如果可能的话，在 C# 中使用 FtpWebRequest 实现无需第三方 dll 的 FTP/SFTP

我试图通过 C# 中的 FtpWebRequest 类实现 ftp/sftp 但到目前为止还没有成功。

我不想使用任何第三方免费或付费 dll。

凭证就像

1. 主机名 = sftp.xyz.com
2. 用户 ID = abc
3. 密码=123

我能够使用 IP 地址实现 ftp，但无法使用凭据实现上述主机名的 sftp。

对于 sftp，我已将 FtpWebRequest 类的 EnableSsl 属性启用为 true，但出现无法连接到远程服务器的错误。

我可以使用相同的凭据和主机名连接 Filezilla，但不能通过代码连接。

我观察了 filezilla，它将主机名从 sftp.xyz.com 更改为 sftp://sftp.xyz.com 在文本框和命令行中，它将用户 ID 更改为[电子邮件受保护] /cdn-cgi/l/email-protection

我在代码中做了同样的事情，但 sftp 没有成功。

请在这方面需要紧急帮助。提前致谢。

下面是我到目前为止的代码：

private static void ProcessSFTPFile()
{
    try
    {
        string[] fileList = null;
        StringBuilder result = new StringBuilder();

        string uri = "ftp://sftp.xyz.com";

        FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(new Uri(uri));
        ftpRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
        ftpRequest.EnableSsl = true;
        ftpRequest.Credentials = new NetworkCredential("[email protected] /cdn-cgi/l/email-protection", "123");
        ftpRequest.UsePassive = true;
        ftpRequest.Timeout = System.Threading.Timeout.Infinite;

        //ftpRequest.AuthenticationLevel = Security.AuthenticationLevel.MutualAuthRequested;
        //ftpRequest.Proxy = null;
        ftpRequest.KeepAlive = true;
        ftpRequest.UseBinary = true;

        //Hook a callback to verify the remote certificate 
        ServicePointManager.ServerCertificateValidationCallback = new RemoteCertificateValidationCallback(ValidateServerCertificate);
        //ServicePointManager.ServerCertificateValidationCallback = ((sender, certificate, chain, sslPolicyErrors) => true);

        FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
        StreamReader reader = new StreamReader(response.GetResponseStream());
        string line = reader.ReadLine();
        while (line != null)
        {
            result.Append("ftp://sftp.xyz.com" + line);
            result.Append("\n");
            line = reader.ReadLine();
        }

        if (result.Length != 0)
        {
            // to remove the trailing '\n'
            result.Remove(result.ToString().LastIndexOf('\n'), 1);

            // extracting the array of all ftp file paths
            fileList = result.ToString().Split('\n');
        }

    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message.ToString());
        Console.ReadLine();
    }
}

public static bool ValidateServerCertificate(object sender, X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
    if (certificate.Subject.Contains("CN=sftp.xyz.com"))
    {
        return true;
    }
    else
    {
        return false;
    }
}

UPDATE:

如果使用BizTalk，您可以使用 SFTP 适配器 https://social.technet.microsoft.com/wiki/contents/articles/19781.biztalk-server-2013-how-to-use-sftp-adapter.aspx， 使用ESB 工具包 https://msdn.microsoft.com/en-us/biztalk/biztalk-esbtoolkit.aspx。它自 2010 年以来一直受到支持。人们想知道为什么它没有进入.Net Framework

1. BizTalk Server 2013：以 ESB 工具包 SFTP 中创建自定义适配器提供程序为例 https://social.technet.microsoft.com/wiki/contents/articles/22035.biztalk-server-2013-creating-custom-adapter-provider-in-esb-toolkit-sftp-as-an-example.aspx
2. BizTalk Server 2013：如何使用 SFTP 适配器 https://social.technet.microsoft.com/wiki/contents/articles/22035.biztalk-server-2013-creating-custom-adapter-provider-in-esb-toolkit-sftp-as-an-example.aspx
3. MSDN 文档 https://learn.microsoft.com/en-us/previous-versions/azure/dn232420(v=azure.100)

--

不幸的是，目前仅框架仍需要大量工作。放置sftp协议前缀不足以make-it-work今天仍然没有内置的 .Net Framework 支持，也许将来也没有。

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1）一个值得尝试的好库是SSHNet https://github.com/sshnet/SSH.NET.

-------------------------------------------------- --------

It has:

1. 更多功能，包括内置流媒体支持。
2. API 文档
3. 更简单的 API 来进行编码

文档中的示例代码：

列出目录

/// <summary>
/// This sample will list the contents of the current directory.
/// </summary>
public void ListDirectory()
{
    string host            = "";
    string username        = "";
    string password        = "";
    string remoteDirectory = "."; // . always refers to the current directory.
    
    using (var sftp = new SftpClient(host, username, password))
    {
        sftp.Connect();

        var files = sftp.ListDirectory(remoteDirectory);
        foreach (var file in files)
        {
            Console.WriteLine(file.FullName);
        }
    }
}

上传文件

/// <summary>
/// This sample will upload a file on your local machine to the remote system.
/// </summary>
public void UploadFile()
{
    string host           = "";
    string username       = "";
    string password       = "";
    string localFileName  = "";
    string remoteFileName = System.IO.Path.GetFileName(localFile);

    using (var sftp = new SftpClient(host, username, password))
    {
        sftp.Connect();

        using (var file = File.OpenRead(localFileName))
        {
            sftp.UploadFile(remoteFileName, file);
        }

        sftp.Disconnect();
    }
}

下载文件

/// <summary>
/// This sample will download a file on the remote system to your local machine.
/// </summary>
public void DownloadFile()
{
    string host           = "";
    string username       = "";
    string password       = "";
    string localFileName  = System.IO.Path.GetFileName(localFile);
    string remoteFileName = "";

    using (var sftp = new SftpClient(host, username, password))
    {
        sftp.Connect();

        using (var file = File.OpenWrite(localFileName))
        {
            sftp.DownloadFile(remoteFileName, file);
        }

        sftp.Disconnect();
    }
}

-------------------------------------------------- --------

2）另一个替代库是WinSCP https://winscp.net/eng/docs/library

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用下面的例子：

using System;
using WinSCP;
 
class Example
{
    public static int Main()
    {
        try
        {
            // Setup session options
            SessionOptions sessionOptions = new SessionOptions
            {
                Protocol = Protocol.Sftp,
                HostName = "example.com",
                UserName = "user",
                Password = "mypassword",
                SshHostKeyFingerprint = "ssh-rsa 2048 xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx:xx"
            };
 
            using (Session session = new Session())
            {
                // Connect
                session.Open(sessionOptions);
 
                // Upload files
                TransferOptions transferOptions = new TransferOptions();
                transferOptions.TransferMode = TransferMode.Binary;
 
                TransferOperationResult transferResult;
                transferResult = session.PutFiles(@"d:\toupload\*", "/home/user/", false, transferOptions);
 
                // Throw on any error
                transferResult.Check();
 
                // Print results
                foreach (TransferEventArgs transfer in transferResult.Transfers)
                {
                    Console.WriteLine("Upload of {0} succeeded", transfer.FileName);
                }
            }
 
            return 0;
        }
        catch (Exception e)
        {
            Console.WriteLine("Error: {0}", e);
            return 1;
        }
    }
}

在这里找到 https://winscp.net/eng/docs/library#csharp与更多这里 https://winscp.net/eng/docs/library_examples.