“请求已中止：无法创建SSL / TLS安全通道”第一次访问API时

Question

我试图从Web API使用客户端的Web服务，下面是我们目前用来绕过SSL证书的代码

ServicePointManager.ServerCertificateValidationCallback + =（sender，cert，chain，sslPolicyErrors）=> true;

它工作正常，直到他们从最后禁用TLS 1.0和TLS 1.1。现在我们添加了以下代码，以便将TLS 1.2用于客户端服务器连接

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12; ServicePointManager.ServerCertificateValidationCallback + =（sender，cert，chain，sslPolicyErrors）=> true;

现在我收到“请求被中止：无法创建SSL / TLS安全通道。”仅当我第一次点击API时出错，然后在我不断点击API时获得结果，如果我等待一段时间，如果一分钟左右，再次第一次出现相同的错误。

Answer 1

以下代码可用于帮助解决问题。

ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
ServicePointManager.ServerCertificateValidationCallback += ValidateServerCertificate;

...

private static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
    // If the certificate is a valid, signed certificate, return true to short circuit any add'l processing.
    if (sslPolicyErrors == SslPolicyErrors.None)
    {
        return true;
    }
    else
    {
        // cast cert as v2 in order to expose thumbprint prop - if needed
        var requestCertificate = (X509Certificate2)certificate;

        // init string builder for creating a long log entry
        var logEntry = new StringBuilder();

        // capture initial info for the log entry
        logEntry.AppendFormat("SSL Policy Error(s): {0} - Cert Issuer: {1} - SubjectName: {2}",
           sslPolicyErrors.ToString(),
           requestCertificate.Issuer,
           requestCertificate.SubjectName.Name);

        // check for other error types as needed
        if (sslPolicyErrors == SslPolicyErrors.RemoteCertificateChainErrors) //Root CA problem
        {
            // check chain status and log
            if (chain != null && chain.ChainStatus != null)
            {
                // check errors in chain and add to log entry
                foreach (var chainStatus in chain.ChainStatus)
                {
                    logEntry.AppendFormat("|Chain Status: {0} - {1}", chainStatus.Status.ToString(), chainStatus.StatusInformation.Trim());
                }
            }
        }

        // replace with your logger
        MyLogger.Info(logEntry.ToString().Trim());
    }

    return false;
}