Tutorial: Create an Angular application and prepare it for authentication

Άρθρο
11/11/2024

After registration is complete, an Angular project can be created using Angular CLI (Command Line Interface). This tutorial demonstrates how to create a single-page Angular application using the Angular CLI and create files needed for authentication and authorization.

In this tutorial:

Create a new Angular project
Configure the settings for the application
Add authentication code to the application

Prerequisites

Completion of the prerequisites and steps in Tutorial: Register an application.
Install Agular CLI
Install Node.js.
Visual Studio Code

Create a new Angular project

To build the Angular project from scratch, follow these steps:

Open a terminal window and run the following command to create a new Angular project:
```
ng new msal-angular-tutorial --routing=true --style=css --strict=false
```
The command creates a new Angular project named msal-angular-tutorial with routing enabled, CSS for styling, and strict mode disabled.
Change to the project directory:
```
cd msal-angular-tutorial
```
Install app dependencies:
```
npm install @azure/msal-browser @azure/msal-angular bootstrap
```
The command npm install @azure/msal-browser @azure/msal-angular bootstrap installs the Azure MSAL browser, Azure MSAL Angular, and Bootstrap packages.
Open angular.json and add Bootstrap's CSS path to the styles array:
```
"styles": [
    "src/styles.css",
    "node_modules/bootstrap/dist/css/bootstrap.min.css"
],
```
The code adds the Bootstrap CSS to the styles array in the angular.json file.
Generate Home and Profile components:
```
ng generate component home
ng generate component profile
```
The commands generate the Home and Profile components in the Angular project.

Remove unnecessary files and code from the project:

rm src/app/app.component.css
rm src/app/app.component.spec.ts
rm src/app/home/home.component.css
rm src/app/home/home.component.spec.ts
rm src/app/profile/profile.component.css
rm src/app/profile/profile.component.spec.ts

The commands remove unnecessary files and code from the project.

Rename app.routes.ts to app-routing.module.ts using Visual Studio Code and update all references of app.routes.ts throughout the application.
Rename app.config.ts to app.module.ts using Visual Studio Code and update all references to app.config.ts throughout the application.

After you complete these steps, the project structure should look like:

.
├── README.md
├── angular.json
├── package-lock.json
├── package.json
├── src
│   ├── app
│   │   ├── app-routing.module.ts
│   │   ├── app.component.html
│   │   ├── app.component.ts
│   │   ├── app.module.ts
│   │   ├── home
│   │   │   ├── home.component.html
│   │   │   └── home.component.ts
│   │   └── profile
│   │       ├── profile.component.html
│   │       └── profile.component.ts
│   ├── index.html
│   ├── main.ts
│   ├── polyfills.ts
│   └── styles.css
├── tsconfig.app.json
└── tsconfig.json

Configure the settings for the application

We'll use the values recorded during the app registration to configure the application for authentication. Follow these steps:

Open the src/app/app.module.ts file and replace the contents with the following code:

// Required for Angular multi-browser support
import { BrowserModule } from '@angular/platform-browser';

// Required for Angular
import { NgModule } from '@angular/core';

// Required modules and components for this application
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { ProfileComponent } from './profile/profile.component';
import { HomeComponent } from './home/home.component';

// HTTP modules required by MSAL
import { HTTP_INTERCEPTORS, HttpClientModule } from '@angular/common/http';

// Required for MSAL
import { IPublicClientApplication, PublicClientApplication, InteractionType, BrowserCacheLocation, LogLevel } from '@azure/msal-browser';
import { MsalGuard, MsalInterceptor, MsalBroadcastService, MsalInterceptorConfiguration, MsalModule, MsalService, MSAL_GUARD_CONFIG, MSAL_INSTANCE, MSAL_INTERCEPTOR_CONFIG, MsalGuardConfiguration, MsalRedirectComponent } from '@azure/msal-angular';

const isIE = window.navigator.userAgent.indexOf('MSIE ') > -1 || window.navigator.userAgent.indexOf('Trident/') > -1;

export function MSALInstanceFactory(): IPublicClientApplication {
  return new PublicClientApplication({
    auth: {
      // 'Application (client) ID' of app registration in the Microsoft Entra admin center - this value is a GUID
      clientId: "Enter_the_Application_Id_Here",
      // Full directory URL, in the form of https://login.microsoftonline.com/<tenant>
      authority: "https://login.microsoftonline.com/Enter_the_Tenant_Info_Here",
      // Must be the same redirectUri as what was provided in your app registration.
      redirectUri: "http://localhost:4200",
    },
    cache: {
      cacheLocation: BrowserCacheLocation.LocalStorage,
      storeAuthStateInCookie: isIE
    }
  });
}

