83774f5f61
- CdnUrlResolver: 相对路径/S3 URL 统一解析为 apiBaseUrl 代理链路 (#14) - FileDownloadManager: Notifier<Map<url, state>>，四态（idle/progress/done/failed）， 断点续传 + 取消令牌 + 本地缓存（systemTemp/im_file_cache） (#15) - FileMessageBubble: 三态 UI，文件类型图标/颜色，大小格式化， idle/failed 点击触发下载，done 点击回调 open_filex TODO (#16) - AudioMessageBubble: 语音消息下载框架，静态波形装饰， 播放 TODO（audioplayers 接入后解开） (#17) - VideoMessageBubble: 缩略图 Image.network + CdnUrlResolver， 播放按钮覆盖，上传进度环，video_player 接入 TODO (#18) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
164 lines
4.6 KiB
Markdown
164 lines
4.6 KiB
Markdown
# 文件下载 — 架构文档
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> 对应 Gitea issues #14–#18
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> 参考实现：`im-client-ios-swift-demo` FileDownloadManager + AudioPlaybackService + ChatMessageBubble
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---
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## 1. 功能范围
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| Issue | 功能 | 状态 |
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|-------|------|------|
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| #14 | CDN URL 解析器（CdnUrlResolver） | ✅ 已实现 |
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| #15 | FileDownloadManager — 下载服务 + 缓存 | ✅ 已实现 |
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| #16 | FileMessageBubble — 文件气泡三态 UI | ✅ 已实现 |
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| #17 | AudioMessageBubble — 语音下载框架 | ✅ 框架（播放需 audioplayers） |
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| #18 | VideoMessageBubble — 视频缩略图框架 | ✅ 框架（播放需 video_player） |
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---
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## 2. 目录结构
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```
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core/services/
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├── cdn_url_resolver.dart # CDN 路径 → 完整 URL
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└── file_download_manager.dart # 下载服务（进度追踪 + 缓存）
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features/chat/view/widgets/
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├── file_message_bubble.dart # 文件消息气泡（三态 UI）
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├── audio_message_bubble.dart # 语音消息气泡（下载框架）
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└── video_message_bubble.dart # 视频消息气泡（缩略图框架）
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```
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---
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## 3. 核心概念
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### 3.1 FileDownloadState
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```
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idle → 未下载（显示下载图标）
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downloading(progress: 0.0~1.0) → 下载中（进度条）
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downloaded(localPath: String) → 已缓存（显示打开图标）
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failed(error: String) → 失败（显示重试图标）
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```
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### 3.2 CDN URL 路由策略
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```
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相对路径 Files/xxx.pdf → apiBaseUrl/Files/xxx.pdf
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完整 HTTP http://xxx.com/f → 直接使用
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S3 URL *.amazonaws.com → apiBaseUrl + S3 path（通过 API 代理）
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```
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S3 桶是私有的，直接访问返回 403。所有下载都必须经过 `apiBaseUrl` 代理。
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### 3.3 缓存策略
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```
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缓存目录：Directory.systemTemp/im_file_cache/
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文件名： {url.hashCode 8位 hex}_{sanitized_filename}
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命中条件：文件存在 && 大小 > 0
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清理策略：由 OS 自动清理 temp 目录（同 iOS Library/Caches 语义）
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```
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---
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## 4. 数据流
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### 4.1 文件消息下载
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```
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FileMessageBubble.onTap
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└─ fileDownloadManagerProvider.notifier.download(url, fileName)
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├─ CdnUrlResolver.resolve(url) → 完整下载 URL
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├─ _cacheKeyFor(url, fileName) → 本地文件名
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├─ File(cachePath).exists() ?
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│ true → state = downloaded(cachePath)
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│ false → NetworksSdkApi.executeDownload(url, savePath, onProgress)
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│ → state = downloading(progress)
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│ → state = downloaded(cachePath) / failed(error)
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└─ 返回 localPath（供 open_filex 打开）
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```
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### 4.2 语音消息
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```
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AudioMessageBubble
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└─ 点击播放按钮
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└─ FileDownloadManager.download(voiceUrl, 'voice_{cmid}.m4a')
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→ downloaded(localPath)
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→ TODO: AudioPlayer().play(DeviceFileSource(localPath))
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```
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### 4.3 视频消息
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```
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VideoMessageBubble
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└─ 显示：Image.network(CdnUrlResolver.resolve(thumbUrl)) // 缩略图
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└─ 点击播放按钮
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→ TODO: Navigator 推送全屏视频页（video_player 流式播放）
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```
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---
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## 5. Provider 设计
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```
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fileDownloadManagerProvider
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NotifierProvider<FileDownloadManager, Map<String, FileDownloadState>>
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└─ NetworksSdkApi (via networkSdkApiProvider)
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```
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与 Settings ViewModel 一致，使用手动 `Notifier<T>` + `NotifierProvider`，
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不依赖 `@riverpod` 代码生成。
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---
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## 6. 消息类型路由（rawContent 解析）
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| typ | 类型 | rawContent 格式 |
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|-----|------|----------------|
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| 3 | 语音 | `{"url":"...","duration":N}` |
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| 4 | 视频 | `{"url":"...","thumb":"...","size":N}` |
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| 6 | 文件 | `{"url":"...","name":"...","size":N}` |
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| 24 | 视频（秘密） | 同 typ=4 |
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---
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## 7. 待完成
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- **audioplayers 接入**：`AudioMessageBubble` 中 TODO 解开，安装 `audioplayers: ^6.0.0`
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- **video_player 接入**：`VideoMessageBubble` 点击推送全屏路由，安装 `video_player: ^2.9.0`
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- **open_filex 接入**：`FileMessageBubble` downloaded 态打开文件，安装 `open_filex: ^3.0.3`
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- **XOR 解密**：`secret/` 路径文件解密（cipher_guard_sdk 接入时实现）
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### 接入 open_filex 步骤
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```yaml
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# apps/im_app/pubspec.yaml
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dependencies:
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open_filex: ^3.0.3
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```
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```dart
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// FileMessageBubble downloaded 态 onTap：
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import 'package:open_filex/open_filex.dart';
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await OpenFilex.open(localPath);
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```
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### 接入 audioplayers 步骤
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```yaml
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# apps/im_app/pubspec.yaml
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dependencies:
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audioplayers: ^6.0.0
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```
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```dart
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// AudioMessageBubble 播放：
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import 'package:audioplayers/audioplayers.dart';
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final player = AudioPlayer();
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await player.play(DeviceFileSource(localPath));
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```
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