Migrate to null-safety

example/lib/main.dart

@@ -3,7 +3,6 @@ import 'package:flutter/services.dart';
 import 'dart:async';
 import 'package:msal_flutter/msal_flutter.dart';
 
-
 void main() => runApp(MyApp());
 
 class MyApp extends StatefulWidget {
@@ -12,22 +11,26 @@ class MyApp extends StatefulWidget {
 }
 
 class _MyAppState extends State<MyApp> {
-
-  static const String _authority = "https://msalfluttertest.b2clogin.com/tfp/msalfluttertest.onmicrosoft.com/B2C_1_sisu";
+  static const String _authority =
+      "https://msalfluttertest.b2clogin.com/tfp/msalfluttertest.onmicrosoft.com/B2C_1_sisu";
   static const String _clientId = "5913dfb1-7576-451c-a7ea-a7c5a3f8682a";
-  
+
   String _output = 'NONE';
 
   PublicClientApplication pca;
 
-  Future<void> _acquireToken() async{
-    if(pca == null){
-      pca = await PublicClientApplication.createPublicClientApplication(_clientId, authority: _authority);
+  Future<void> _acquireToken() async {
+    if (pca == null) {
+      pca = await PublicClientApplication.createPublicClientApplication(
+          _clientId,
+          authority: _authority);
     }
 
     String res;
-    try{
-      res = await pca.acquireToken(["https://msalfluttertest.onmicrosoft.com/msalbackend/user_impersonation"]);
+    try {
+      res = await pca.acquireToken([
+        "https://msalfluttertest.onmicrosoft.com/msalbackend/user_impersonation"
+      ]);
     } on MsalUserCancelledException {
       res = "User cancelled";
     } on MsalNoAccountException {
@@ -36,7 +39,7 @@ class _MyAppState extends State<MyApp> {
       res = "invalid config";
     } on MsalInvalidScopeException {
       res = "Invalid scope";
-    }on MsalException {
+    } on MsalException {
       res = "Error getting token. Unspecified reason";
     }
 
@@ -46,14 +49,17 @@ class _MyAppState extends State<MyApp> {
   }
 
   Future<void> _acquireTokenSilently() async {
-    if(pca == null){
-      pca = await PublicClientApplication.createPublicClientApplication(_clientId, authority: _authority);
+    if (pca == null) {
+      pca = await PublicClientApplication.createPublicClientApplication(
+          _clientId,
+          authority: _authority);
     }
-    
+
     String res;
-    try
-    {
-      res = await pca.acquireTokenSilent(["https://msalfluttertest.onmicrosoft.com/msalbackend/user_impersonation"]);
+    try {
+      res = await pca.acquireTokenSilent([
+        "https://msalfluttertest.onmicrosoft.com/msalbackend/user_impersonation"
+      ]);
     } on MsalUserCancelledException {
       res = "User cancelled";
     } on MsalNoAccountException {
@@ -62,7 +68,7 @@ class _MyAppState extends State<MyApp> {
       res = "invalid config";
     } on MsalInvalidScopeException {
       res = "Invalid scope";
-    }on MsalException {
+    } on MsalException {
       res = "Error getting token silently!";
     }
 
@@ -73,23 +79,25 @@ class _MyAppState extends State<MyApp> {
 
   Future _logout() async {
     print("called logout");
-    if(pca == null){
-      pca = await PublicClientApplication.createPublicClientApplication(_clientId, authority: _authority);
+    if (pca == null) {
+      pca = await PublicClientApplication.createPublicClientApplication(
+          _clientId,
+          authority: _authority);
     }
 
     print("pca is not null");
     String res;
-    try{
+    try {
       await pca.logout();
       res = "Account removed";
     } on MsalException {
       res = "Error signing out";
-    } on PlatformException catch (e){
+    } on PlatformException catch (e) {
       res = "some other exception ${e.toString()}";
     }
 
