574 lines
25 KiB
C#
574 lines
25 KiB
C#
using System.Diagnostics;
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using System.Net.Http;
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using System.Text;
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using System.Text.RegularExpressions;
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namespace WinFormsApp3
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{
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/// <summary>
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/// 下载进度：文字说明 + 可选的百分比（0~1）。
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/// </summary>
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public record DownloadProgress(string Message, double? Ratio);
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/// <summary>
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/// 下载结果。
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/// </summary>
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/// <param name="FilePath">最终落盘的文件路径（HLS 转封装后可能改变扩展名）。</param>
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/// <param name="Bytes">写出的字节数。</param>
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/// <param name="Converted">是否由 ffmpeg 把 ts 转封装为 mp4。</param>
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public record DownloadResult(string FilePath, long Bytes, bool Converted);
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/// <summary>
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/// 视频下载器：支持直链（mp4/flv/ts…）与 HLS（m3u8）分片合并下载。
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/// 请求时带上当前页面 Referer，抖音等站点校验 Referer 后才允许访问播放地址。
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/// </summary>
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public class VideoDownloader
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{
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private const string UserAgent =
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"Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0.0.0 Safari/537.36 Edg/126.0.0.0";
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private static readonly Regex CharsetRx = new(@"charset\s*=\s*""?([\w-]+)""?", RegexOptions.IgnoreCase);
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private static readonly string[] MediaExtensions =
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[".mp4", ".flv", ".m3u8", ".mpd", ".mkv", ".mov", ".m4v", ".webm", ".f4v", ".3gp", ".ts", ".mpg", ".mpeg"];
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/// <summary>
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/// 整片容器格式。这些后缀永远不能当作 HLS 分片，否则 /video/xxx.flv 这类地址会被误删。
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/// </summary>
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private static readonly string[] WholeVideoExtensions =
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[".mp4", ".flv", ".mkv", ".mov", ".webm", ".m4v", ".f4v", ".3gp", ".avi", ".rmvb", ".mpg", ".mpeg", ".m3u8", ".mpd"];
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private readonly string? _referer;
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private readonly string? _cookie;
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/// <param name="referer">播放器所在页面的地址，不是顶层页面地址（播放器常在跨域 iframe 里）。</param>
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/// <param name="cookie">从 WebView2 配置文件里取出的 Cookie，部分站点没 Cookie 直接给空文件。</param>
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public VideoDownloader(string? referer, string? cookie = null)
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{
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if (!string.IsNullOrWhiteSpace(referer) && Uri.TryCreate(referer, UriKind.Absolute, out var u)
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&& !string.IsNullOrEmpty(u.Host))
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{
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// 防盗链一般只校来源站点，保留完整路径反而更容易被判定为非法来源；
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// 用 Authority 而不是 Host，带端口的站点把端口去掉后来源就对不上了
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_referer = $"{u.Scheme}://{u.Authority}/";
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}
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if (!string.IsNullOrWhiteSpace(cookie)) _cookie = cookie;
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}
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public static bool IsHlsUrl(string url) =>
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!string.IsNullOrEmpty(url) && Regex.IsMatch(url, @"\.m3u8(\?|#|$)", RegexOptions.IgnoreCase);
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/// <summary>
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/// 判断是否是 HLS 分片（合并播放列表可用，但单独下载没有意义）。
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/// 只认分片特有的后缀与编号形式，不能拿路径里的 video / seg 字样当依据，
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/// 否则 /video/xxx.flv 这种整片地址会被当成分片删掉。
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/// </summary>
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public static bool IsSegmentUrl(string url)
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{
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if (string.IsNullOrEmpty(url)) return false;
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var path = Uri.TryCreate(url, UriKind.Absolute, out var u) ? u.AbsolutePath.ToLowerInvariant() : url.ToLowerInvariant();
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var extension = Path.GetExtension(path);
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// 没有扩展名的地址多为接口型直链（如抖音），当作整片
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if (extension.Length == 0) return false;
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if (WholeVideoExtensions.Any(e => extension == e)) return false;
