MSAL Auth

Microsoft Authentication 🔐 Library for Flutter.

msal_auth plugin provides Microsoft authentication in Android and iOS devices using native MSAL library. This is very straightforward and easy to use.

Platform Support

Android	iOS	macOS
SDK 21+	14+	10.15+

Features 🚀

• Option to set one of the following broker (Authentication middleware):
  • MS Authenticator App
  • Browser
  • In-App WebView
• Single & Multiple account mode support
• Supports different identity providers (authority):
  • AAD (Microsoft Entra ID)
  • B2C (Business to customer)
• Acquire token interactively & silently
• Option to set login hint & prompt type in acquiring token
• Complete authentication result with account information

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To implement MSAL in Flutter, you first need to set up an app in the Azure Portal and configure certain platform-specific settings.

➡ Follow the step-by-step guide below ⬇️

Create an App in Azure Portal

• First, sign up and create an app on the Azure Portal.

• To create the app, search for App registrations, click on it, and navigate to New registration.

• Fill in the Name field, select the Supported account types, and register the app.

• Once the application is created, you will see the Application (client) ID and Directory (tenant) ID. These values are required in your Dart code.

  

• Next, you need to add platform-specific configurations for Android and iOS/macOS in the Azure Portal. To do this, navigate to Manage > Authentication > Add platform.

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Android Setup - Azure portal

For Android, You need to provide package name and signature hash. To generate a signature hash in Flutter, use the below command from your project's android folder:

• Debug:

  keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -storepass android -keypass android | openssl sha1 -binary | openssl base64

• Release:

  keytool -exportcert -alias upload -keystore app/upload-keystore.jks | openssl sha1 -binary | openssl base64

  • Ensure you have upload-keystore.jks file placed inside android/app folder. Follow the Flutter's documentation Build and release an Android app to create a release setup.

Register both signature hash in Azure's Android Platform configurations.

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iOS/macOS Setup - Azure portal

• You need to provide only Bundle ID of your iOS/macOS app. Redirect URI will be generated automatically by system.

  

That's it for the Azure portal configuration.

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Please follow the platform configuration ⬇️ before jump to the Dart code.

Android Configuration

This plugin offers full customization, allowing you to provide a configuration JSON file to be used during application creation & authentication.

Follow the steps below to complete the Android configuration.

Creating MSAL Configuration JSON

• Create an msal_config.json file in the /assets folder of your project and copy the JSON content from the Microsoft default configuration file.

• Obtain the redirect_uri from the Azure Portal. This URI is required in the Android configuration when creating the public client application using Dart code.

• The redirect URI typically follows this format for Android:

  msauth://<APP_PACKAGE_NAME>/<BASE64_ENCODED_PACKAGE_SIGNATURE>
  

• Android redirect URI from Azure Portal:

  

There is no need to include client_id and redirect_uri in this JSON, as they will be added programmatically by the Dart code when the public client application is created.

---

Setup Account Mode

To support single account mode in Android, declare the following in a configuration file:

"account_mode": "SINGLE"

For multiple mode:

"account_mode": "MULTIPLE"

---

Setup Authority

Follow the Android MSAL Authority documentation to configure it in various ways, depending on your application's requirements.

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Setup Broker (Authentication Middleware) (Optional)

• Set broker authentication (authenticate user by Microsoft Authenticator App)

  "broker_redirect_uri_registered": true

  • If the Authenticator app is not installed on the Android device, the authorization_user_agent configuration will be used for authentication.

• Authenticate using Browser

  "broker_redirect_uri_registered": false,
  "authorization_user_agent": "BROWSER"

• Authenticate using WebView

  "broker_redirect_uri_registered": false,
  "authorization_user_agent": "WEBVIEW"

---

Add Internet and Network State permission in AndroidManifest.xml

This permission declaration is required for browser-delegated authentication:

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

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Add BrowserTabActivity in AndroidManifest.xml

If you use Browser or Authenticator app for authentication, you must specify BrowserTabActivity within the <application> tag in your AndroidManifest.xml file.

<application>
...

  <activity android:name="com.microsoft.identity.client.BrowserTabActivity">
      <intent-filter>
          <action android:name="android.intent.action.VIEW" />

          <category android:name="android.intent.category.DEFAULT" />
          <category android:name="android.intent.category.BROWSABLE" />

          <data
              android:host="com.example.msal_auth_example"
              android:path="/<BASE64_ENCODED_PACKAGE_SIGNATURE>"
              android:scheme="msauth" />
      </intent-filter>
  </activity>
    
</application>

• Replace host with your app's package name and path with the base64 signature hash that was generated earlier.
• To load debug and release signature hash programmatically in your project, follow the example README and example code.

To learn more about configuring JSON, follow Android MSAL configuration.

ProGuard

You don't need to include any rules for MSAL Android library as this is done using consumer-rules.pro file within this Flutter plugin.

For more info regarding ProGuard, follow Android App Optimization.

iOS Configuration

• Add a new keychain group com.microsoft.adalcache to your project capabilities.

  

Without this configuration, your app will not be able to open the Microsoft Authenticator app if specified in the broker. Additionally, the logout method will throw an exception because it will not be able to find the account in the cache.

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Info.plist Modification

• Add your application's redirect URI scheme to your Info.plist file:

  <key>CFBundleURLTypes</key>
  <array>
    <dict>
        <key>CFBundleURLSchemes</key>
        <array>
            <string>msauth.$(PRODUCT_BUNDLE_IDENTIFIER)</string>
        </array>
    </dict>
  </array>

• Add LSApplicationQueriesSchemes to use the Microsoft Authenticator app as a broker for authentication. Not required when Safari Browser or WebView is used as a broker.

