Best option for file transfer using VB.Net

Question

Hi

I am in a need to develop VB.Net application with file transfer support from source computer to remote computer.
What would be reliable option here, FTP, SSH (if supported), any example or suggestion(s)?

Answer 1

Depends upon what you mean by "remote computer". On the same network then use standard File operations and UNC paths. This assumes the user has permissions to both servers. If you need more complex logic then simple file operations then you can also call out to a tool like robocopy.

If you need to transfer files to a machine across the Internet then that is what (S)FTP is for. .NET Framework supports FTP but .NET Core/6 no longer do. You'll need to use a third party library.

However FTP is archaic and annoying to work with. There are quite a few file transfer services available online now that have APIs to allow you to better integrate this kind of functionality. However you'll want to look for services that allow you to control what happens when you get files and not just file sharing services as they aren't sufficient here.

Answer 2

You can use WinSCP

A test with a random public SFTP server :

 Try  
            Dim sessionOptions As New SessionOptions  
            With sessionOptions  
                .Protocol = Protocol.Sftp  
                .HostName = "test.rebex.net"  
                .UserName = "demo"  
                .Password = "password"  
                ' From WinSCP client  
                .SshHostKeyFingerprint = "ssh-rsa 2048 03:61:c4:98:f1:ff:7d:23:97:51:07:13:88:b8:c5:55"  
            End With  
  
            Using session As New Session  
                session.Open(sessionOptions)  
                Dim directory As RemoteDirectoryInfo = session.ListDirectory("/pub/example")  
                Dim fileInfo As RemoteFileInfo  
                For Each fileInfo In directory.Files  
                    Console.WriteLine(  
                        "{0} with size {1}, permissions {2} and last modification at {3}",  
                        fileInfo.Name, fileInfo.Length, fileInfo.FilePermissions,  
                        fileInfo.LastWriteTime)  
                Next  
            End Using  
        Catch ex As Exception  
            Console.WriteLine("Error: {0}", ex)  
        End Try  

Answer 3

This is a complete function. Remember to get fingerprint key or use "GiveUpSecurityAndAcceptAny" for public key of secure servers.

'open files
        OpenFileDialog1.FileName = ""
        OpenFileDialog1.Title = "Scegli i files da trasferire in SFTP"
        OpenFileDialog1.Filter = "Tutti i files|*.*"
        If OpenFileDialog1.ShowDialog() = DialogResult.OK Then
            For Each file In OpenFileDialog1.FileNames
                RichTextBox2.Text &= file & vbCrLf
            Next
        End If

'INVIA
        Try
            Dim sessionOptions As New SessionOptions
            With sessionOptions
                .Protocol = Protocol.Sftp
                .HostName = "test.rebex.net" 'port 22
                .UserName = "demo"
                .Password = "password"
                '.SshHostKeyFingerprint = "BNE4ZvsKbhnbnnU9Vd/fgHhpW4+180012oSylyeNJYs"
                '.SshHostKeyFingerprint = TextBox1.Text
                '.GiveUpSecurityAndAcceptAnySshHostKey = True
                .SshHostKeyPolicy = SshHostKeyPolicy.GiveUpSecurityAndAcceptAny
            End With

            Using session As New Session
                'connessione
                session.Open(sessionOptions)

                'Upload Files
                Dim transferOptions As New TransferOptions
                transferOptions.TransferMode = TransferMode.Binary

                Dim lista As String()
                lista = Split(RichTextBox2.Text, vbCrLf)

                For Each file In lista
                    Dim transferResult As TransferOperationResult
                    'remote folder /home/user/
                    transferResult = session.PutFiles(file, "/home/user/", False, transferOptions)

                    'vai avanti su errore
                    transferResult.Check()

                    'Stampa
                    For Each transfer In transferResult.Transfers
                        RichTextBox1.Text = ("Trasferimenti di " & transfer.FileName & " eseguito.")
                    Next
                Next

            End Using

        Catch ex As Exception

        End Try