c# - HttpWebRequest超时处理

Question

我有一个非常简单的问题。我正在使用 HTTP POST 将文件上传到服务器。问题是我需要专门处理连接超时，并在发生超时后添加一些等待算法以重新启动服务器。

我的代码很简单:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("SomeURI");
request.Method = "POST";
request.ContentType = "application/octet-stream";
request.KeepAlive = true;
request.Accept = "*/*";
request.Timeout = 300000;
request.AllowWriteStreamBuffering = false;

try
{
      using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
      {
            WebHeaderCollection headers = response.Headers;    
            using (Stream Answer = response.GetResponseStream())
            {
                // Handle.
            }
      }
}
catch (WebException e)
{
    if (Timeout_exception)
    {
       //Handle timeout exception
    }
}

我省略了文件读取代码，因为这与我们无关。现在我需要确保一旦抛出 WebException，我就会过滤该异常以查看它是否确实是超时异常。我考虑过与异常消息进行比较，但我不确定这是否是正确的方法，因为有问题的应用程序是商业应用程序，而且我担心消息会因不同语言而异。我应该寻找什么消息。

有什么建议吗？

Answer 1

可以看看WebException.Status . WebExceptionStatus 枚举有一个 Timeout 标志:

try
{
   using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
   {
      WebHeaderCollection headers = response.Headers;    
      using (Stream answer = response.GetResponseStream())
      {
          // Do stuff
      }
   }
}
catch (WebException e)
{
   if (e.Status == WebExceptionStatus.Timeout)
   {
      // Handle timeout exception
   }
   else throw;
}

使用 C# 6 异常过滤器在这里可以派上用场:

try
{
    var request = WebRequest.Create("http://www.google.com");
    using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
    {
        WebHeaderCollection headers = response.Headers;
        using (Stream answer = response.GetResponseStream())
        {
            // Do stuff
        }
    }
}
catch (WebException e) when (e.Status == WebExceptionStatus.Timeout)
{
    // If we got here, it was a timeout exception.
}