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return extension is ".ts" or ".m4s" or ".init" or ".m2ts" or ".aac" or ".mp3"
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|| Regex.IsMatch(path, @"(seg|chunk|part|fragment|f)[-_.]?\d+");
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}
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public static bool LooksLikeMedia(string? url)
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{
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if (string.IsNullOrWhiteSpace(url)) return false;
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if (url.StartsWith("blob:", StringComparison.OrdinalIgnoreCase) ||
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url.StartsWith("data:", StringComparison.OrdinalIgnoreCase)) return false;
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if (!Uri.TryCreate(url, UriKind.Absolute, out var u)) return false;
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if (u.Scheme != Uri.UriSchemeHttp && u.Scheme != Uri.UriSchemeHttps) return false;
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var path = u.AbsolutePath.ToLowerInvariant();
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if (Regex.IsMatch(path, @"\.(jpg|jpeg|png|gif|webp|ico|svg|css|js|json|woff2?|ttf|map)$")) return false;
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if (MediaExtensions.Any(e => path.EndsWith(e))) return true;
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return Regex.IsMatch(path, @"/(video|vod|playback|media)[/-]");
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}
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/// <summary>
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/// 根据地址推断保存扩展名；m3u8 会合并成单个文件，有 ffmpeg 时转 mp4，否则输出 ts。
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/// </summary>
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public static string ExtensionFor(string url)
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{
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var raw = RawExtension(url);
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if (raw == ".m3u8" || (raw.Length == 0 && IsHlsUrl(url))) return HasFfmpeg() ? ".mp4" : ".ts";
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if (raw.Length == 0) return ".mp4";
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return raw;
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}
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public static string RawExtension(string url)
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{
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try
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{
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return Path.GetExtension(new Uri(url).AbsolutePath).ToLowerInvariant();
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}
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catch
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{
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return "";
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}
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}
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/// <summary>
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/// 生成建议的文件名：优先用页面标题，其次用地址末段。
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/// </summary>
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public string SuggestedFileName(string url, string? title)
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{
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var name = CleanFileName(title);
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if (string.IsNullOrWhiteSpace(name))
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{
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try
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{
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name = CleanFileName(Path.GetFileNameWithoutExtension(new Uri(url).AbsolutePath));
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}
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catch
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{
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// 忽略，使用兜底名
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}
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}
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if (string.IsNullOrWhiteSpace(name)) name = "video";
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if (name.Length > 60) name = name[..60];
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return name + ExtensionFor(url);
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}
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private static string? CleanFileName(string? text)
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{
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if (string.IsNullOrWhiteSpace(text)) return null;
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var cleaned = Regex.Replace(text, @"[\\/:*?""<>|\r\n\t]", " ").Trim();
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cleaned = Regex.Replace(cleaned, @"\s+", " ");
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return string.IsNullOrWhiteSpace(cleaned) ? null : cleaned;
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}
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/// <summary>
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/// 下载视频。m3u8 会自动挑选最高清晰度并顺序合并分片。
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/// </summary>
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public async Task<DownloadResult> DownloadAsync(string url, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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using var client = CreateClient();
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if (IsHlsUrl(url))
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{
