c# - HttpWebRequest - 出现 "Underlying connection was closed"错误

Question

我与这个问题斗争了 2 天，我真的受够了。我发现没有任何效果。

检查这个简单的示例代码:

HttpWebRequest fileReq = (HttpWebRequest)HttpWebRequest.Create(updateInfoFileUrl);
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; //768 for TLS 1.1 and 3072 for TLS 1.2
ServicePointManager.ServerCertificateValidationCallback = delegate
{
    return true;
};
fileReq.KeepAlive = false;

WebProxy proxy = new WebProxy();
proxy.BypassProxyOnLocal = false;
proxy.UseDefaultCredentials = true;
proxy.Credentials = CredentialCache.DefaultCredentials;
fileReq.Proxy = proxy;

HttpWebResponse fileResp = (HttpWebResponse)fileReq.GetResponse();
Stream stream = fileResp.GetResponseStream();

我尝试了 SecurityProtocols 的不同组合。只使用一个，使用所有这些......没有任何效果。我尝试了 HttpWebRequest、HttpClient 甚至 XmlDocument.Load。什么都不管用。我每次都遇到错误。

它有什么问题？

这是我想阅读的文档: https://www.example.com/info.xml

浏览器显示它。甚至 PostMan 也会显示它。

Answer 1

做了一些调试。这不是您的代码的问题，但服务器需要用户代理设置。作品:

HttpWebRequest fileReq = (HttpWebRequest)WebRequest.Create(@"https://www.example.com/info.xml");
fileReq.UserAgent = "sadsad";
fileReq.Method = "GET";

HttpWebResponse fileResp = (HttpWebResponse)fileReq.GetResponse();
Stream stream = fileResp.GetResponseStream();

失败:

HttpWebRequest fileReq = (HttpWebRequest)WebRequest.Create(@"https://www.example.com/info.xml");

//     fileReq.UserAgent = "sadsad";
fileReq.Method = "GET";

HttpWebResponse fileResp = (HttpWebResponse)fileReq.GetResponse();
Stream stream = fileResp.GetResponseStream();