Flutter

import 'package:powersync/powersync.dart';

const schema = Schema(([
  Table('todos', [
    Column.text('list_id'),
    Column.text('created_at'),
    Column.text('completed_at'),
    Column.text('description'),
    Column.integer('completed'),
    Column.text('created_by'),
    Column.text('completed_by'),
  ], indexes: [
    // Index to allow efficient lookup within a list
    Index('list', [IndexedColumn('list_id')])
  ]),
  Table('lists', [
    Column.text('created_at'),
    Column.text('name'),
    Column.text('owner_id')
  ])
]));

import 'package:path/path.dart';
import 'package:path_provider/path_provider.dart';
import 'package:powersync/powersync.dart';
import '../main.dart';
import '../models/schema.dart';

openDatabase() async {
  final dir = await getApplicationSupportDirectory();
  final path = join(dir.path, 'powersync-dart.db');

  // Set up the database
  // Inject the Schema you defined in the previous step and a file path
  db = PowerSyncDatabase(schema: schema, path: path);
  await db.initialize();
}

import 'package:powersync/powersync.dart';

class MyBackendConnector extends PowerSyncBackendConnector {
  PowerSyncDatabase db;

  MyBackendConnector(this.db);
  @override
  Future<PowerSyncCredentials?> fetchCredentials() async {
    // Implement fetchCredentials to obtain a JWT from your authentication service
    // If you're using Supabase or Firebase, you can re-use the JWT from those clients, see
    // - https://docs.powersync.com/installation/authentication-setup/supabase-auth
    // - https://docs.powersync.com/installation/authentication-setup/firebase-auth

    // See example implementation here: https://pub.dev/documentation/powersync/latest/powersync/DevConnector/fetchCredentials.html

    return PowerSyncCredentials(
      endpoint: 'https://xxxxxx.powersync.journeyapps.com',
      // Use a development token (see Authentication Setup https://docs.powersync.com/installation/authentication-setup/development-tokens) to get up and running quickly
      token: 'An authentication token'
    );
  }

  // Implement uploadData to send local changes to your backend service
  // You can omit this method if you only want to sync data from the server to the client
  // See example implementation here: https://docs.powersync.com/client-sdk-references/flutter#3-integrate-with-your-backend
  @override
  Future<void> uploadData(PowerSyncDatabase database) async {
    // This function is called whenever there is data to upload, whether the
    // device is online or offline.
    // If this call throws an error, it is retried periodically.

    final transaction = await database.getNextCrudTransaction();
    if (transaction == null) {
      return;
    }

    // The data that needs to be changed in the remote db
    for (var op in transaction.crud) {
      switch (op.op) {
        case UpdateType.put:
          // TODO: Instruct your backend API to CREATE a record
        case UpdateType.patch:
          // TODO: Instruct your backend API to PATCH a record
        case UpdateType.delete:
        //TODO: Instruct your backend API to DELETE a record
      }
    }

    // Completes the transaction and moves onto the next one
    await transaction.complete();
  }
}

/// This is a simple model class representing a TodoList
class TodoList {
  final int id;
  final String name;
  final DateTime createdAt;
  final DateTime updatedAt;

  TodoList({
    required this.id,
    required this.name,
    required this.createdAt,
    required this.updatedAt,
  });

  factory TodoList.fromRow(Map<String, dynamic> row) {
    return TodoList(
      id: row['id'],
      name: row['name'],
      createdAt: DateTime.parse(row['created_at']),
      updatedAt: DateTime.parse(row['updated_at']),
    );
  }
}

import '../main.dart';
import '../models/todolist.dart';

Future<TodoList> find(id) async {
  final result = await db.get('SELECT * FROM lists WHERE id = ?', [id]);
  return TodoList.fromRow(result);
}

import 'package:powersync/sqlite3.dart';
import '../main.dart';

Future<List<String>> getLists() async {
  ResultSet results = await db.getAll('SELECT id FROM lists WHERE id IS NOT NULL');
  List<String> ids = results.map((row) => row['id'] as String).toList();
  return ids;
}