考慮到請求和響應範圍標頭，如何流式傳輸影片或文件？

我現在正在使用FileStreamResult它，它可以流式傳輸影片，但無法尋找它。它總是從頭開始。

我正在使用ByteRangeStreamContent，但它似乎不再適用於dnxcore50.

那麼如何進行呢？

我是否需要手動解析請求範圍標頭並編寫一個自定義FileResult來設置響應Content-Range和其餘標頭並將緩衝區範圍寫入響應正文，或者是否已經實現了某些東西並且我錯過了它？

這是 a 的簡單實現VideoStreamResult。我目前正在使用（未測試多部分內容部分）：

public class VideoStreamResult : FileStreamResult
{
   // default buffer size as defined in BufferedStream type
   private const int BufferSize = 0x1000;
   private string MultipartBoundary = "<qwe123>";

   public VideoStreamResult(Stream fileStream, string contentType)
       : base(fileStream, contentType)
   {
       
   }

   public VideoStreamResult(Stream fileStream, MediaTypeHeaderValue contentType) 
       : base(fileStream, contentType)
   {

   }

   private bool IsMultipartRequest(RangeHeaderValue range)
   {
       return range != null && range.Ranges != null && range.Ranges.Count > 1;
   }

   private bool IsRangeRequest(RangeHeaderValue range)
   {
       return range != null && range.Ranges != null && range.Ranges.Count > 0;
   }

   protected async Task WriteVideoAsync(HttpResponse response)
   {
       var bufferingFeature = response.HttpContext.Features.Get<IHttpBufferingFeature>();
       bufferingFeature?.DisableResponseBuffering();

       var length = FileStream.Length;

       var range = response.HttpContext.GetRanges(length);

       if (IsMultipartRequest(range))
       {
           response.ContentType = $"multipart/byteranges; boundary={MultipartBoundary}";
       }
       else
       {
           response.ContentType = ContentType.ToString();
       }

       response.Headers.Add("Accept-Ranges", "bytes");

       if (IsRangeRequest(range))
       {
           response.StatusCode = (int)HttpStatusCode.PartialContent;

           if (!IsMultipartRequest(range))
           {
               response.Headers.Add("Content-Range", $"bytes {range.Ranges.First().From}-{range.Ranges.First().To}/{length}");
           }

           foreach (var rangeValue in range.Ranges)
           {
               if (IsMultipartRequest(range)) // I don't know if multipart works
               {
                   await response.WriteAsync($"--{MultipartBoundary}");
                   await response.WriteAsync(Environment.NewLine);
                   await response.WriteAsync($"Content-type: {ContentType}");
                   await response.WriteAsync(Environment.NewLine);
                   await response.WriteAsync($"Content-Range: bytes {range.Ranges.First().From}-{range.Ranges.First().To}/{length}");
                   await response.WriteAsync(Environment.NewLine);
               }

               await WriteDataToResponseBody(rangeValue, response);

               if (IsMultipartRequest(range))
               {
                   await response.WriteAsync(Environment.NewLine);
               }
           }

           if (IsMultipartRequest(range))
           {
               await response.WriteAsync($"--{MultipartBoundary}--");
               await response.WriteAsync(Environment.NewLine);
           }
       }
       else
       {
           await FileStream.CopyToAsync(response.Body);
       }
   }

   private async Task WriteDataToResponseBody(RangeItemHeaderValue rangeValue, HttpResponse response)
   {
       var startIndex = rangeValue.From ?? 0;
       var endIndex = rangeValue.To ?? 0;

       byte[] buffer = new byte[BufferSize];
       long totalToSend = endIndex - startIndex;
       int count = 0;

       long bytesRemaining = totalToSend + 1;
       response.ContentLength = bytesRemaining;

       FileStream.Seek(startIndex, SeekOrigin.Begin);

       while (bytesRemaining > 0)
       {
           try
           {
               if (bytesRemaining <= buffer.Length)
                   count = FileStream.Read(buffer, 0, (int)bytesRemaining);
               else
                   count = FileStream.Read(buffer, 0, buffer.Length);

               if (count == 0)
                   return;

               await response.Body.WriteAsync(buffer, 0, count);

               bytesRemaining -= count;
           }
           catch (IndexOutOfRangeException)
           {
               await response.Body.FlushAsync();
               return;
           }
           finally
           {
               await response.Body.FlushAsync();
           }
       }
   }

   public override async Task ExecuteResultAsync(ActionContext context)
   {
       await WriteVideoAsync(context.HttpContext.Response);
   }
}

並解析請求標頭範圍：

public static RangeHeaderValue GetRanges(this HttpContext context, long contentSize)
       {
           RangeHeaderValue rangesResult = null;

           string rangeHeader = context.Request.Headers["Range"];

           if (!string.IsNullOrEmpty(rangeHeader))
           {
               // rangeHeader contains the value of the Range HTTP Header and can have values like:
               //      Range: bytes=0-1            * Get bytes 0 and 1, inclusive
               //      Range: bytes=0-500          * Get bytes 0 to 500 (the first 501 bytes), inclusive
               //      Range: bytes=400-1000       * Get bytes 500 to 1000 (501 bytes in total), inclusive
               //      Range: bytes=-200           * Get the last 200 bytes
               //      Range: bytes=500-           * Get all bytes from byte 500 to the end
               //
               // Can also have multiple ranges delimited by commas, as in:
               //      Range: bytes=0-500,600-1000 * Get bytes 0-500 (the first 501 bytes), inclusive plus bytes 600-1000 (401 bytes) inclusive

               // Remove "Ranges" and break up the ranges
               string[] ranges = rangeHeader.Replace("bytes=", string.Empty).Split(",".ToCharArray());

               rangesResult = new RangeHeaderValue();

               for (int i = 0; i < ranges.Length; i++)
               {
                   const int START = 0, END = 1;

                   long endByte, startByte;

                   long parsedValue;

                   string[] currentRange = ranges[i].Split("-".ToCharArray());

                   if (long.TryParse(currentRange[END], out parsedValue))
                       endByte = parsedValue;
                   else
                       endByte = contentSize - 1;


                   if (long.TryParse(currentRange[START], out parsedValue))
                       startByte = parsedValue;
                   else
                   {
                       // No beginning specified, get last n bytes of file
                       // We already parsed end, so subtract from total and
                       // make end the actual size of the file
                       startByte = contentSize - endByte;
                       endByte = contentSize - 1;
                   }

                   rangesResult.Ranges.Add(new RangeItemHeaderValue(startByte, endByte));
               }
           }

           return rangesResult;
       }

引用自：https://stackoverflow.com/questions/34047247