  <key>LSApplicationQueriesSchemes</key>
  <array>
      <string>msauthv2</string>
      <string>msauthv3</string>
  </array>

  • If you use Broker.msAuthenticator after declaring the above schemes but the Authenticator app is not installed on the iPhone, the authentication will fall back to using Safari Browser.

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Handle callback from MSAL

• Your app needs to handle login success callback if app uses Microsoft Authenticator app OR Safari Browser for authentication. WebView does not require it.
• Your app needs to handle the login success callback if it uses the Microsoft Authenticator app or Safari Browser for authentication. WebView does not require this callback.

AppDelegate.swift

import MSAL

override func application(_ app: UIApplication, open url: URL, options: [UIApplication.OpenURLOptionsKey : Any] = [:]) -> Bool {
      return MSALPublicClientApplication.handleMSALResponse(url, sourceApplication: options[UIApplication.OpenURLOptionsKey.sourceApplication] as? String)
}

• Refer to the AppDelegate.swift file in the example app for more clarity.

• If you adopted UISceneDelegate on iOS 13+, MSAL callback needs to be placed into the appropriate delegate method of UISceneDelegate instead of AppDelegate.

SceneDelegate.swift

import MSAL

func scene(_ scene: UIScene, openURLContexts URLContexts: Set<UIOpenURLContext>) {
        
  guard let urlContext = URLContexts.first else {
    return
  }
        
  let url = urlContext.url
  let sourceApp = urlContext.options.sourceApplication
        
  MSALPublicClientApplication.handleMSALResponse(url, sourceApplication: sourceApp)
}

See more info on iOS MSAL configuration.

macOS Configuration

• Add a new keychain group com.microsoft.identity.universalstorage to your project capabilities.

  

• If you encounter the NSPOSIXErrorDomain error while using acquireToken in a macOS debug app, it indicates a missing network entitlement required for the app in debug mode. To fix this issue, add the following configuration to the DebugProfile.entitlements file:

  <key>com.apple.security.network.client</key>
  <true/>

Code Implementation 👨‍💻

This section covers how to write the Dart code to set up an MSAL application in Flutter and authenticate the user.

Create Public Client Application

Create the public client app based on your account mode. usually, it is a single account mode.

final msalAuth = await SingleAccountPca.create(
  clientId: '<MICROSOFT_CLIENT_ID>',
  androidConfig: AndroidConfig(
    configFilePath: 'assets/msal_config.json',
    redirectUri: '<Android Redirect URI>',
  ),
  appleConfig: AppleConfig(
    authority: '<Optional, but must be provided for b2c>',
    // Change authority type to 'b2c' for business to customer flow.
    authorityType: AuthorityType.aad,
    // Change broker if you need. Applicable only for iOS platform.
    broker: Broker.msAuthenticator,
  ),
);

• By default, login will be attempted to AAD (Microsoft Entra ID). if you want to use B2C, set the authorityType to AuthorityType.b2c.

• To modify value of authority in iOS/macOS, follow Configure iOS/macOS authority.

• On iOS, if the broker is set to AuthMiddleware.msAuthenticator and the Authenticator app is not installed on the device, it will fall back to using Safari Browser for authentication.

---

Acquire Token (Login to Microsoft Account)

This method opens the Microsoft login page in the specified broker and provides the authentication result upon a successful login. The result includes the accessToken.

final authResult = await publicClientApplication.acquireToken(
  scopes: <String>[
    'https://graph.microsoft.com/user.read',
    // Add other scopes here if required.
  ],
  // UI option for authentication, default is [Prompt.whenRequired]
  prompt: Prompt.login,
  // Provide 'loginHint' if you have.
  loginHint: '<Email Id / Username / Unique Identifier>',
  // Optional: Custom authority URL for B2C or different
  // tenant scenarios
  authority: '<Authority URL>',
);

log('Auth result: ${authResult.toJson()}');

---

Acquire Token by Silent Call 🔇

Typically, this method should be called when the accessToken expires. It uses the refresh token from the cached account, performs authentication in the background, and returns the authentication result, similar to the acquireToken() method.

The app can store the expiresOn value of the AuthenticationResult in the preferences and check the following condition before using the accessToken:

if (expiresOn.isBefore(DateTime.now())) {
  final authResult = await publicClientApplication.acquireTokenSilent(
    scopes: <String>[], // List of string same as "acquireToken()"
    identifier: 'Account Identifier, required for multiple account mode',
    // Authority URL where you want to refresh tokens using
    // a different policy than the original authentication.
    // Required for B2C scenarios.
    authority: '<Authority URL>',
  );

  log('Auth result: ${authResult.toJson()}');
  // Store new value of "expiresOn" or entire "authResult" object.
}

This method can throw an MsalUiRequiredException if the refresh token has expired or does not exist. In this case, the acquireToken() method should typically be called to prompt the user for interactive authentication and obtain a new access token.

try {
  acquireTokenSilent();
} on MsalException catch (e) {
  if (e is MsalUiRequiredException) {
    await acquireToken();
    // Handle auth result
  }
}

All other types of exceptions are optional to handle, depending on your use case.

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Exception Handling 🚨

All MSAL exceptions thrown by the Android and iOS/macOS platforms can be handled on the Dart side. You can manage them according to your use case, such as by logging the errors, displaying user-friendly messages, retrying the operation, or triggering specific app behaviors based on the type of exception.

You can learn more about MSAL exceptions - Android and MSAL exceptions - iOS/macOS.

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Setup Example App 📱

The example app demonstrates all the features supported by this plugin with providing a practical implementation.

See the example README for detailed setup instructions.