Question

我使用此方法执行POST请求：

public static string GetHttp(string url, Dictionary<string, string> query)
    {
        HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
        NameValueCollection outgoingQueryString = HttpUtility.ParseQueryString(String.Empty);
        foreach(var e in query)
        {
            outgoingQueryString.Add(e.Key, e.Value);
        }

        string postData = outgoingQueryString.ToString();
        request.Method = "POST";
        var data = Encoding.ASCII.GetBytes(postData);
        request.ContentType = "application/x-www-form-urlencoded";
        request.ContentLength = data.Length;

        var sp = request.ServicePoint;
        var prop = sp.GetType().GetProperty("HttpBehaviour", BindingFlags.Instance | BindingFlags.NonPublic);
        prop.SetValue(sp, (byte)0, null);
        using (var stream = request.GetRequestStream())
        {
            stream.Write(data, 0, data.Length);
        }

        var response = (HttpWebResponse)request.GetResponse();

        var responseString = new System.IO.StreamReader(response.GetResponseStream()).ReadToEnd();
        return Encoding.ASCII.GetString(
        Encoding.Convert(
            Encoding.UTF8,
            Encoding.GetEncoding(
                Encoding.ASCII.EncodingName,
                new EncoderReplacementFallback(string.Empty),
                new DecoderExceptionFallback()
                ),
            Encoding.UTF8.GetBytes(responseString)
        ));
    }
}

此代码几乎在所有网址上都能正常工作，但在某些网站上，只有在azure上，有时我会收到超时错误。如果请求是通过WebClient而不是HttpWebRequest执行的，我会收到此错误：

[SocketException（0x274c）：连接尝试失败，因为连接方在一段时间后没有正确响应，或者建立的连接失败，因为连接的主机无法响应xx.xx.xxx.xxx:80]      System.Net.Sockets.Socket.DoConnect（EndPoint endPointSnapshot，SocketAddress socketAddress）+395      System.Net.ServicePoint.ConnectSocketInternal（Boolean connectFailure，Socket s4，Socket s6，Socket＆amp; socket，IPAddress＆amp; address，ConnectSocketState state，IAsyncResult asyncResult，Exception＆amp; exception）+515

[WebException：无法连接到远程服务器]      System.Net.HttpWebRequest.GetRequestStream（TransportContext＆amp; context）+58935447

我尝试配置保持连接但这并不能解决问题：

            request.KeepAlive = true;
        request.ProtocolVersion = HttpVersion.Version11;
        request.ServicePoint.ConnectionLimit = 12;
        request.Proxy = null;
        request.Timeout = 240000;
        request.AllowAutoRedirect = false;
        request.Credentials = CredentialCache.DefaultCredentials;
        request.Accept = "*/*";
        ServicePointManager.SetTcpKeepAlive(true, 240000, 240000);
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
        ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

httpwebrequest在azure上失败

0 个答案: