559 lines
15 KiB
TypeScript
559 lines
15 KiB
TypeScript
/**
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* M3U8 下载器核心逻辑
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* 基于 M3U8Download 项目改造为 TypeScript 版本
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*/
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import { AESDecryptor } from './aes-decryptor';
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// @ts-ignore - mux.js 没有类型定义
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import * as muxjs from 'mux.js';
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export interface M3U8DownloadTask {
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id: string;
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url: string;
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title: string;
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type: 'TS' | 'MP4';
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status: 'ready' | 'downloading' | 'pause' | 'done' | 'error';
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finishList: Array<{ title: string; status: '' | 'is-downloading' | 'is-success' | 'is-error' }>;
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tsUrlList: string[];
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requests: XMLHttpRequest[];
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mediaFileList: ArrayBuffer[];
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downloadIndex: number;
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downloading: boolean;
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durationSecond: number;
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beginTime: Date;
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errorNum: number;
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finishNum: number;
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retryNum: number;
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retryCountdown: number;
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rangeDownload: {
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isShowRange: boolean;
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startSegment: number;
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endSegment: number;
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targetSegment: number;
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};
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aesConf: {
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method: string;
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uri: string;
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iv: Uint8Array | null;
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key: ArrayBuffer | null;
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decryption: AESDecryptor | null;
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};
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}
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export interface M3U8DownloaderOptions {
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onProgress?: (task: M3U8DownloadTask) => void;
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onComplete?: (task: M3U8DownloadTask) => void;
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onError?: (task: M3U8DownloadTask, error: string) => void;
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}
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export class M3U8Downloader {
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private tasks: Map<string, M3U8DownloadTask> = new Map();
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private currentTask: M3U8DownloadTask | null = null;
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private options: M3U8DownloaderOptions;
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constructor(options: M3U8DownloaderOptions = {}) {
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this.options = options;
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}
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/**
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* 创建下载任务
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*/
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async createTask(url: string, title: string, type: 'TS' | 'MP4' = 'TS'): Promise<string> {
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const taskId = 't_' + Date.now() + Math.random().toString(36).substr(2, 9);
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try {
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// 获取 m3u8 文件内容
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const m3u8Content = await this.fetchM3U8(url);
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if (!m3u8Content.startsWith('#EXTM3U')) {
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throw new Error('无效的 m3u8 链接');
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}
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// 检查是否是主播放列表
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if (this.isMasterPlaylist(m3u8Content)) {
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const streams = this.parseStreamInfo(m3u8Content, url);
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if (streams.length > 0) {
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// 自动选择最高清晰度
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url = streams[0].url;
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const subM3u8Content = await this.fetchM3U8(url);
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return this.processM3U8Content(taskId, url, title, type, subM3u8Content);
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}
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}
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return this.processM3U8Content(taskId, url, title, type, m3u8Content);
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} catch (error) {
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throw new Error(`创建任务失败: ${error}`);
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}
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}
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/**
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* 处理 M3U8 内容
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*/
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private processM3U8Content(
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taskId: string,
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url: string,
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title: string,
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type: 'TS' | 'MP4',
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m3u8Content: string
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): string {
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const task: M3U8DownloadTask = {
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id: taskId,
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url,
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title,
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type,
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status: 'ready',
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finishList: [],
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tsUrlList: [],
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requests: [],
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mediaFileList: [],
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downloadIndex: 0,
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downloading: false,
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durationSecond: 0,
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beginTime: new Date(),
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errorNum: 0,
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finishNum: 0,
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retryNum: 3,
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retryCountdown: 0,
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rangeDownload: {
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isShowRange: false,
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startSegment: 1,
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endSegment: 0,
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targetSegment: 0,
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},
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aesConf: {
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method: '',
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uri: '',
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iv: null,
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key: null,
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decryption: null,
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},
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};
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// 解析 TS 片段
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const lines = m3u8Content.split('\n');
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for (let i = 0; i < lines.length; i++) {
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const line = lines[i].trim();
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if (line.startsWith('#EXTINF:')) {
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const duration = parseFloat(line.split('#EXTINF:')[1]);
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task.durationSecond += duration;
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} else if (line.startsWith('#EXT-X-KEY')) {
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const keyMatch = line.match(/METHOD=([^,]+)(?:,URI="([^"]+)")?(?:,IV=([^,]+))?/);
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if (keyMatch) {
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task.aesConf.method = keyMatch[1];
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task.aesConf.uri = keyMatch[2] ? this.applyURL(keyMatch[2], url) : '';
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task.aesConf.iv = keyMatch[3] ? this.parseIV(keyMatch[3]) : null;
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}
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} else if (line && !line.startsWith('#')) {
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task.tsUrlList.push(this.applyURL(line, url));
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task.finishList.push({ title: line, status: '' });
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}
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}
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task.rangeDownload.endSegment = task.tsUrlList.length;
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task.rangeDownload.targetSegment = task.tsUrlList.length;
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this.tasks.set(taskId, task);
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return taskId;
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}
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/**
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* 开始下载任务
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*/
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async startTask(taskId: string): Promise<void> {
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const task = this.tasks.get(taskId);
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if (!task) {
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throw new Error('任务不存在');
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}
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if (task.status === 'downloading') {
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return;
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}
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// 如果需要 AES 解密，先获取密钥
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if (task.aesConf.method && task.aesConf.method !== 'NONE' && !task.aesConf.key) {
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await this.getAESKey(task);
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}
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task.status = 'downloading';
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this.currentTask = task;
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this.downloadTS(task);
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}
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/**
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* 暂停任务
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*/
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pauseTask(taskId: string): void {
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const task = this.tasks.get(taskId);
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if (!task) return;
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task.status = 'pause';
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this.abortRequests(task);
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}
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/**
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* 取消任务
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*/
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cancelTask(taskId: string): void {
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const task = this.tasks.get(taskId);
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if (!task) return;
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this.abortRequests(task);
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this.tasks.delete(taskId);
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if (this.currentTask?.id === taskId) {
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this.currentTask = null;
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}
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}
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/**
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* 获取任务信息
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*/
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getTask(taskId: string): M3U8DownloadTask | undefined {
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return this.tasks.get(taskId);
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}
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/**
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* 获取所有任务
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*/
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getAllTasks(): M3U8DownloadTask[] {
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return Array.from(this.tasks.values());
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}
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/**
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* 获取下载进度
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*/
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getProgress(taskId: string): number {
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const task = this.tasks.get(taskId);
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if (!task) return 0;
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if (task.rangeDownload.targetSegment === 0) return 0;
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return (task.finishNum / task.rangeDownload.targetSegment) * 100;
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}
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/**
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* 下载 TS 片段
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*/
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private downloadTS(task: M3U8DownloadTask): void {
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const download = () => {
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const isPause = task.status === 'pause';
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const index = task.downloadIndex;
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if (index >= task.rangeDownload.endSegment || isPause) {
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return;
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}
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task.downloadIndex++;
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if (task.finishList[index] && task.finishList[index].status === '') {
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task.finishList[index].status = 'is-downloading';
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const xhr = new XMLHttpRequest();
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xhr.responseType = 'arraybuffer';
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xhr.onreadystatechange = () => {
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if (xhr.readyState === 4) {
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if (xhr.status >= 200 && xhr.status < 300) {
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this.dealTS(task, xhr.response, index, () => {
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if (task.downloadIndex < task.rangeDownload.endSegment && !isPause) {
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download();
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}
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});
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} else {
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task.errorNum++;
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task.finishList[index].status = 'is-error';
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this.options.onError?.(task, `片段 ${index} 下载失败`);
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if (task.downloadIndex < task.rangeDownload.endSegment) {
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!isPause && download();
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}
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}
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}
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};
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xhr.open('GET', task.tsUrlList[index], true);
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xhr.send();
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task.requests.push(xhr);