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progress?.Report(new DownloadProgress("解析播放列表…", null));
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var playlist = await ResolvePlaylistAsync(client, url, ct);
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return await WriteHlsAsync(client, playlist, filePath, progress, ct);
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}
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return await DownloadSingleAsync(client, url, filePath, progress, ct);
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}
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/// <summary>
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/// 站点只用 MSE 播放、抓不到 m3u8 地址时，直接拿页面里嗅探到的播放列表文本下载。
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/// </summary>
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public async Task<DownloadResult> DownloadFromPlaylistTextAsync(string playlistText, string baseUrl, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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using var client = CreateClient();
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progress?.Report(new DownloadProgress("解析播放列表…", null));
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var playlist = await ParsePlaylistAsync(playlistText, baseUrl, client, ct, 0);
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return await WriteHlsAsync(client, playlist, filePath, progress, ct);
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}
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private HttpClient CreateClient()
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{
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var client = new HttpClient(new HttpClientHandler { AllowAutoRedirect = false })
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{
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Timeout = TimeSpan.FromMinutes(15)
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};
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client.DefaultRequestHeaders.UserAgent.ParseAdd(UserAgent);
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client.DefaultRequestHeaders.Accept.ParseAdd("*/*");
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client.DefaultRequestHeaders.AcceptLanguage.ParseAdd("zh-CN,zh;q=0.9,en;q=0.8");
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if (_referer != null) client.DefaultRequestHeaders.Referrer = new Uri(_referer);
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if (_cookie != null) client.DefaultRequestHeaders.TryAddWithoutValidation("Cookie", _cookie);
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return client;
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}
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private async Task<DownloadResult> DownloadSingleAsync(HttpClient client, string url, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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using var resp = await GetFollowRedirectAsync(client, url, ct);
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EnsureVideoResponse(resp);
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var total = resp.Content.Headers.ContentLength ?? -1L;
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var part = filePath + ".part";
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Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(filePath))!);
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long done = 0;
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long lastReport = 0;
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await using var input = await resp.Content.ReadAsStreamAsync(ct);
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try
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{
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var buffer = new byte[1024 * 64];
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// 先读一小块验货：防盗链站点经常不报 403，而是给一段 200 的 HTML 错误页
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int read = await input.ReadAsync(buffer.AsMemory(0, 4096), ct);
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if (read > 0) EnsureRealVideoContent(buffer, read, resp, url);
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await using var output = new FileStream(part, FileMode.Create, FileAccess.Write, FileShare.None, 1024 * 64, true);
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while (read > 0)
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{
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await output.WriteAsync(buffer.AsMemory(0, read), ct);
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done += read;
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if (done - lastReport >= 256 * 1024)
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{
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lastReport = done;
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progress?.Report(total > 0
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? new DownloadProgress($"下载中 {FormatSize(done)} / {FormatSize(total)}", done / (double)total)
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: new DownloadProgress($"下载中 {FormatSize(done)}（总大小未知，可点取消结束）", null));
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}
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read = await input.ReadAsync(buffer, ct);
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}
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}
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catch
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{
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TryDelete(part);
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throw;
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}
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MoveIntoPlace(part, filePath);
