Achieving FTP/SFTP without 3rd party dll with FtpWebRequest if possible in C#

.net, c#, winforms

Solution

UPDATE:

If using BizTalk, you can work with the SFTP Adapter, using the ESB Toolkit. It has been supported since 2010. One wonders why it didn't make it to the `.Net Framework`

- BizTalk Server 2013: Creating Custom Adapter Provider in ESB Toolkit SFTP As an Example

- BizTalk Server 2013: How to use SFTP Adapter

- MSDN Docs

--

Unfortunately, it still requires alot of work to do with just the Framework currently. Placing the `sftp` protocol prefix isnt enough to `make-it-work` Still no built-in, .Net Framework support today, maybe in the future.

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

1) A good library to try out is SSHNet.

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

It has:

- a lot more features, including built-in streaming support.

- an API document

- a simpler API to code against

Example code from documentation:

List directory

/// <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);
        }
    }
}

Upload File

/// <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();
    }
}

Download File

/// <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) Another alternative library is WinSCP

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

With the follwing example:

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;
        }
    }
}

Found here and with more here.

Problem

Original source