs.microsoft.com/en-us/Here are 5 questions and answers about how to ensure initial authentication with Azure AD in an Angular app using guards and NGRX:
  

  Frequently Asked Questions

  Get ready to unlock the secrets of securing your Angular app with Azure AD authentication!

  How do I set up Azure AD authentication in my Angular app?

  To set up Azure AD authentication in your Angular app, you'll need to register your app in Azure AD, install the required packages (e.g., `@azure/msal-angular`), and configure the authentication module in your app. You'll also need to add the Azure AD credentials to your environment files and update your app's routing to protect routes with Azure AD authentication.

  What is the purpose of an Authentication Guard in Angular?

  An Authentication Guard in Angular is a special type of route guard that checks whether the user is authenticated before allowing access to a specific route. If the user is not authenticated, the guard redirects them to the login page. This ensures that only authenticated users can access protected routes in your app.

  Why do I need to use NGRX with Azure AD authentication in my Angular app?

  NGRX is a state management library that helps you manage your app's state, including authentication state. By using NGRX with Azure AD authentication, you can store and manage the user's authentication state in a centralized way, making it easier to handle authentication flows and errors in your app.

  How do I handle initial authentication with Azure AD using a guard in my Angular app?

  To handle initial authentication with Azure AD using a guard, you'll need to create an authentication guard that checks whether the user is authenticated on app startup. If the user is not authenticated, the guard should redirect them to the Azure AD login page. Once the user authenticates, the guard should store the authentication token and redirect them to the protected route.

  What is the best way to store and manage authentication tokens in my Angular app?

  The best way to store and manage authentication tokens in your Angular app is to use a token storage service, such as `localStorage` or `sessionStorage`, to store the tokens securely. You should also use a token interceptor to handle token refresh and revocation, ensuring that your app stays authenticated even when the token expires.

  Let me know if you need anything else!

  Share this:

  Related posts:

  • 

    Organizing an Azure ML project with multiple step scripts and shared modules: A Step-by-Step Guide