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progress?.Report(new DownloadProgress($"完成 {FormatSize(done)}", 1));
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return new DownloadResult(filePath, done, false);
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}
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/// <summary>
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/// 把常见 HTTP 错误码翻译成能行动的原因，只说“403”用户不知道下一步该做什么。
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/// </summary>
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private static void EnsureVideoResponse(HttpResponseMessage resp)
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{
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if (resp.IsSuccessStatusCode) return;
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string hint = (int)resp.StatusCode switch
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{
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403 or 401 => "，防盗链或需要登录：先在页面里把视频播起来再点下载，或换一条线路",
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404 => "，地址已失效（这类直链通常只有特别短的有效期）",
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416 => "，服务器不接受当前请求范围，重试即可",
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_ => string.Empty
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};
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throw new HttpRequestException($"服务器返回 {(int)resp.StatusCode} {resp.StatusCode}{hint}");
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}
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/// <summary>
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/// 真正的视频容器不会以 "<" 或 "{" 开头；m3u8 / mpd 本身是文本，不参与检查。
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/// </summary>
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private static void EnsureRealVideoContent(byte[] head, int length, HttpResponseMessage resp, string url)
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{
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if (IsHlsUrl(url) || RawExtension(url) == ".mpd") return;
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var type = resp.Content.Headers.ContentType?.MediaType ?? string.Empty;
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if (type.StartsWith("text/html", StringComparison.OrdinalIgnoreCase)
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|| type.StartsWith("text/plain", StringComparison.OrdinalIgnoreCase)
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|| type.Contains("json", StringComparison.OrdinalIgnoreCase))
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{
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throw new NotSupportedException($"站点返回的是 {type} 而不是视频，多半是防盗链或需要先登录/先播放");
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}
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int i = 0;
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while (i < length && (head[i] is 0xEF or 0xBB or 0xBF or 0x20 or 0x0D or 0x0A or 0x09)) i++;
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if (i < length && (head[i] == (byte)'<' || head[i] == (byte)'{'))
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{
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throw new NotSupportedException("站点返回的是网页内容而不是视频（防盗链或地址已过期），换一条线路重试");
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}
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}
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private static void TryDelete(string path)
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{
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try { if (File.Exists(path)) File.Delete(path); } catch { /* 删不掉不影响报错 */ }
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}
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private async Task<DownloadResult> WriteHlsAsync(HttpClient client, HlsPlaylist playlist, string filePath, IProgress<DownloadProgress>? progress, CancellationToken ct)
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{
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if (playlist.Segments.Count == 0)
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throw new InvalidOperationException("播放列表里没有解析到视频分片，可能还在加载中，请稍后重试");
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if (playlist.KeyLine != null && playlist.KeyLine.Contains("METHOD=", StringComparison.OrdinalIgnoreCase)
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&& !playlist.KeyLine.Contains("METHOD=NONE", StringComparison.OrdinalIgnoreCase))
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{
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throw new NotSupportedException($"该视频是加密 HLS（{playlist.KeyLine}），需要解密 Key，暂不支持自动下载");
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}
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// 分片直接拼接出来的是 .ts；装了 ffmpeg 时顺手无损转封装成 mp4，播放更通用
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var wantsMp4 = string.Equals(Path.GetExtension(filePath), ".mp4", StringComparison.OrdinalIgnoreCase);
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var ffmpeg = wantsMp4 ? FindFfmpeg() : null;
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if (wantsMp4 && ffmpeg == null)
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{
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// 没有 ffmpeg 就不能把 ts 流写成 .mp4 后缀，否则很多播放器认不出来
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filePath = Path.ChangeExtension(filePath, ".ts");
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progress?.Report(new DownloadProgress("未找到 ffmpeg，改存为 .ts（播放器可以直接播）", null));
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}
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var mergedPath = ffmpeg != null
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? Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString("N") + ".ts")
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: filePath;
