Question

我有以下方法使用httpwebrequest从网址下载文件。我正在下载列表中包含的150个文件。这可能需要最多30分钟。当我运行我的服务时，我的网络请求不断超时，我不确定为什么？我猜它正在创建150个任务并尽可能多地处理，但在某些任务的超时期限之后超时。我的方法发生了什么？

try
{
     //Download File here
     Task t = new Task(() =>
     {
         byte[] lnBuffer;
         byte[] lnFile;
         HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(string.Format("{0}/{1}", Settings1.Default.WebPhotosLocation, f.FileName));
//Breaks on the line below
         using (HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse())
         {
              httpWebRequest.Timeout = 14400000;
              httpWebRequest.KeepAlive = true;
              using (BinaryReader binaryReader = new BinaryReader(httpWebResponse.GetResponseStream()))
              {
                    using (MemoryStream memoryStream = new MemoryStream())
                    {
                          lnBuffer = binaryReader.ReadBytes(1024);
                          while (lnBuffer.Length > 0)
                          {
                                memoryStream.Write(lnBuffer, 0, lnBuffer.Length);
                                lnBuffer = binaryReader.ReadBytes(1024);
                          }
                          lnFile = new byte[(int)memoryStream.Length];
                          memoryStream.Position = 0;
                          memoryStream.Read(lnFile, 0, lnFile.Length);
                    }
               }
         }
         using (System.IO.FileStream lxFS = new FileStream(string.Format(@"{0}\{1}", fileDirectory, f.FileName), FileMode.Create))
         {
               lxFS.Write(lnFile, 0, lnFile.Length);
         }
         Log.WriteLine(string.Format("Downloaded File: {0}", f.FullName), Log.Status.Success);
         filesDownloaded++;
     });
     t.Start();
     listOfTasks.Add(t);
}
catch (Exception ex)
{
     Log.WriteLine(string.Format("There has been an error Downloading File {0}. Error: {1}", f.FullName, ex), Log.Status.Error);
     throw;
}

修改

在代码中声明的行抛出异常：

异常：类型＆＃39; System.Net.WebException＆＃39;的例外情况发生在   System.dll但未在用户代码中处理

其他信息：操作已超时

首次下载开始后3分20秒后抛出错误

Answer 1

原来我在调用GetResponse后设置了Timeout值。将超时置于此方法调用之上是完美的。

HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(string.Format("{0}/{1}", Settings1.Default.WebPhotosLocation, f.FileName));
httpWebRequest.Timeout = 14400000;
httpWebRequest.KeepAlive = true;
using (HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse())
{
    //Do stuff
}

从httpwebrequest异步下载文件会引发超时错误

1 个答案: