将数据发布到 HTTPS url 时，GetRequestStream() 抛出超时异常

Question

我正在调用托管在 Apache 服务器上的 API 来发布数据。我正在使用 HttpWebRequest 在 C# 中执行 POST。

API 在服务器上同时具有普通 HTTP 和安全层 (HTTPS) 端口。当我调用 HTTP URL 时，它工作得很好。但是，当我调用 HTTPS 时，它会给我超时异常（在 GetRequestStream() 函数中）。有什么见解吗？我正在使用 VS 2010、.Net 框架 3.5 和 C#。这是代码块：

string json_value = jsonSerializer.Serialize(data);


        HttpWebRequest request = (HttpWebRequest)System.Net.WebRequest.Create("https://server-url-xxxx.com");
        request.Method = "POST";
        request.ProtocolVersion = System.Net.HttpVersion.Version10;
        request.ContentType = "application/x-www-form-urlencoded";

        byte[] buffer = Encoding.ASCII.GetBytes(json_value);
        request.ContentLength = buffer.Length;
        System.IO.Stream reqStream = request.GetRequestStream();
        reqStream.Write(buffer, 0, buffer.Length);
        reqStream.Close();

编辑： Peter 建议的控制台程序运行良好。但是当我添加需要发布到 API 的数据（JSON 格式）时，它会抛出操作超时异常。这是我添加到基于控制台的应用程序的代码，它会引发错误。

byte[] buffer = Encoding.ASCII.GetBytes(json_value);
request.ContentLength = buffer.Length;

Answer 1

我遇到了同样的问题。似乎它为我解决了。我检查了所有代码，确保为我的所有 HttpWebResponse 对象调用 webResponse.Close() 和/或 responseStream.Close()。文档表明您可以关闭流或 HttpWebResponse 对象。调用两者都无害，所以我做到了。不关闭响应可能会导致应用程序用尽连接以供重用，据我在代码中观察到，这似乎会影响 HttpWebRequest.GetRequestStream。

Answer 2

我不知道这是否会帮助您解决特定问题，但您应该考虑在完成这些对象后处理它们。我最近正在做类似的事情，并且在 using 语句中包装东西似乎为我清理了一堆超时异常。

            using (var reqStream = request.GetRequestStream())
            {
                if (reqStream == null)
                {
                    return;
                }

              //do whatever

            }

还要检查这些东西

• 服务器是否在您的本地开发环境中提供 https 服务？
• 您是否正确设置了绑定 *.443 (https)？
• 您需要在请求中设置凭据吗？
• 是你的应用池账号访问了https资源还是你的账号被通过了？

• 您是否考虑过使用 WebClient 代替？

  using (WebClient client = new WebClient())
      {               
          using (Stream stream = client.OpenRead("https://server-url-xxxx.com"))
          using (StreamReader reader = new StreamReader(stream))
          {
              MessageBox.Show(reader.ReadToEnd());
          }
      }
  

编辑：

从控制台发出请求。

internal class Program
{
    private static void Main(string[] args)
    {
        new Program().Run();
        Console.ReadLine();
    }

    public void Run()
    {

       var request = (HttpWebRequest)System.Net.WebRequest.Create("https://server-url-xxxx.com");
        request.Method = "POST";
        request.ProtocolVersion = System.Net.HttpVersion.Version10;
        request.ContentType = "application/x-www-form-urlencoded";

        using (var reqStream = request.GetRequestStream())
        {
            using(var response = new StreamReader(reqStream )
            {
              Console.WriteLine(response.ReadToEnd());
            }
        }
    }
}

Answer 3

试试这个：

    WebRequest req = WebRequest.Create("https://server-url-xxxx.com");
    req.Method = "POST";
    string json_value = jsonSerializer.Serialize(data); //Body data
    ServicePointManager.Expect100Continue = false;
    using (var streamWriter = new StreamWriter(req.GetRequestStream()))
    {
        streamWriter.Write(json_value);
        streamWriter.Flush();
        streamWriter.Close();
    }
    HttpWebResponse resp = req.GetResponse() as HttpWebResponse;
    Stream GETResponseStream = resp.GetResponseStream();
    StreamReader sr = new StreamReader(GETResponseStream);
    var response = sr.ReadToEnd(); //Response
    resp.Close(); //Close response
    sr.Close(); //Close StreamReader

并查看 URI：

• 保留字符。通过URI发送保留字符可以带 问题! * ' ( ) ; : @ & = + $ , / ? # [ ]

• URI 长度：不应超过 2000 个字符

Answer 4

我也遇到过这个。我想用控制台应用模拟数百个用户。当只模拟一个用户时，一切都很好。但随着用户的增多，Timeout 异常一直出现。

发生超时是因为默认情况下 ConnectionLimit=2 到 ServicePoint（又名网站）。 非常好的文章阅读：https://venkateshnarayanan.wordpress.com/2013/04/17/httpwebrequest-reuse-of-tcp-connections/

你可以做的是：

1) 在一个 servicePoint 中创建更多 ConnectionGroups，因为 ConnectionLimit 是每个 ConnectionGroups 的。

2) 或者你只是增加连接限制。

查看我的解决方案：

private HttpWebRequest CreateHttpWebRequest<U>(string userSessionID, string method, string fullUrl, U uploadData)
{
    HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(fullUrl);
    req.Method = method; // GET PUT POST DELETE
    req.ConnectionGroupName = userSessionID;  // We make separate connection-groups for each user session. Within a group connections can be reused.
    req.ServicePoint.ConnectionLimit = 10;    // The default value of 2 within a ConnectionGroup caused me always a "Timeout exception" because a user's 1-3 concurrent WebRequests within a second.
    req.ServicePoint.MaxIdleTime = 5 * 1000;  // (5 sec) default was 100000 (100 sec).  Max idle time for a connection within a ConnectionGroup for reuse before closing
    Log("Statistics: The sum of connections of all connectiongroups within the ServicePoint: " + req.ServicePoint.CurrentConnections; // just for statistics

    if (uploadData != null)
    {
        req.ContentType = "application/json";
        SerializeToJson(uploadData, req.GetRequestStream());
    }
    return req;
}

/// <summary>Serializes and writes obj to the requestStream and closes the stream. Uses JSON serialization from System.Runtime.Serialization.</summary>        
public void SerializeToJson(object obj, Stream requestStream)
{
    DataContractJsonSerializer json = new DataContractJsonSerializer(obj.GetType());
    json.WriteObject(requestStream, obj);            
    requestStream.Close();
}

Answer 5

你可能想设置超时属性，在这里查看http://www.codeproject.com/Tips/69637/Setting-timeout-property-for-System-Net-WebClient