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Directory.CreateDirectory(Path.GetDirectoryName(Path.GetFullPath(mergedPath))!);
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long total = 0;
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int index = 0;
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var part = mergedPath + ".part";
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await using (var output = new FileStream(part, FileMode.Create, FileAccess.Write, FileShare.None, 1024 * 1024, true))
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{
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foreach (var segment in playlist.Segments)
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{
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ct.ThrowIfCancellationRequested();
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using var resp = await GetFollowRedirectAsync(client, segment, ct);
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resp.EnsureSuccessStatusCode();
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await using var input = await resp.Content.ReadAsStreamAsync(ct);
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await input.CopyToAsync(output, ct);
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total += resp.Content.Headers.ContentLength ?? 0;
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index++;
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if (index % 5 == 0 || index == playlist.Segments.Count)
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progress?.Report(new DownloadProgress($"下载分片 {index}/{playlist.Segments.Count}，已下载 {FormatSize(total)}", index / (double)playlist.Segments.Count));
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}
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}
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if (ffmpeg == null)
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{
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MoveIntoPlace(part, mergedPath);
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progress?.Report(new DownloadProgress($"完成 {FormatSize(total)}", 1));
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return new DownloadResult(mergedPath, new FileInfo(mergedPath).Length, false);
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}
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progress?.Report(new DownloadProgress("用 ffmpeg 转封装为 mp4…", null));
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MoveIntoPlace(part, mergedPath);
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try
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{
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var ok = await ConvertToMp4Async(ffmpeg, mergedPath, filePath, ct);
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if (ok)
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{
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try { File.Delete(mergedPath); } catch { /* 临时文件删不掉不影响结果 */ }
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var size = new FileInfo(filePath).Length;
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progress?.Report(new DownloadProgress($"完成 {FormatSize(size)}", 1));
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return new DownloadResult(filePath, size, true);
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}
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}
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catch
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{
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// 转封装失败时保留 ts 文件，避免用户什么都拿不到
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}
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var tsSize = new FileInfo(mergedPath).Length;
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progress?.Report(new DownloadProgress($"完成（未能转成 mp4，已保存 ts）{FormatSize(tsSize)}", 1));
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return new DownloadResult(mergedPath, tsSize, false);
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}
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private record HlsPlaylist(List<string> Segments, string? KeyLine);
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/// <summary>
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/// 解析 m3u8：主播放列表按带宽挑最高清晰度，最后返回绝对地址的分片列表。
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/// </summary>
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private async Task<HlsPlaylist> ResolvePlaylistAsync(HttpClient client, string url, CancellationToken ct, int depth = 0)
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{
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if (depth > 3) throw new InvalidOperationException("播放列表嵌套层级过深");
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using var resp = await GetFollowRedirectAsync(client, url, ct);
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resp.EnsureSuccessStatusCode();
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var text = await ReadTextAsync(resp, ct);
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return await ParsePlaylistAsync(text, url, client, ct, depth);
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}
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private async Task<HlsPlaylist> ParsePlaylistAsync(string text, string url, HttpClient client, CancellationToken ct, int depth)
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{
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if (!text.Contains("#EXTM3U"))
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throw new InvalidOperationException("返回的内容不是 m3u8 播放列表，请改用列表里的 mp4 直链下载");
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var lines = text.Split('\n').Select(l => l.Trim('\r', ' ', '\t')).ToList();
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// 主播放列表：#EXT-X-STREAM-INF 后面紧跟子列表地址
