Question

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

API在服务器上具有普通HTTP和安全层（HTTPS）PORT。当我调用HTTP URL时，它工作得非常好。但是，当我调用HTTPS时，它会给我超时异常（在GetRequestStream（）函数中）。任何见解？我正在使用VS 2010，.Net framework 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：彼得建议的控制台程序运行正常。但是当我添加需要发布到API的数据（以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，它会抛出错误。

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

Answer 1

我遇到了同样的问题。好像它已经为我解决了。我查看了所有代码，确保为所有HttpWebResponse对象调用 webResponse.Close（）和/或 responseStream.Close（）。该文档表明您可以关闭流或HttpWebResponse对象。调用两者都没有害处，所以我做到了。不关闭响应可能会导致应用程序耗尽连接以便重用，这似乎会影响HttpWebRequest.GetRequestStream，就我在代码中可以看到的那样。

Answer 2

我不知道这是否可以帮助您解决具体问题，但是您应该考虑在完成这些对象后对其进行处理。我最近正在做这样的事情，并且在使用语句中包装东西似乎为我清除了一堆超时异常。

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

              //do whatever

            }

还检查这些事情

服务器是否在本地开发环境中提供https服务？
您是否正确设置了绑定* .443（https）？
您是否需要在请求中设置凭据？
是您的应用程序池帐户访问https资源还是您的帐户正在通过？

您是否考虑过使用WebClient？

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来问题! * ' ( ) ; : @ & = + $ , / ? # [ ]
URI长度：不应超过2000个字符

Answer 4

您可能需要设置超时属性，请在此处查看http://www.codeproject.com/Tips/69637/Setting-timeout-property-for-System-Net-WebClient

Answer 5

我也遇到了这个。我想使用控制台应用程序模拟数百个用户。仅模拟一个用户时，一切都很好。但是随着越来越多的用户出现，超时异常一直存在。

发生超时是因为默认情况下，ServiceLimit（即网站）的ConnectionLimit = 2。很棒的文章：https://venkateshnarayanan.wordpress.com/2013/04/17/httpwebrequest-reuse-of-tcp-connections/

您可以做的是：

1）在servicePoint内创建更多ConnectionGroup，因为ConnectionLimit是针对每个ConnectionGroup的。

2）或您只需增加连接限制。

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();
}

将数据发布到HTTPS网址时，GetRequestStream（）会抛出超时异常

5 个答案: