c# - 简单 HTTPS 请求中的 System.Net.WebException

Question

我遇到了 C# 和一个简单的 HTTPS 请求的问题...

我想请求这个 URL:https://api.sipgate.com/v1/在网络浏览器中它工作正常，但我的 C# 代码不起作用:(有人知道我做错了什么吗？谢谢!

using System.Net;
using System.IO;

// [...]

WebRequest req = WebRequest.Create("https://api.sipgate.com/v1");
req.ContentType = "application/json";

try {
    WebResponse res = req.GetResponse();  // Exception here...
    Stream content = res.GetResponseStream();
    Console.WriteLine((new StreamReader(content)).ReadToEnd());
} catch (Exception e) {
    Console.WriteLine(e.ToString());                
}

异常(exception)情况:

System.Net.WebException: Die zugrunde liegende Verbindung wurde geschlossen: Unerwarteter Fehler beim Senden.. ---> System.IO.IOException: Fehler bei Authentifizierung, da die Gegenseite den Transportstream geschlossen hat.
   bei System.Net.Security.SslState.StartReadFrame(Byte[] buffer, Int32 readBytes, AsyncProtocolRequest asyncRequest)
   bei System.Net.Security.SslState.StartReceiveBlob(Byte[] buffer, AsyncProtocolRequest asyncRequest)
   bei System.Net.Security.SslState.ForceAuthentication(Boolean receiveFirst, Byte[] buffer, AsyncProtocolRequest asyncRequest)
   bei System.Net.Security.SslState.ProcessAuthentication(LazyAsyncResult lazyResult)
   bei System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
   bei System.Net.TlsStream.ProcessAuthentication(LazyAsyncResult result)
   bei System.Net.TlsStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   bei System.Net.PooledStream.Write(Byte[] buffer, Int32 offset, Int32 size)
   bei System.Net.ConnectStream.WriteHeaders(Boolean async)
   --- Ende der internen Ausnahmestapelüberwachung ---
   bei System.Net.HttpWebRequest.GetResponse()
   bei Sipgate_Test.Program.Main(String[] args) in c:\users\abc\documents\visual studio 2017\Projects\def\hij\Program.cs:Zeile 24.

系统.Net.WebException:

Error in authentication because the other side has closed the transport stream.

Answer 1

您缺少对 SSL 的支持。

ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls12;

using (WebClient Client = new WebClient())
    string Content = Client.DownloadString("https://api.sipgate.com/v1");

编辑:感谢@Crowcoder 指出这一点。在生产环境中，您永远不应接受未经验证的任何证书。 ServerCertificateValidationCallback 提供了一种访问您通常无法访问的 SSL 证书信息的方法。例如，参数 error 为您提供特定的证书错误，如名称不匹配。参数 chain 为您提供服务器发送的确切证书链，当系统存储缺少中间 CA 证书时，可用于构建证书链。

ServicePointManager.ServerCertificateValidationCallback += 
    (s, cert, chain, error) =>
{
    return error == SslPolicyErrors.None;
};