c# - 使用 SSL 的网络请求

Question

我有以下代码可以使用 FTP 检索文件(效果很好)。

            FtpWebRequest request = (FtpWebRequest)WebRequest.Create(svrPath);

            request.KeepAlive = true;
            request.UsePassive = true;
            request.UseBinary = true;

            request.Method = WebRequestMethods.Ftp.DownloadFile;
            request.Credentials = new NetworkCredential(uname, passw);

            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            using (Stream responseStream = response.GetResponseStream())
            using (StreamReader reader = new StreamReader(responseStream))
            using (StreamWriter destination = new StreamWriter(destinationFile))
            {
                destination.Write(reader.ReadToEnd());
                destination.Flush();
            }

但是，当我尝试使用 SSL 执行此操作时，我无法访问该文件，如下所示:

            FtpWebRequest request = (FtpWebRequest)WebRequest.Create(svrPath);

            request.KeepAlive = true;
            request.UsePassive = true;
            request.UseBinary = true;

            // The following line causes the download to fail
            request.EnableSsl = true;

            request.Method = WebRequestMethods.Ftp.DownloadFile;
            request.Credentials = new NetworkCredential(uname, passw);

            using (FtpWebResponse response = (FtpWebResponse)request.GetResponse())
            using (Stream responseStream = response.GetResponseStream())
            using (StreamReader reader = new StreamReader(responseStream))
            using (StreamWriter destination = new StreamWriter(destinationFile))
            {
                destination.Write(reader.ReadToEnd());
                destination.Flush();
            }

谁能告诉我为什么后者不起作用？

编辑:

我得到以下异常:

The remote server returned an error: (530) Not logged in.

Answer 1

您在哪里验证 SSL 证书？通过 FTP 连接执行 SSL 并不像设置 .EnableSsl 属性那么简单。您需要提供证书验证方法。参见 this article让 C# 代码做你想做的事。此外，有人在 this MSDN article 中复制并粘贴了他们的整个 FTP 类。如果您需要更详细的实现。

只是为了让你快速启动并快速运行，用这个测试:

if (request.EnableSsl) ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(ValidateServerCertificate);

然后是:

public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors) {
 return true; // Read the links provided above for real implementation
}