Updated readme to allow an local-only setup. Improved schema switching comment.

Author: Chriztiaan

demos/local-only-todolist/.gitignore

@@ -44,7 +44,4 @@ app.*.map.json
 /android/app/release
 
 # asdf
-.tool-versions
-
-# secrets
-app_config.dart
+.tool-versions

demos/local-only-todolist/README.md

@@ -2,15 +2,19 @@
 
 This demo app is an extension of the Flutter Todo List App that demonstrates how to use the PowerSync SDK for Flutter in an local only way. It allows the user to use the app offline without having to sign in. After signing in data that was kept locally is synced up. For a step-by-step guide, see [here](https://docs.powersync.com/integration-guides/supabase).
 
-# Running the app
+# Running the app with local-only
 
+Note that if Supabase and PowerSync credentials have not been been configured, a user will not be able to login or sign up. There is a hardcoded check in `main.dart` for this.
 Ensure you have [melos](https://melos.invertase.dev/~melos-latest/getting-started) installed.
 
 1. `cd demos/local-only-todolist`
 2. `melos prepare`
-3. `cp lib/app_config_template.dart lib/app_config.dart`
-4. Insert your Supabase and PowerSync project credentials into `lib/app_config.dart` (See instructions below)
-5. `flutter run`
+3. `flutter run`
+
+# Setting up sync functionality
+
+Insert your Supabase and PowerSync project credentials into `lib/app_config.dart` (See instructions below).
+A user should now be able to login or sign up, which enables the sync functionality.
 
 # Set up Supabase Project
 

demos/local-only-todolist/lib/app_config_template.dart renamed to demos/local-only-todolist/lib/app_config.dart

@@ -1,5 +1,4 @@
-// Copy this template: `cp lib/app_config_template.dart lib/app_config.dart`
-// Edit lib/app_config.dart and enter your Supabase and PowerSync project details.
+// Enter your Supabase and PowerSync project details.
 class AppConfig {
   static const String supabaseUrl = 'https://foo.supabase.co';
   static const String supabaseAnonKey = 'foo';

demos/local-only-todolist/lib/main.dart

@@ -1,6 +1,7 @@
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:logging/logging.dart';
+import 'package:powersync_flutter_local_only_demo/app_config.dart';
 import 'package:powersync_flutter_local_only_demo/models/schema.dart';
 import 'package:powersync_flutter_local_only_demo/models/sync_mode.dart';
 
@@ -126,6 +127,10 @@ class MyHomePage extends StatelessWidget {
                   ));
                 }
               },
+              enabled: // disable login/signup if credentials aren't configured.
+                  !(AppConfig.supabaseUrl == "https://foo.supabase.co" ||
+                      AppConfig.powersyncUrl ==
+                          "https://foo.powersync.journeyapps.com"),
             ),
           ],
         ),

demos/local-only-todolist/lib/models/schema.dart

@@ -1,21 +1,32 @@
 import 'package:powersync/powersync.dart';
 import 'package:powersync_flutter_local_only_demo/models/sync_mode.dart';
 
-/// The schema contains two copies of each table - a local-only one, and
-/// a online/synced one. Depending on the 'online' flag, one of those gets
-/// the main 'lists' / 'todos' view name.
+/// This schema design supports an online/local-only workflow by managing data
+/// across two versions of each table: one for local/offline use and one for
+/// online/synced use. This approach simplifies the handling of data in different
+/// connectivity states.
 ///
 /// For local only, the views become:
 ///   online_todos
 ///   todos
 ///   online_lists
 ///   lists
+///
+/// - 'todos' and 'lists' refer to the local-only data.
+/// - 'online_todos' and 'online_lists' refer to the data that will be synced
+///    once online, making it clear that these are not currently synchronized.
+///
 /// For online, we have these views:
 ///   todos
 ///   local_todos
 ///   lists
 ///   local_lists
 ///
+/// - 'todos' and 'lists' refer to the synced/online data.
+/// - local_todos' and 'local_lists' refer to the local-only data, allowing
+///   for temporary storage or operations before syncing.
+///
+///  For an offline-to-online transition [switchToOnlineSchema] copies data so that it ends up in the upload queue.
 
 const todosTable = 'todos';
 const listsTable = 'lists';
@@ -69,7 +80,7 @@ Schema makeSchema({online = bool}) {
 
 switchToOnlineSchema(PowerSyncDatabase db, String userId) async {
   await db.updateSchema(makeSchema(online: true));
-  await setSyncMode(true);
+  await setSyncEnabled(true);
 
   await db.writeTransaction((tx) async {
     // Copy local data to the "online" views.

demos/local-only-todolist/lib/models/sync_mode.dart

@@ -28,19 +28,19 @@ openSyncModeDatabase() async {
   await migrations.migrate(sqliteDb);
 }
 
-Future<bool> getSyncMode() async {
+Future<bool> getSyncEnabled() async {
   var rows = await sqliteDb
       .getAll('SELECT sync_enabled from local_system where id = 1');
 
   if (rows.isEmpty) {
-    await setSyncMode(false);
+    await setSyncEnabled(false);
     return false;
   }
 
   return rows[0]['sync_enabled'] == 'TRUE';
 }
 
-setSyncMode(bool enabled) async {
+setSyncEnabled(bool enabled) async {
   var enabledString = enabled ? "TRUE" : "FALSE";
   await sqliteDb.execute(
       'INSERT OR REPLACE INTO local_system(id, sync_enabled) VALUES (1, ?);',

demos/local-only-todolist/lib/powersync.dart

@@ -157,7 +157,7 @@ Future<String> getDatabasePath() async {
 }
 
 Future<void> openDatabase() async {
-  var isSyncMode = await getSyncMode();
+  var isSyncMode = await getSyncEnabled();
   db = PowerSyncDatabase(
       schema: makeSchema(online: isSyncMode),
       path: await getDatabasePath(),
@@ -177,7 +177,7 @@ Future<void> connectDatabase() async {
     log.severe("Can't connect database without being signed in");
   }
   SupabaseConnector? currentConnector;
-  var isSyncMode = await getSyncMode();
+  var isSyncMode = await getSyncEnabled();
 
   if (!isSyncMode) {
     await switchToOnlineSchema(db, getUserId());
@@ -206,6 +206,6 @@ Future<void> logout() async {
   await db.disconnectAndClear();
 
   // Resetting app so that no-sync mode works again
-  await await setSyncMode(false);
+  await await setSyncEnabled(false);
   await openDatabase();
 }