C# 从 HTTPS URL 中获取服务器证书抛出 System.PlatformNotSupportedException 异常

Question

我使用以下代码片段从 C# 中的 HTTPS URL 网站获取(或获取)证书。

此处发布了类似的代码 -> Open Certificate Information from Web Browser Control和 C# Download all https certificates from a website 但没有任何帮助，我在下面的行 #

中不断收到异常

           X509Certificate cert = request.ServicePoint.Certificate;

异常:

   System.PlatformNotSupportedException: 'Operation is not supported on this platform.'

代码:

 private static void Main(string[] args)
    {
        String sslServerHost = "https://docs.genesys.com/Documentation"
        HttpWebRequest request = (HttpWebRequest) WebRequest.Create( sslServerHost);
        request.AllowAutoRedirect = false;

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


       X509Certificate cert = request.ServicePoint.Certificate;

        //convert the X509Certificate to an X509Certificate2 object by passing it into the constructor
       X509Certificate2 cert2 = new X509Certificate2(cert);

        X509Store userCaStore = new X509Store(storeName: StoreName.Root, storeLocation: StoreLocation.CurrentUser);
        try
        {
            userCaStore.Open(OpenFlags.ReadOnly);
            userCaStore.Add(cert2);

            Stream dataStream = response.GetResponseStream();
            StreamReader reader = new StreamReader(dataStream);
            string responseFromServer = reader.ReadToEnd();
            Debug.WriteLine(responseFromServer);
            Console.WriteLine(responseFromServer);

        } catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }

    }

更新

.NET Core 项目不支持 ServicePoint.Certificate，因此我尝试使用以下代码使用服务器证书验证回调:

request.ServerCertificateValidationCallback += (sender, validatedCert, chain, 
errors) => { X509Certificate cert = new X509Certificate2(validatedCert); 
Console.WriteLine("Inside callback" + cert); return errors == 
System.Net.Security.SslPolicyErrors.None; }

上面的回调似乎没有被调用。你们中的任何人都可以告诉我们什么时候执行上述回调。

此外，在未将服务器证书添加到信任库的情况下尝试连接到 HTTPS URL 时，我没有遇到任何异常。谁能告诉我为什么在尝试访问 HTTPS URL 时我们没有收到任何异常(在 .NET 应用程序中)，因为我没有忽略证书验证。

Answer 1

在 .Net 核心上使用遗留的 HttpWebRequest 是自找麻烦。您应该切换到 HttpClient 并设置 callback在 HttpClientHandler 实例上。

  var handler = new HttpClientHandler();
  handler.ServerCertificateCustomValidationCallback = (request,cert,chain,error) => true;
  var client = new HttpClient(handler);