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} else if (task.downloadIndex < task.rangeDownload.endSegment) {
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!isPause && download();
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}
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};
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// 并发下载 6 个片段
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const concurrency = Math.min(6, task.rangeDownload.targetSegment - task.finishNum);
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for (let i = 0; i < concurrency; i++) {
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download();
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}
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}
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/**
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* 处理 TS 片段
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*/
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private dealTS(
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task: M3U8DownloadTask,
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file: ArrayBuffer,
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index: number,
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callback: () => void
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): void {
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let data = file;
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// AES 解密
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if (task.aesConf.key) {
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data = this.aesDecrypt(task, data, index);
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}
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// MP4 转码（如果需要）
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if (task.type === 'MP4') {
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this.conversionMp4(task, data, index, (convertedData) => {
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task.mediaFileList[index - task.rangeDownload.startSegment + 1] = convertedData;
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task.finishList[index].status = 'is-success';
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task.finishNum++;
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this.options.onProgress?.(task);
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if (task.finishNum === task.rangeDownload.targetSegment) {
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task.status = 'done';
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this.downloadFile(task);
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this.options.onComplete?.(task);
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}
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callback();
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});
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} else {
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task.mediaFileList[index - task.rangeDownload.startSegment + 1] = data;
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task.finishList[index].status = 'is-success';
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task.finishNum++;
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this.options.onProgress?.(task);
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if (task.finishNum === task.rangeDownload.targetSegment) {
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task.status = 'done';
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this.downloadFile(task);
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this.options.onComplete?.(task);
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}
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callback();
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}
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}
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/**
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* 下载文件
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*/
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private downloadFile(task: M3U8DownloadTask): void {
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const fileBlob = new Blob(task.mediaFileList, {
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type: task.type === 'MP4' ? 'video/mp4' : 'video/MP2T',
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});
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const a = document.createElement('a');
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a.href = URL.createObjectURL(fileBlob);
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a.download = `${task.title}.${task.type === 'MP4' ? 'mp4' : 'ts'}`;
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a.style.display = 'none';
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document.body.appendChild(a);
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a.click();
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document.body.removeChild(a);
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URL.revokeObjectURL(a.href);
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}
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/**
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* 获取 M3U8 文件
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*/
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private async fetchM3U8(url: string): Promise<string> {
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return new Promise((resolve, reject) => {
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const xhr = new XMLHttpRequest();
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xhr.onreadystatechange = () => {
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if (xhr.readyState === 4) {
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if (xhr.status >= 200 && xhr.status < 300) {
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resolve(xhr.responseText);
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} else {
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reject(new Error(`HTTP ${xhr.status}`));
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}
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}
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};
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xhr.open('GET', url, true);
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xhr.send();
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});
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}
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/**
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* 检测是否是主播放列表
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*/
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private isMasterPlaylist(m3u8Str: string): boolean {
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return m3u8Str.includes('#EXT-X-STREAM-INF');
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}
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/**
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* 解析流信息
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*/
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private parseStreamInfo(m3u8Str: string, baseUrl: string): Array<{
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url: string;
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bandwidth: number;
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resolution: string;
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name: string;
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}> {
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const streams: Array<{
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url: string;
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bandwidth: number;
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resolution: string;
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name: string;
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}> = [];
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const lines = m3u8Str.split('\n');
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for (let i = 0; i < lines.length; i++) {
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const line = lines[i].trim();
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if (line.startsWith('#EXT-X-STREAM-INF:')) {
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const bandwidth = line.match(/BANDWIDTH=(\d+)/)?.[1] || '';
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const resolution = line.match(/RESOLUTION=([^\s,]+)/)?.[1] || '';
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const name = line.match(/NAME="([^"]+)"/)?.[1] || '';
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if (i + 1 < lines.length) {
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const url = lines[i + 1].trim();
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if (url && !url.startsWith('#')) {
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streams.push({
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url: this.applyURL(url, baseUrl),
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bandwidth: parseInt(bandwidth) || 0,
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resolution: resolution || 'Unknown',
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name: name || `${resolution || ''} ${bandwidth ? parseInt(bandwidth) / 1000 + 'kbps' : 'Unknown'}`,
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});
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i++;
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}
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}
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}
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}
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streams.sort((a, b) => b.bandwidth - a.bandwidth);
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return streams;
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}
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/**
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* 合成 URL
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*/
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private applyURL(targetURL: string, baseURL: string): string {
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if (targetURL.indexOf('http') === 0) {
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return targetURL;
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} else if (targetURL[0] === '/') {
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const domain = baseURL.split('/');
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return domain[0] + '//' + domain[2] + targetURL;
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} else {
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const domain = baseURL.split('/');
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domain.pop();
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return domain.join('/') + '/' + targetURL;
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}
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}
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/**
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* 解析 IV
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*/
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private parseIV(ivString: string): Uint8Array {
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const hex = ivString.replace(/^0x/, '');
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return new Uint8Array(hex.match(/.{1,2}/g)!.map((byte) => parseInt(byte, 16)));
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}
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/**
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* 获取 AES 密钥
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*/
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private async getAESKey(task: M3U8DownloadTask): Promise<void> {
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return new Promise((resolve, reject) => {
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const xhr = new XMLHttpRequest();
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xhr.responseType = 'arraybuffer';
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xhr.onreadystatechange = () => {
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if (xhr.readyState === 4) {
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if (xhr.status >= 200 && xhr.status < 300) {
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task.aesConf.key = xhr.response;
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// 初始化 AES 解密器
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task.aesConf.decryption = new AESDecryptor();
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task.aesConf.decryption.expandKey(task.aesConf.key);
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resolve();
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} else {
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reject(new Error('获取 AES 密钥失败'));
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}
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}
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};
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xhr.open('GET', task.aesConf.uri, true);
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xhr.send();
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});
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}
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/**
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* AES 解密
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*/
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private aesDecrypt(task: M3U8DownloadTask, data: ArrayBuffer, index: number): ArrayBuffer {
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if (!task.aesConf.decryption) {
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return data;
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}
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// 使用 IV 或默认 IV
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let iv: Uint8Array;
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if (task.aesConf.iv) {
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iv = task.aesConf.iv;
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} else {
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// 如果没有指定 IV，使用片段索引作为 IV
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iv = new Uint8Array(16);
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for (let i = 12; i < 16; i++) {
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iv[i] = (index >> (8 * (15 - i))) & 0xff;
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}
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}
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try {
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return task.aesConf.decryption.decrypt(data, 0, iv.buffer, true);
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} catch (error) {
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console.error('AES 解密失败:', error);
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return data;
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}
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}
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/**
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* MP4 转码
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*/
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private conversionMp4(
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task: M3U8DownloadTask,
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data: ArrayBuffer,
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index: number,
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callback: (data: ArrayBuffer) => void
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): void {
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if (task.type === 'MP4') {
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try {
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// @ts-ignore - mux.js 的 Transmuxer 在 mp4 子模块下
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const transMuxer = new muxjs.mp4.Transmuxer({
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keepOriginalTimestamps: true,
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duration: parseInt(task.durationSecond.toString()),
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});
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transMuxer.on('data', (segment: any) => {
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// 第一个片段需要包含初始化段
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if (index === task.rangeDownload.startSegment - 1) {
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const combinedData = new Uint8Array(
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segment.initSegment.byteLength + segment.data.byteLength
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);
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combinedData.set(segment.initSegment, 0);
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combinedData.set(segment.data, segment.initSegment.byteLength);
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callback(combinedData.buffer);
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} else {
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callback(segment.data);
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}
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});
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transMuxer.push(new Uint8Array(data));
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transMuxer.flush();
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} catch (error) {
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console.error('MP4 转码失败:', error);
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// 转码失败，返回原始数据
|
|
callback(data);
|
|
}
|
|
} else {
|
|
// TS 格式直接返回
|
|
callback(data);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 终止请求
|
|
*/
|
|
private abortRequests(task: M3U8DownloadTask): void {
|
|
task.requests.forEach((xhr) => {
|
|
if (xhr.readyState !== 4) {
|
|
xhr.abort();
|
|
}
|
|
});
|
|
task.requests = [];
|
|
}
|
|
}
|