// MSAL Guard is required to protect routes and require authentication before accessing protected routes
export function MSALGuardConfigFactory(): MsalGuardConfiguration {
  return { 
    interactionType: InteractionType.Redirect,
    authRequest: {
      scopes: ['user.read']
    }
  };
}

// Create an NgModule that contains the routes and MSAL configurations
@NgModule({
  declarations: [
    AppComponent,
    HomeComponent,
    ProfileComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule,
    MsalModule
  ],
  providers: [
    {
      provide: HTTP_INTERCEPTORS,
      useClass: MsalInterceptor,
      multi: true
    },
    {
      provide: MSAL_INSTANCE,
      useFactory: MSALInstanceFactory
    },
    {
      provide: MSAL_GUARD_CONFIG,
      useFactory: MSALGuardConfigFactory
    },
    {
      provide: MSAL_INTERCEPTOR_CONFIG,
      useFactory: MSALInterceptorConfigFactory
    },
    MsalService,
    MsalGuard,
    MsalBroadcastService
  ],
  bootstrap: [AppComponent, MsalRedirectComponent]
})
export class AppModule { }

The code sets up MSAL for user authentication and API protection. It configures the app with MsalInterceptor to secure API requests and MsalGuard to protect routes, while defining key components and services for authentication. Replace the following values with the values from the Microsoft Entra admin center.

Replace Enter_the_Application_Id_Here with the Application (client) ID from the app registration.
Replace Enter_the_Tenant_Info_Here with the Directory (tenant) ID from the app registration.

Save the file.

Add authentication code to the application

To handle user authentication and session management using MSAL Angular, you'll need to update src/app/app.component.ts.

Open src/app/app.component.ts file and replace the contents with the following code:

// Required for Angular
import { Component, OnInit, Inject, OnDestroy } from '@angular/core';

// Required for MSAL
import { MsalService, MsalBroadcastService, MSAL_GUARD_CONFIG, MsalGuardConfiguration } from '@azure/msal-angular';
import { EventMessage, EventType, InteractionStatus, RedirectRequest } from '@azure/msal-browser';

// Required for RJXS
import { Subject } from 'rxjs';
import { filter, takeUntil } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html'
})
export class AppComponent implements OnInit, OnDestroy {
  title = 'Angular - MSAL Example';
  loginDisplay = false;
  tokenExpiration: string = '';
  private readonly _destroying$ = new Subject<void>();

  constructor(
    @Inject(MSAL_GUARD_CONFIG) private msalGuardConfig: MsalGuardConfiguration,
    private authService: MsalService,
    private msalBroadcastService: MsalBroadcastService
  ) { }

  // On initialization of the page, display the page elements based on the user state
  ngOnInit(): void {
    this.msalBroadcastService.inProgress$
        .pipe(
        filter((status: InteractionStatus) => status === InteractionStatus.None),
        takeUntil(this._destroying$)
      )
      .subscribe(() => {
        this.setLoginDisplay();
      });

      // Used for storing and displaying token expiration
      this.msalBroadcastService.msalSubject$.pipe(filter((msg: EventMessage) => msg.eventType === EventType.ACQUIRE_TOKEN_SUCCESS)).subscribe(msg => {
      this.tokenExpiration=  (msg.payload as any).expiresOn;
      localStorage.setItem('tokenExpiration', this.tokenExpiration);
    });
  }

  // If the user is logged in, present the user with a "logged in" experience
  setLoginDisplay() {
    this.loginDisplay = this.authService.instance.getAllAccounts().length > 0;
  }

  // Log the user in and redirect them if MSAL provides a redirect URI otherwise go to the default URI
  login() {
    if (this.msalGuardConfig.authRequest) {
      this.authService.loginRedirect({ ...this.msalGuardConfig.authRequest } as RedirectRequest);
    } else {
      this.authService.loginRedirect();
    }
  }

  // Log the user out
  logout() {
    this.authService.logoutRedirect();
  }

  ngOnDestroy(): void {
    this._destroying$.next(undefined);
    this._destroying$.complete();
  }
}

The code integrates MSAL with Angular to manage user authentication. It listens for sign in status changes, displays the sign in state, handles token acquisition events, and provides methods to log users in or out based on Microsoft Entra configuration.

Save the file.

Next steps

Tutorial: Add sign in and sign out functional components in an Angular app

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