WebRequest.GetRequestStream和LOH

Question

我使用下面的代碼將大文件上傳到服務器，並注意到將FileStream複製到GetRequestStream的bytes數組被創建並保存在內存中。這增加了大對象堆，我不想要它。也許有人知道如何解決這個問題？

Stream formData = new FileStream(.....) 

    HttpWebRequest request = WebRequest.Create(postUrl) as HttpWebRequest; 
    using (Stream requestStream = request.GetRequestStream()) 
    {    
    Helpers.CopyStream(formData, requestStream); 
    requestStream.Close(); 
    } 

    public static void CopyStream(Stream fromStream, Stream toStream) 
      { 
       try 
       { 
        int bytesRead; 
        byte[] buffer = new byte[32768]; 
        while (fromStream != null && (bytesRead = fromStream.Read(buffer, 0, buffer.Length)) > 0) 
        { 
         toStream.Write(buffer, 0, bytesRead); 
        } 
       } 
       catch (IOException) 
       { 
        //suppress empty stream response 
       } 
      } 

Memory profiler graph。字節數組中GetRequestStream

內部創建

Answer 1

可以使用HttpWebRequest.AllowWriteStreamBuffering禁用內部緩衝：

HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest; 

    request.AllowWriteStreamBuffering = false; 

    using (Stream formData = File.Open(fileName, FileMode.Open)) 
    using (Stream requestStream = request.GetRequestStream()) 
    { 
     formData.CopyTo(requestStream, 32768); 
    }