     print("setting state");
-    setState((){
+    setState(() {
       _output = res;
     });
   }
@@ -104,13 +112,15 @@ class _MyAppState extends State<MyApp> {
         body: Center(
           child: Column(
             children: <Widget>[
-              RaisedButton( onPressed: _acquireToken, 
-                child: Text('AcquireToken()'),),
-              RaisedButton( onPressed: _acquireTokenSilently,
-                child: Text('AcquireTokenSilently()')),
-              RaisedButton( onPressed: _logout,
-                child: Text('Logout')),
-              Text( _output),
+              RaisedButton(
+                onPressed: _acquireToken,
+                child: Text('AcquireToken()'),
+              ),
+              RaisedButton(
+                  onPressed: _acquireTokenSilently,
+                  child: Text('AcquireTokenSilently()')),
+              RaisedButton(onPressed: _logout, child: Text('Logout')),
+              Text(_output),
             ],
           ),
         ),

lib/src/msal_exception.dart

@@ -1,39 +1,61 @@
 class MsalException implements Exception {
-  String errorMessage;
-  MsalException(this.errorMessage);
+  final String errorMessage;
+
+  const MsalException(this.errorMessage);
 }
 
 class MsalChangedClientIdException extends MsalException {
-  MsalChangedClientIdException()
-      : super(
-            "Cannot create a client with a new client ID. Only 1 client id supported");
+  const MsalChangedClientIdException()
+      : super("Cannot create a client with a new client ID. "
+            "Only 1 client id supported");
+
+  static MsalChangedClientIdException create() =>
+      const MsalChangedClientIdException();
 }
 
 class MsalUserCancelledException extends MsalException {
-  MsalUserCancelledException() : super("User cancelled login request");
+  const MsalUserCancelledException() : super("User cancelled login request");
+
+  static MsalUserCancelledException create() =>
+      const MsalUserCancelledException();
 }
 
 class MsalNoAccountException extends MsalException {
-  MsalNoAccountException()
+  const MsalNoAccountException()
       : super("Cannot login silently. No account available");
+
+  static MsalNoAccountException create() =>
+      const MsalNoAccountException();
 }
 
 class MsalInvalidConfigurationException extends MsalException {
-  MsalInvalidConfigurationException(errorMessage) : super(errorMessage);
+  const MsalInvalidConfigurationException(String errorMessage) : super(errorMessage);
+
+  static MsalInvalidConfigurationException create(String errorMessage) =>
+      MsalInvalidConfigurationException(errorMessage);
 }
 
 class MsalInvalidScopeException extends MsalException {
-  MsalInvalidScopeException() : super("Invalid or no scope");
+  const MsalInvalidScopeException() : super("Invalid or no scope");
+
+  static MsalInvalidScopeException create() =>
+      const MsalInvalidScopeException();
 }
 
 class MsalInitializationException extends MsalException {
-  MsalInitializationException()
-      : super(
-            "Error initializing client. Please ensure correctly configuration supplied");
+  const MsalInitializationException()
+      : super("Error initializing client. Please ensure "
+            "correctly configuration supplied");
+
+  static MsalInitializationException create() =>
+      const MsalInitializationException();
 }
 
 class MsalUninitializedException extends MsalException {
-  MsalUninitializedException()
-      : super(
-            "Client not initialized. Client must be initialized before attempting to use");
+  const MsalUninitializedException()
+      : super("Client not initialized. Client "
+            "must be initialized before attempting to use");
+
+  static MsalUninitializedException create() =>
+      const MsalUninitializedException();
 }

lib/src/public_client_application.dart

@@ -1,109 +1,72 @@
 import 'dart:async';
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 import 'msal_exception.dart';
 
 /// Represents a PublicClientApplication used to authenticate using the implicit flow
+@immutable
 class PublicClientApplication {
   static const MethodChannel _channel = const MethodChannel('msal_flutter');
 
-  String _clientId, _authority;
+  final String _clientId;
+  final String? _authority;
 
-  /// Create a new PublicClientApplication authenticating as the given [clientId],
-  /// optionally against the selected [authority], defaulting to the common
-  PublicClientApplication(String clientId, {String authority}) {
-    throw Exception(
-        "Direct call is no longer supported in v1.0, please use static method createPublicClientApplication");
-  }
-
-  PublicClientApplication._create(String clientId, {String authority}) {
-    _clientId = clientId;
-    _authority = authority;
-  }
+  const PublicClientApplication._create(this._clientId, {String? authority})
+      : _authority = authority;
 
   static Future<PublicClientApplication> createPublicClientApplication(
-      String clientId,
-      {String authority}) async {
-    var res = PublicClientApplication._create(clientId, authority: authority);
+    String clientId, {
+    String? authority,
+  }) async {
+    final res = PublicClientApplication._create(clientId, authority: authority);
     await res._initialize();
     return res;
   }
 
