İndirme yöneticisi - limit indirme hızı

Question

Dosya indirici uygulamam için bir indirme hızı sınırı uygulamam gerekiyor ve CodeProject'ten ThrottledStream sınıfına baktım ama bu durum benim durumumda çalışmayacak çünkü indirme sırasında sınırı değiştirmek için, sadece başında değil.

webResponse = (HttpWebResponse)webRequest.GetResponse(); 
responseStream = webResponse.GetResponseStream(); 
responseStream.ReadTimeout = 5000; 

downloadCache = new MemoryStream(this.MaxCacheSize); 
byte[] downloadBuffer = new byte[this.BufferSize]; 
int bytesSize = 0; 
CachedSize = 0; 
int receivedBufferCount = 0; 

while (true) 
{ 
    bytesSize = responseStream.Read(downloadBuffer, 0, downloadBuffer.Length); 

    if (this.Status != DownloadStatus.Downloading || bytesSize == 0 
     || this.MaxCacheSize < CachedSize + bytesSize) 
    { 
     WriteCacheToFile(downloadCache, CachedSize); 

     this.DownloadedSize += CachedSize; 
     downloadCache.Seek(0, SeekOrigin.Begin); 
     CachedSize = 0; 

     if (this.Status != DownloadStatus.Downloading || bytesSize == 0) 
      break; 
    } 

    downloadCache.Write(downloadBuffer, 0, bytesSize); 
    CachedSize += bytesSize; 

    receivedBufferCount++; 
    if (receivedBufferCount == this.BufferCountPerNotification) 
    { 
     this.RaiseDownloadProgressChanged(); 
     receivedBufferCount = 0; 
    } 
} 

Ben ettik Thread.Sleep() veya Thread.Wait(), ama iyi bir fikirdir kullanarak da görülen insan: İşte bir arka plan iş parçacığı kullanıyorum indirme yönteminin bir parçası değil mi? Bu süre içinde bunu nasıl yapabileceğimi önerilerin var mı? Bunun sana yararlıdır olabilir sunucudan dosya indirmek için bu kodu kullanmış

Answer 1

...

private bool DownLoadFile(string pstrFileName, string pstrFilePath, long plngFileSize) 
    { 
     try 
     { 
      string strNewFileSize = CalcFileSize(plngFileSize); 
      int numIterations = 0; // this is used with a modulus of the sampleInterval to check if the chunk size should be adjusted. it is started at 1 so that the first check will be skipped because it may involve an initial delay in connecting to the web service 
      Offset = 0; 
      long webConfigSetting = this.mobjService.GetMaxRequestLength(); 
      this.MaxRequestLength = Math.Max(1, (webConfigSetting * 1024) - (2 * 1024)); // set the max buffer size to slightly less than the request length to allow for SOAP message headers etc. 
      if (File.Exists(pstrFilePath)) 
      { 
       Offset = new FileInfo(pstrFilePath).Length; 
       if (Offset == plngFileSize) 
        Offset = 0; 
       //File.Delete(pstrFilePath); 
      } 
      if (Offset == 0 && !File.Exists(pstrFilePath)) // create a new empty file 
       File.Create(pstrFilePath).Close(); 

      // open a file stream for the file we will write to in the start-up folder 
      lblFileName.Text = pstrFileName.Substring(0, pstrFileName.LastIndexOf(".")).Replace("&", "&&"); 
      using (FileStream fs = new FileStream(pstrFilePath, FileMode.OpenOrCreate, FileAccess.Write)) 
      { 
       pbrSummary.Maximum = (int)plngFileSize; 
       fs.Seek(Offset, SeekOrigin.Begin); 
       // download the chunks from the web service one by one, until all the bytes have been read, meaning the entire file has been downloaded. 
       while (Offset < plngFileSize) 
       { 
        int currentIntervalMod = numIterations % this.ChunkSizeSampleInterval; 
        if (currentIntervalMod == 0) 
         StartTime = DateTime.Now; // used to calculate the time taken to transfer the first 5 chunks 
        else if (currentIntervalMod == 1) 
         CalcAndSetChunkSize(plngFileSize); 
        try 
        { 
         // although the DownloadChunk returns a byte[], it is actually sent using MTOM because of the configuration settings. 
         byte[] Buffer = mobjService.DownloadChunk(pstrFileName, Offset, ChunkSize); 
         fs.Write(Buffer, 0, Buffer.Length); 
         Offset += Buffer.Length; // save the offset position for resume 
        } 
        catch (Exception ex) 
        { 
         if (ex.Message.Contains("File not found") || NumRetries++ >= MaxRetries) // too many retries, bail out 
         { 
          fs.Close(); 
          return false; 
          //throw new Exception("Error occurred during upload, too many retries.\r\n" + ex.Message); 
         } 
        } 
        numIterations++; 
        //----------------------- Code Commented ------------------------ 
        //lblDownload.Text = CalcFileSize(Offset) + " of " + strNewFileSize; 
        //lblRate.Text = CalcFileSize(ChunkSize)+"/sec"; 
        ////pbrSummary.Value = (int)Offset; 
        ////if ((int)Offset <= pbrSummary.Maximum) 
        //// pbrSummary.Value = (int)Offset; 
        ////else 
        //// pbrSummary.Value = pbrSummary.Maximum; 
        //------------------------------------------------------------------ 
       } 
      } 
      return true; 
     } 
     catch (Exception Exc) 
     { 
      throw (Exc); 
     } 
    } 
    private void CalcAndSetChunkSize(long plngFileSize) 
    { 
     /* chunk size calculation is defined as follows 
     *  in the examples below, the preferred transfer time is 1500ms, taking one sample. 
     *  
     *         Example 1         Example 2 
     *  Initial size    = 16384 bytes (16k)      16384 
     *  Transfer time for 1 chunk = 800ms          2000 ms 
     *  Average throughput/ms  = 16384b/800ms = 20.48 b/ms    16384/2000 = 8.192 b/ms 
     *  How many bytes in 1500ms? = 20.48 * 1500 = 30720 bytes    8.192 * 1500 = 12228 bytes 
     *  New chunksize    = 30720 bytes (speed up)     12228 bytes (slow down from original chunk size) 
     */ 
     double transferTime = DateTime.Now.Subtract(this.StartTime).TotalMilliseconds; 
     double averageBytesPerMilliSec = this.ChunkSize/transferTime; 
     double preferredChunkSize = averageBytesPerMilliSec * this.PreferredTransferDuration; 
     this.ChunkSize = (int)Math.Min(this.MaxRequestLength, Math.Max(4 * 1024, preferredChunkSize)) * 10; // set the chunk size so that it takes 1500ms per chunk (estimate), not less than 4Kb and not greater than 4mb // (note 4096Kb sometimes causes problems, probably due to the IIS max request size limit, choosing a slightly smaller max size of 4 million bytes seems to work nicely)   

     //string statusMessage = String.Format("Chunk size: {0}{1}", CalcFileSize(this.ChunkSize), (this.ChunkSize == this.MaxRequestLength) ? " (max)" : ""); 
    }