Flutter分布式数据存储插件at_client的使用

简介

at_client 是一个用于构建基于 atProtocol 的应用程序的非平台特定客户端 SDK。它提供了基本的方法来实现去中心化、边缘计算模型，具有以下特性：

• 通过个人数据存储进行加密控制数据访问
• 不需要应用后端
• 端到端加密，只有数据所有者拥有密钥
• 私有且无监视的连接

我们称之为“翻转互联网”，即给人们控制其数据访问的权利。

开始使用

在第一次使用此包之前，您应该遵循 getting started guide。您可能还需要阅读 atPlatform 概述。

该包可在 pub.dev 上找到：https://pub.dev/packages/at_client

使用示例

设置 AtClientPreferences

首先，设置您的偏好设置：

import 'package:path_provider/path_provider.dart';
import 'package:at_client/at_client.dart';

Future<void> setupPreferences() async {
  Directory appSupportDir = await getApplicationSupportDirectory();
  AtClientPreference preferences = AtClientPreference()
    ..rootDomain = 'root.atsign.org'
    ..namespace = '.my_namespace'
    ..hiveStoragePath = appSupportDir.path
    ..commitLogPath = appSupportDir.path
    ..isLocalStoreRequired = true;

  // 初始化当前用户
  AtClientManager atClientManagerInstance = await AtClientManager.getInstance().setCurrentAtSign('@yourAtsign', 'appNamespace', preferences);
}

更新用户数据

使用 put() 方法更新数据：

Future<void> updateData(AtClient atClientInstance) async {
  AtKey atKey = AtKey()
    ..key = 'phone'
    ..namespace = '.myApp';
  
  await atClientInstance.put(atKey, '+00 123-456-7890');
}

获取数据

使用 get() 方法获取数据：

Future<void> getData(AtClient atClientInstance) async {
  AtKey atKey = AtKey()
    ..key = 'phone'
    ..namespace = '.myApp';
  
  AtValue value = await atClientInstance.get(atKey);
  print(value.value); // 输出: +00 123-456-7890
}

删除数据

使用 delete() 方法删除数据：

Future<void> deleteData(AtClient atClientInstance) async {
  AtKey atKey = AtKey()
    ..key = 'phone'
    ..namespace = '.myApp';
  
  bool isDeleted = await atClientInstance.delete(atKey);
  print(isDeleted); // 如果删除成功，输出: true
}

同步数据

如果需要，可以使用 sync() 方法同步数据：

SyncService _syncService;

void syncData(AtClientManager atClientManagerInstance) {
  _syncService = atClientManagerInstance.syncService;
  _syncService.sync();
}

发送通知

使用 notify() 方法发送通知：

Future<void> notifyUpdate(AtClient atClientInstance) async {
  MetaData metaData = MetaData()
    ..ttl = '60000'
    ..ttb = '30000';

  AtKey key = AtKey()
    ..key = 'phone'
    ..sharedWith = '@bob'
    ..metadata = metaData
    ..namespace = '.myApp';

  String value = (await atClientInstance.get(key)).value;
  OperationEnum operation = OperationEnum.update;

  bool isNotified = await atClientInstance.notify(key, value, operation);
  print(isNotified); // 如果通知成功，输出: true
}

监听连接状态

使用 ConnectivityListener 监听连接状态：

void checkConnection() {
  ConnectivityListener().subscribe().listen((isConnected) {
    if (isConnected) {
      print('connection available');
    } else {
      print('connection lost');
    }
  });
}

完整示例

以下是一个完整的示例，展示如何使用 at_client 插件：

import 'package:at_client/at_client.dart';
import 'package:at_client/src/util/encryption_util.dart';
import 'package:path_provider/path_provider.dart';
import 'package:flutter/material.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();

  Directory appSupportDir = await getApplicationSupportDirectory();
  AtClientPreference preferences = AtClientPreference()
    ..rootDomain = 'root.atsign.org'
    ..namespace = '.myApp'
    ..hiveStoragePath = appSupportDir.path
    ..commitLogPath = appSupportDir.path
    ..isLocalStoreRequired = true;

  AtClientManager atClientManagerInstance = await AtClientManager.getInstance().setCurrentAtSign('@yourAtsign', 'myApp', preferences);

  runApp(MyApp(atClientManagerInstance));
}

class MyApp extends StatelessWidget {
  final AtClientManager atClientManagerInstance;

  MyApp(this.atClientManagerInstance);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: Text('at_client Example')),
        body: Center(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: <Widget>[
              ElevatedButton(
                onPressed: () async {
                  AtKey atKey = AtKey()
                    ..key = 'phone'
                    ..namespace = '.myApp';
                  
                  await atClientManagerInstance.atClient.put(atKey, '+00 123-456-7890');
                  print('Data updated');
                },
                child: Text('Update Data'),
              ),
              ElevatedButton(
                onPressed: () async {
                  AtKey atKey = AtKey()
                    ..key = 'phone'
                    ..namespace = '.myApp';
                  
                  AtValue value = await atClientManagerInstance.atClient.get(atKey);
                  print('Phone number: ${value.value}');
                },
                child: Text('Get Data'),
              ),
            ],
          ),
        ),
      ),
    );
  }
}

请参考 at_sign docs 获取更多详细信息。