fix/refactor/simplify powersync auth setup

Author: Dieterbe

lib/api_client.dart

@@ -14,32 +14,6 @@ class ApiClient {
 
   const ApiClient(this.baseUrl);
 
-  Future<Map<String, dynamic>> authenticate(String username, String password) async {
-    final response = await http.post(
-      Uri.parse('$baseUrl/api/v2/login/'),
-      headers: {'Content-Type': 'application/json'},
-      body: json.encode({'username': username, 'password': password}),
-    );
-    if (response.statusCode == 200) {
-      log.log(Level.ALL, response.body);
-      return json.decode(response.body);
-    }
-    throw Exception('Failed to authenticate');
-  }
-
-  Future<Map<String, dynamic>> getWgerJWTToken() async {
-    final response = await http.post(
-      Uri.parse('$baseUrl/api/v2/token'),
-      headers: {HttpHeaders.contentTypeHeader: 'application/json'},
-      body: json.encode({'username': 'admin', 'password': 'adminadmin'}), // FIXME
-    );
-    if (response.statusCode == 200) {
-      log.log(Level.ALL, response.body);
-      return json.decode(response.body);
-    }
-    throw Exception('Failed to fetch token');
-  }
-
   /// Returns a powersync JWT token token
   ///
   /// Note that at the moment we use the permanent API token for authentication

lib/main.dart

@@ -77,11 +77,6 @@ void main() async {
   // Needs to be called before runApp
   WidgetsFlutterBinding.ensureInitialized();
 
-  await openDatabase();
-
-  final loggedIn = await isLoggedIn();
-  print('main(): is logged in $loggedIn');
-
   // Locator to initialize exerciseDB
   await ServiceLocator().configure();
   print('running myapp');

lib/powersync.dart

@@ -3,7 +3,6 @@ import 'package:logging/logging.dart';
 import 'package:path/path.dart';
 import 'package:path_provider/path_provider.dart';
 import 'package:powersync/powersync.dart';
-import 'package:shared_preferences/shared_preferences.dart';
 import 'package:wger/api_client.dart';
 
 import './app_config.dart';
@@ -37,6 +36,7 @@ class DjangoConnector extends PowerSyncBackendConnector {
     // https://docs.powersync.com/usage/installation/authentication-setup/custom
     // final wgerSession = await apiClient.getWgerJWTToken();
     final session = await apiClient.getPowersyncToken();
+    // note: we don't set userId and expires property here. not sure if needed
     return PowerSyncCredentials(endpoint: AppConfig.powersyncUrl, token: session['token']);
   }
 
@@ -86,37 +86,24 @@ late final PowerSyncDatabase db;
 // Hacky flag to ensure the database is only initialized once, better to do this with listeners
 bool _dbInitialized = false;
 
-/// id of the user currently logged in
-Future<String?> getUserId() async {
-  final prefs = await SharedPreferences.getInstance();
-  return prefs.getString('id');
-}
-
-Future<bool> isLoggedIn() async {
-  final userId = await getUserId();
-  return userId != null;
-}
-
 Future<String> getDatabasePath() async {
   final dir = await getApplicationSupportDirectory();
   return join(dir.path, 'powersync-demo.db');
 }
 
 // opens the database and connects if logged in
-Future<void> openDatabase() async {
+Future<void> openDatabase(bool connect) async {
   // Open the local database
   if (!_dbInitialized) {
     db = PowerSyncDatabase(schema: schema, path: await getDatabasePath(), logger: attachedLogger);
     await db.initialize();
     _dbInitialized = true;
   }
 
-  DjangoConnector? currentConnector;
-
-  if (await isLoggedIn()) {
+  if (connect) {
     // If the user is already logged in, connect immediately.
     // Otherwise, connect once logged in.
-    currentConnector = DjangoConnector(db);
+    final currentConnector = DjangoConnector(db);
     db.connect(connector: currentConnector);
 
     // TODO: should we respond to login state changing? like here:

lib/providers/auth.dart

@@ -182,6 +182,7 @@ class AuthProvider with ChangeNotifier {
     }
 
     // Log user in
+    // should we update the backend to just include a powersync token also?
     token = responseData['token'];
     notifyListeners();
 

lib/screens/home_tabs_screen.dart

@@ -54,8 +54,8 @@ class _HomeTabsScreenState extends State<HomeTabsScreen> with SingleTickerProvid
   void initState() {
     super.initState();
 
-    final authProvider = context.read<AuthProvider>();
-    print('auth provider says surverurl is ${authProvider.serverUrl}');
+    // do we need to await this? or if it's async, how do we handle failures?
+    _setupPowersync();
 
     // Loading data here, since the build method can be called more than once
     _initialData = _loadEntries();
@@ -75,19 +75,27 @@ class _HomeTabsScreenState extends State<HomeTabsScreen> with SingleTickerProvid
     const GalleryScreen(),
   ];
 
-  /// Load initial data from the server
-  Future<void> _loadEntries() async {
+  Future<void> _setupPowersync() async {
+    final authProvider = context.read<AuthProvider>();
+    print('auth provider says surverurl is ${authProvider.serverUrl}');
+    await openDatabase(false);
+
     final connector = DjangoConnector(db);
     try {
+      // TODO: should we cache these credentials? that's what their demo does?
+      // we could maybe get the initial token from the /api/v2/login call
       final credentials = await connector.fetchCredentials();
       print('----------');
       print(credentials);
       print('----------');
+      await openDatabase(true);
     } catch (e) {
       print('fail' + e.toString());
     }
-    final loggedIn = await isLoggedIn();
-    print('_loadEntries(): is logged in $loggedIn');
+  }
+
+  /// Load initial data from the server
+  Future<void> _loadEntries() async {
     final authProvider = context.read<AuthProvider>();
 
     if (!authProvider.dataInit) {