c# - 在 C# 中使用代理连接到 FTPS

Question

我的以下代码在没有代理的情况下在我的计算机上运行良好。但是在客户端服务器中，他们需要向 FTP 客户端(FileZilla)添加代理才能访问 FTP。但是当我添加代理时，它说

SSL cannot be enabled when using a proxy.

FTP 代理

var proxyAddress = ConfigurationManager.AppSettings["ProxyAddress"];
WebProxy ftpProxy = null;
if (!string.IsNullOrEmpty(proxyAddress))
{
   var proxyUserId = ConfigurationManager.AppSettings["ProxyUserId"];
   var proxyPassword = ConfigurationManager.AppSettings["ProxyPassword"];
    ftpProxy = new WebProxy
    {
        Address = new Uri(proxyAddress, UriKind.RelativeOrAbsolute),
        Credentials = new NetworkCredential(proxyUserId, proxyPassword)
    };
 }

FTP 连接

var ftpRequest = (FtpWebRequest)WebRequest.Create(ftpAddress);
ftpRequest.Credentials = new NetworkCredential(
                            username.Normalize(), 
                            password.Normalize()
                         );

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

ServicePointManager.Expect100Continue = false;

ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
ftpRequest.EnableSsl = true;
//ftpRequest.Proxy = ftpProxy;
var response = (FtpWebResponse)ftpRequest.GetResponse();

Answer 1

.NET 框架确实不支持通过代理的 TLS/SSL 连接。

您必须使用第 3 方 FTP 库。

另请注意，您的代码未使用“隐式”FTPS。它使用“显式”FTPS。 Implicit FTPS is not supported by .NET framework要么。

---

例如 WinSCP .NET assembly ，你可以使用:

// Setup session options
SessionOptions sessionOptions = new SessionOptions
{
    Protocol = Protocol.Ftp,
    HostName = "example.com",
    UserName = "user",
    Password = "mypassword",
    FtpSecure = FtpSecure.Explicit, // Or .Implicit
};

// Configure proxy
sessionOptions.AddRawSettings("ProxyMethod", "3");
sessionOptions.AddRawSettings("ProxyHost", "proxy");

using (Session session = new Session())
{
    // Connect
    session.Open(sessionOptions);

    var listing = session.ListDirectory(path);
}

对于 SessionOptions.AddRawSettings 的选项, 请参阅 raw settings .

(我是 WinSCP 的作者)