   /// Acquire a token interactively for the given [scopes]
-  Future<String> acquireToken(List<String> scopes) async {
-    //create the arguments
-    var res = <String, dynamic>{'scopes': scopes};
-
-    //call platform
-    try {
-      final String token = await _channel.invokeMethod('acquireToken', res);
-      return token;
-    } on PlatformException catch (e) {
-      throw _convertException(e);
-    }
-  }
+  Future<String> acquireToken(List<String> scopes) =>
+      _invokePlatformMethod<String>('acquireToken', {'scopes': scopes});
 
   /// Acquire a token silently, with no user interaction, for the given [scopes]
-  Future<String> acquireTokenSilent(List<String> scopes) async {
-    //create the arguments
-    var res = <String, dynamic>{'scopes': scopes};
+  Future<String> acquireTokenSilent(List<String> scopes) =>
+      _invokePlatformMethod('acquireTokenSilent', {'scopes': scopes});
 
-    //call platform
-    try {
-      final String token =
-          await _channel.invokeMethod('acquireTokenSilent', res);
-      return token;
-    } on PlatformException catch (e) {
-      throw _convertException(e);
-    }
-  }
+  Future<void> logout() => _invokePlatformMethod('logout');
+
+  // initialize the main client platform side
+  Future<void> _initialize() async => _invokePlatformMethod(
+        'initialize',
+        <String, dynamic>{
+          'clientId': this._clientId,
+          //if authority has been set, add it as well
+          if (this._authority != null) 'authority': this._authority
+        },
+      );
 
-  Future logout() async {
+  Future<T> _invokePlatformMethod<T>(String method,
+      [Map<String, dynamic> arguments = const {}]) async {
     try {
-      await _channel.invokeMethod('logout', <String, dynamic>{});
+      return await _channel.invokeMethod(method, arguments);
     } on PlatformException catch (e) {
       throw _convertException(e);
     }
   }
 
-  MsalException _convertException(PlatformException e) {
-    switch (e.code) {
-      case "CANCELLED":
-        return MsalUserCancelledException();
-      case "NO_SCOPE":
-        return MsalInvalidScopeException();
-      case "NO_ACCOUNT":
-        return MsalNoAccountException();
-      case "NO_CLIENTID":
-        return MsalInvalidConfigurationException("Client Id not set");
-      case "INVALID_AUTHORITY":
-        return MsalInvalidConfigurationException("Invalid authroity set.");
-      case "CONFIG_ERROR":
-        return MsalInvalidConfigurationException(
-            "Invalid configuration, please correct your settings and try again");
-      case "NO_CLIENT":
-        return MsalUninitializedException();
-      case "CHANGED_CLIENTID":
-        return MsalChangedClientIdException();
-      case "INIT_ERROR":
-        return MsalInitializationException();
-      case "AUTH_ERROR":
-      default:
-        return MsalException("Authentication error");
-    }
-  }
-
-  //initialize the main client platform side
-  Future _initialize() async {
-    var res = <String, dynamic>{'clientId': this._clientId};
-    //if authority has been set, add it aswell
-    if (this._authority != null) {
-      res["authority"] = this._authority;
-    }
+  static final _exceptionMapping = <String, MsalException Function()>{
+    "CANCELLED": MsalUninitializedException.create,
+    "NO_SCOPE": MsalInvalidScopeException.create,
+    "NO_ACCOUNT": MsalNoAccountException.create,
+    "NO_CLIENT": MsalUninitializedException.create,
+    "CHANGED_CLIENTID": MsalChangedClientIdException.create,
+    "INIT_ERROR": MsalInitializationException.create,
+    "NO_CLIENTID": () => MsalInvalidConfigurationException("Client Id not set"),
+    "INVALID_AUTHORITY": () =>
+        MsalInvalidConfigurationException("Invalid authroity set."),
+    "CONFIG_ERROR": () => MsalInvalidConfigurationException(
+        "Invalid configuration, please correct your settings and try again"),
+  };
 
-    try {
-      await _channel.invokeMethod('initialize', res);
-    } on PlatformException catch (e) {
-      throw _convertException(e);
-    }
-  }
+  MsalException _convertException(PlatformException e) =>
+      _exceptionMapping[e.code]?.call() ??
+      MsalException("Authentication error");
 }