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var variants = new List<(string Uri, int Bandwidth)>();
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for (int i = 0; i < lines.Count; i++)
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{
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if (!lines[i].StartsWith("#EXT-X-STREAM-INF", StringComparison.OrdinalIgnoreCase)) continue;
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var bandwidth = 0;
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var m = Regex.Match(lines[i], @"BANDWIDTH=(\d+)", RegexOptions.IgnoreCase);
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if (m.Success) bandwidth = int.Parse(m.Groups[1].Value);
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for (int j = i + 1; j < lines.Count; j++)
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{
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if (lines[j].Length == 0 || lines[j].StartsWith("#")) continue;
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variants.Add((lines[j], bandwidth));
|
||
break;
|
||
}
|
||
}
|
||
|
||
if (variants.Count > 0)
|
||
{
|
||
var best = variants[^1];
|
||
foreach (var v in variants)
|
||
if (v.Bandwidth > best.Bandwidth) best = v;
|
||
|
||
ct.ThrowIfCancellationRequested();
|
||
return await ResolvePlaylistAsync(client, Resolve(url, best.Uri), ct, depth + 1);
|
||
}
|
||
|
||
var segments = lines
|
||
.Where(l => l.Length > 0 && !l.StartsWith("#"))
|
||
.Select(l => Resolve(url, l))
|
||
.ToList();
|
||
|
||
var keyLine = lines.FirstOrDefault(l => l.StartsWith("#EXT-X-KEY", StringComparison.OrdinalIgnoreCase));
|
||
return new HlsPlaylist(segments, keyLine);
|
||
}
|
||
|
||
private static string Resolve(string baseUrl, string relative)
|
||
{
|
||
if (Path.IsPathRooted(relative) || relative.StartsWith("//", StringComparison.Ordinal))
|
||
{
|
||
try
|
||
{
|
||
var u = new Uri(baseUrl);
|
||
return $"{u.Scheme}:{relative}";
|
||
}
|
||
catch
|
||
{
|
||
return relative;
|
||
}
|
||
}
|
||
|
||
if (Uri.TryCreate(relative, UriKind.Absolute, out _)) return relative;
|
||
|
||
try
|
||
{
|
||
return new Uri(new Uri(baseUrl), relative).ToString();
|
||
}
|
||
catch
|
||
{
|
||
return relative;
|
||
}
|
||
}
|
||
|
||
private static async Task<HttpResponseMessage> GetFollowRedirectAsync(HttpClient client, string url, CancellationToken ct)
|
||
{
|
||
var current = url;
|
||
HttpResponseMessage? previous = null;
|
||
|
||
for (int i = 0; i < 6; i++)
|
||
{
|
||
var resp = await client.GetAsync(current, HttpCompletionOption.ResponseHeadersRead, ct);
|
||
|
||
if (resp.IsSuccessStatusCode) return resp;
|
||
|
||
var status = (int)resp.StatusCode;
|
||
var location = resp.Headers.Location;
|
||
if (status < 300 || status > 399 || location == null) return resp;
|
||
|
||
previous?.Dispose();
|
||
previous = resp;
|
||
current = location.IsAbsoluteUri ? location.ToString() : new Uri(new Uri(current), location).ToString();
|
||
}
|
||
|
||
return previous ?? await client.GetAsync(current, HttpCompletionOption.ResponseHeadersRead, ct);
|
||
}
|
||
|
||
/// <summary>
|
||
/// m3u8 常用 GBK 编码，直接按 UTF8 读会让中文路径的分片地址出错。
|
||
/// </summary>
|
||
private static async Task<string> ReadTextAsync(HttpResponseMessage resp, CancellationToken ct)
|
||
{
|
||
using var ms = new MemoryStream();
|
||
await resp.Content.CopyToAsync(ms, ct);
|
||
|
||
var encoding = Encoding.UTF8;
|
||
var match = CharsetRx.Match(resp.Content.Headers.ContentType?.ToString() ?? "");
|
||
if (match.Success)
|
||
{
|
||
try { encoding = Encoding.GetEncoding(match.Groups[1].Value); }
|
||
catch { /* 未知编码退回 UTF8 */ }
|
||
}
|
||
|
||
var text = encoding.GetString(ms.ToArray());
|
||
|
||
// 去掉可能存在的 BOM
|
||
if (text.Length > 0 && text[0] == '\uFEFF') text = text[1..];
|
||
return text;
|
||
}
|
||
|
||
private static async Task<bool> ConvertToMp4Async(string ffmpeg, string tsFile, string mp4File, CancellationToken ct)
|
||
{
|
||
var args = $"-hide_banner -loglevel error -y -fflags +genpts -i \"{tsFile}\" -c copy -bsf:a aac_adtstoasc -movflags +faststart \"{mp4File}\"";
|
||
var psi = new ProcessStartInfo
|
||
{
|
||
FileName = ffmpeg,
|
||
Arguments = args,
|
||
UseShellExecute = false,
|
||
CreateNoWindow = true,
|
||
RedirectStandardError = true,
|
||
RedirectStandardOutput = true
|
||
};
|
||
|
||
using var proc = Process.Start(psi);
|
||
if (proc == null) return false;
|
||
|
||
using (ct.Register(() => { try { if (!proc.HasExited) proc.Kill(true); } catch { } }))
|
||
{
|
||
await proc.WaitForExitAsync(ct);
|
||
}
|
||
|
||
return proc.ExitCode == 0 && File.Exists(mp4File) && new FileInfo(mp4File).Length > 0;
|
||
}
|
||
|
||
/// <summary>
|
||
/// 查找 ffmpeg：先看程序目录，再看 PATH。找到就能把 HLS 转成 mp4，找不到则只合并 ts。
|
||
/// </summary>
|
||
public static string? FindFfmpeg()
|
||
{
|
||
var local = Path.Combine(AppContext.BaseDirectory, "ffmpeg.exe");
|
||
if (File.Exists(local)) return local;
|
||
|
||
foreach (var dir in (Environment.GetEnvironmentVariable("PATH") ?? "").Split(Path.PathSeparator))
|
||
{
|
||
if (string.IsNullOrWhiteSpace(dir)) continue;
|
||
try
|
||
{
|
||
var candidate = Path.Combine(dir.Trim().Trim('"'), "ffmpeg.exe");
|
||
if (File.Exists(candidate)) return candidate;
|
||
}
|
||
catch
|
||
{
|
||
// PATH 里存在非法字符时跳过该项
|
||
}
|
||
}
|
||
|
||
return null;
|
||
}
|
||
|
||
public static bool HasFfmpeg() => FindFfmpeg() != null;
|
||
|
||
private static void MoveIntoPlace(string partFile, string targetFile)
|
||
{
|
||
if (File.Exists(targetFile)) File.Delete(targetFile);
|
||
File.Move(partFile, targetFile);
|
||
}
|
||
|
||
public static string FormatSize(long bytes)
|
||
{
|
||
if (bytes <= 0) return "0 B";
|
||
if (bytes >= 1L << 30) return $"{bytes / (double)(1L << 30):0.00} GB";
|
||
if (bytes >= 1L << 20) return $"{bytes / (double)(1L << 20):0.0} MB";
|
||
if (bytes >= 1L << 10) return $"{bytes / (double)(1L << 10):0.0} KB";
|
||
return $"{bytes} B";
|
||
}
|
||
}
|
||
}
|