支持单文件多线程下载

src/N_m3u8DL-RE/CommandLine/CommandInvoker.cs

@@ -18,7 +18,7 @@ namespace N_m3u8DL_RE.CommandLine
 {
     internal partial class CommandInvoker
     {
-        public const string VERSION_INFO = "N_m3u8DL-RE (Beta version) 20230412";
+        public const string VERSION_INFO = "N_m3u8DL-RE (Beta version) 20230601";
 
         [GeneratedRegex("((best|worst)\\d*|all)")]
         private static partial Regex ForStrRegex();

src/N_m3u8DL-RE/DownloadManager/SimpleDownloadManager.cs

@@ -107,7 +107,13 @@ namespace N_m3u8DL_RE.DownloadManager
 
             var segments = streamSpec.Playlist?.MediaParts.SelectMany(m => m.MediaSegments);
             if (segments == null || !segments.Any()) return false;
-            if (segments.Count() == 1) speedContainer.SingleSegment = true;
+            //单分段尝试切片并行下载
+            if (segments.Count() == 1)
+            {
+                var splitSegments = await LargeSingleFileSplitUtil.SplitUrlAsync(segments.First(), DownloaderConfig.Headers);
+                if (splitSegments != null) segments = splitSegments;
+                else speedContainer.SingleSegment = true;
+            }
 
             var type = streamSpec.MediaType ?? Common.Enum.MediaType.VIDEO;
             var dirName = $"{DownloaderConfig.MyOptions.SaveName ?? NowDateTime.ToString("yyyy-MM-dd_HH-mm-ss")}_{task.Id}_{OtherUtil.GetValidFileName(streamSpec.GroupId ?? "", "-")}_{streamSpec.Codecs}_{streamSpec.Bandwidth}_{streamSpec.Language}";

src/N_m3u8DL-RE/Util/LargeSingleFileSplitUtil.cs

@@ -0,0 +1,122 @@
+using N_m3u8DL_RE.Common.Entity;
+using N_m3u8DL_RE.Common.Log;
+using N_m3u8DL_RE.Common.Util;
+using NiL.JS.Expressions;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net.Http;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace N_m3u8DL_RE.Util
+{
+    internal class LargeSingleFileSplitUtil
+    {
+        class Clip
+        {
+            public required int index;
+            public required long from;
+            public required long to;
+        }
+
+        /// <summary>
+        /// URL大文件切片处理
+        /// </summary>
+        /// <param name="url"></param>
+        /// <param name="headers"></param>
+        /// <param name="splitSegments"></param>
+        /// <returns></returns>
+        public static async Task<List<MediaSegment>?> SplitUrlAsync(MediaSegment segment, Dictionary<string,string> headers)
+        {
+            var url = segment.Url;
+            if (!await CanSplitAsync(url, headers)) return null;
+
+            if (segment.StartRange != null) return null;
+
+            long fileSize = await GetFileSizeAsync(url, headers);
+            if (fileSize == 0) return null;
+
+            List<Clip> allClips = GetAllClips(url, fileSize);
+            var splitSegments = new List<MediaSegment>();
+            foreach (Clip clip in allClips)
+            {
+                splitSegments.Add(new MediaSegment()
+                {
+                    Index = clip.index,
+                    Url = url,
+                    StartRange = clip.from,
+                    ExpectLength = clip.to == -1 ? null : clip.to - clip.from + 1,
+                    EncryptInfo = segment.EncryptInfo,
+                });
+            }
+
+            return splitSegments;
+        }
+
+        public static async Task<bool> CanSplitAsync(string url, Dictionary<string, string> headers)
+        {
+            try
+            {
+                var request = new HttpRequestMessage(HttpMethod.Head, url);
+                var response = (await HTTPUtil.AppHttpClient.SendAsync(request, HttpCompletionOption.ResponseHeadersRead)).EnsureSuccessStatusCode();
+                bool supportsRangeRequests = response.Headers.Contains("Accept-Ranges");
+
+                return supportsRangeRequests;
+            }
+            catch (Exception ex)
+            {
+                Logger.DebugMarkUp(ex.Message);
+                return false;
+            }
+        }
+
+        private static async Task<long> GetFileSizeAsync(string url, Dictionary<string, string> headers)
+        {
+            using var httpRequestMessage = new HttpRequestMessage();
+            httpRequestMessage.RequestUri = new(url);
+            foreach (var header in headers)
+            {
+                httpRequestMessage.Headers.TryAddWithoutValidation(header.Key, header.Value);
+            }
+            var response = (await HTTPUtil.AppHttpClient.SendAsync(httpRequestMessage, HttpCompletionOption.ResponseHeadersRead)).EnsureSuccessStatusCode();
+            long totalSizeBytes = response.Content.Headers.ContentLength ?? 0;
+
+            return totalSizeBytes;
+        }
+
+        //此函数主要是切片下载逻辑
+        private static List<Clip> GetAllClips(string url, long fileSize)
+        {
+            List<Clip> clips = new();
+            int index = 0;
+            long counter = 0;
+            int perSize = 10 * 1024 * 1024;
+            while (fileSize > 0)
+            {
+                Clip c = new()
+                {
+                    index = index,
+                    from = counter,
+                    to = counter + perSize
+                };
+                //没到最后
+                if (fileSize - perSize > 0)
+                {
+                    fileSize -= perSize;
+                    counter += perSize + 1;
+                    index++;
+                    clips.Add(c);
+                }
+                //已到最后
+                else
+                {
+                    c.to = -1;
+                    clips.Add(c);
+                    break;
+                }
+            }
+            return clips;
+        }
+    }
+}