auth token interceptor

Author: aguskoll

modules/data/lib/init.dart

@@ -11,6 +11,7 @@ import 'package:get_it/get_it.dart';
 import 'package:shared_preferences/shared_preferences.dart';
 
 import 'network/config/environment_service_impl.dart';
+import 'network/interceptors/auth_token_interceptor.dart';
 
 class DataInit {
   static Future<void> initialize(GetIt getIt) async {
@@ -19,15 +20,16 @@ class DataInit {
     getIt.registerSingleton<SharedPreferences>(pref);
     getIt.registerSingleton<Preferences>(PreferencesImpl(getIt()));
 
-    //Network
-    getIt.registerLazySingleton<Dio>(() => NetworkConfig.provideDio());
+    // Network
+    getIt.registerLazySingleton<AuthTokenInterceptor>(() => AuthTokenInterceptor(getIt()));
+    getIt.registerLazySingleton<Dio>(() => NetworkConfig.provideDio(getIt()));
     getIt.registerLazySingleton<EnvironmentService>(() => EnvironmentServiceImpl(getIt()));
 
-    //Data Sources
+    // Data Sources
 
-    //Repositories
+    // Repositories
     getIt.registerLazySingleton<AuthRepository>(
-          () => AuthRepositoryImpl(getIt(), getIt()),
+          () => AuthRepositoryImpl(getIt(),),
     );
     getIt.registerLazySingleton<CommonRepository>(
           () => CommonRepositoryImpl(getIt()),

modules/data/lib/network/config/network_config.dart

@@ -2,10 +2,11 @@ import 'package:dio/dio.dart';
 import 'package:domain/env/env_config.dart';
 import 'package:flutter/foundation.dart';
 
+import '../interceptors/auth_token_interceptor.dart';
 import 'network_constants.dart';
 
 class NetworkConfig {
-  static Dio provideDio() {
+  static Dio provideDio(AuthTokenInterceptor? authTokenInterceptor) {
     final options = BaseOptions(
       baseUrl: EnvConfig.apiUrl,
       connectTimeout: const Duration(
@@ -30,6 +31,10 @@ class NetworkConfig {
       ));
     }
 
+    if (authTokenInterceptor != null) {
+      dio.interceptors.add(authTokenInterceptor);
+    }
+
     return dio;
   }
 

modules/data/lib/network/config/network_constants.dart

@@ -4,4 +4,10 @@ class NetworkConstants {
   //static const baseUrl =  String.fromEnvironment('API_URL', defaultValue: "NA");
   static const productsPath = "/products";
   static const baseUrl =  "http://www.example.com"; // To get started: comment this and uncomment line 4
+  static const tokenHeader = "token";
+  static const unauthorizedStatusCode = 401;
+  static const forbiddenStatusCode = 403;
+  static const invalidStatusCode = 422;
+  static const contentTypeHeader = "Content-Type";
+  static const applicationJsonContentType = "application/json";
 }

modules/data/lib/network/interceptors/auth_token_interceptor.dart

@@ -0,0 +1,52 @@
+import 'package:dio/dio.dart';
+
+import '../../preferences/preferences.dart';
+import '../config/network_constants.dart';
+
+class AuthTokenInterceptor extends Interceptor {
+  final Preferences _preferences;
+
+  AuthTokenInterceptor(this._preferences);
+
+  @override
+  Future<void> onRequest(
+    RequestOptions options,
+    RequestInterceptorHandler handler,
+  ) async {
+    try {
+      final token = _preferences.getToken();
+      if (token != null && token.isNotEmpty) {
+        options.headers.addAll(
+          {
+            NetworkConstants.tokenHeader: token,
+            NetworkConstants.contentTypeHeader:
+                NetworkConstants.applicationJsonContentType,
+          },
+        );
+      } else {
+        await _clearCredentials();
+      }
+    } catch (_) {
+      await _clearCredentials();
+    }
+    return super.onRequest(options, handler);
+  }
+
+  @override
+  void onError(DioException err, ErrorInterceptorHandler handler) {
+    try {
+      if (err.response?.statusCode == NetworkConstants.unauthorizedStatusCode ||
+          err.response?.statusCode == NetworkConstants.forbiddenStatusCode ||
+          err.response?.statusCode == NetworkConstants.invalidStatusCode) {
+        _clearCredentials();
+      }
+    } catch (_) {
+      _clearCredentials();
+    }
+    super.onError(err, handler);
+  }
+
+  Future<void> _clearCredentials() async {
+    _preferences.clear();
+  }
+}

modules/data/lib/preferences/preferences.dart

@@ -14,4 +14,6 @@ abstract class Preferences {
   Future<void> setAppTheme(String theme);
 
   Future<void> setToken(String? token);
+
+  Future<void> clear();
 }

modules/data/lib/preferences/preferences_impl.dart

@@ -43,4 +43,9 @@ class PreferencesImpl extends Preferences {
     if (token == null) return _pref.remove(_tokenKey);
     return _pref.setString(_tokenKey, token);
   }
+
+  @override
+  Future<void> clear() {
+    return _pref.clear();
+  }
 }

modules/data/lib/repositories/auth_repository_impl.dart

@@ -28,6 +28,6 @@ class AuthRepositoryImpl implements AuthRepository {
 
   @override
   Future<void> logout() async {
-    _preferences.setToken(null);
+    _preferences.clear();
   }
 }