64 lines
1.7 KiB
Dart
64 lines
1.7 KiB
Dart
import 'dart:convert';
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import 'dart:io';
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import 'dart:typed_data';
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import 'package:crypto/crypto.dart';
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import 'package:path_provider/path_provider.dart';
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import 'package:video_thumbnail/video_thumbnail.dart';
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/// 视频封面缓存：优先从本地读取，未命中则生成并缓存
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class VideoThumbnailCache {
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VideoThumbnailCache._();
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static final VideoThumbnailCache _instance = VideoThumbnailCache._();
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static VideoThumbnailCache get instance => _instance;
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static const int _maxWidth = 400;
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static const int _quality = 75;
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Future<Uint8List?> getThumbnail(String videoUrl) async {
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final key = _cacheKey(videoUrl);
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final cacheDir = await _getCacheDir();
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final file = File('${cacheDir.path}/$key.jpg');
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if (await file.exists()) {
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return file.readAsBytes();
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}
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try {
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final path = await VideoThumbnail.thumbnailFile(
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video: videoUrl,
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thumbnailPath: cacheDir.path,
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imageFormat: ImageFormat.JPEG,
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maxWidth: _maxWidth,
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quality: _quality,
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);
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if (path != null) {
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final cached = File(path);
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final bytes = await cached.readAsBytes();
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if (cached.path != file.path) {
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await file.writeAsBytes(bytes);
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cached.deleteSync();
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}
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return bytes;
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}
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} catch (_) {}
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return null;
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}
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String _cacheKey(String url) {
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final bytes = utf8.encode(url);
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final digest = md5.convert(bytes);
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return digest.toString();
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}
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Directory? _cacheDir;
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Future<Directory> _getCacheDir() async {
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_cacheDir ??= await getTemporaryDirectory();
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final dir = Directory('${_cacheDir!.path}/video_thumbnails');
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if (!await dir.exists()) {
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await dir.create(recursive: true);
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}
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return dir;
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}
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}
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