B4X

FTP through SSH Tunnel

See more FTP Examples

Demonstrates how to FTP through an SSH tunnel.

The Chilkat SSH tunnel object is used to create a portable SSH tunnel w/ dynamic port forwarding on a background thread that the foreground thread can use for establishing connections through an SSH tunnel.

B4X

Dim success As Boolean = False

'  This example assumes the Chilkat API to have been previously unlocked.
'  See Global Unlock Sample for sample code.

success = False

Dim tunnel As ChilkatSshTunnel
tunnel.Initialize("tunnel")

Dim sshHostname As String = "sftp.example.com"
Dim sshPort As Int = 22

'  Connect to an SSH server and establish the SSH tunnel:
success = tunnel.Connect(sshHostname, sshPort)
If success <> True Then
    Log(tunnel.LastErrorText)
    Return
End If


'  Authenticate with the SSH server via a login/password
'  or with a public key.  
'  This example demonstrates SSH password authentication.
success = tunnel.AuthenticatePw("mySshLogin", "mySshPassword")
If success <> True Then
    Log(tunnel.LastErrorText)
    Return
End If


'  Indicate that the background SSH tunnel thread will behave as a SOCKS proxy server
'  with dynamic port forwarding:
tunnel.DynamicPortForwarding = True

'  We may optionally require that connecting clients authenticate with our SOCKS proxy server.
'  To do this, set an inbound username/password.  Any connecting clients would be required to 
'  use SOCKS5 with the correct username/password.
'  If no inbound username/password is set, then our SOCKS proxy server will accept both
'  SOCKS4 and SOCKS5 unauthenticated connections.

tunnel.InboundSocksUsername = "chilkat123"
tunnel.InboundSocksPassword = "password123"

'  Start the listen/accept thread to begin accepting SOCKS proxy client connections.
'  Listen on port 1080.
success = tunnel.BeginAccepting(1080)
If success <> True Then
    Log(tunnel.LastErrorText)
    Return
End If


'  Now that a background thread is running a SOCKS proxy server that forwards connections
'  through an SSH tunnel, it is possible to use any Chilkat implemented protocol that is SOCKS capable,
'  such as Socket, HTTP, POP3, SMTP, IMAP, FTP, etc.  The protocol may use SSL/TLS because the SSL/TLS
'  will be passed through the SSH tunnel to the end-destination.  Also, any number of simultaneous
'  connections may be routed through the SSH tunnel.

'  Let's do an FTP upload through the SSH tunnel.  Both the control and data connections 
'  go through the tunnel.
Dim ftp As ChilkatFtp2
ftp.Initialize("ftp")

ftp.Hostname = "ftp.example.com"
ftp.Username = "login"
ftp.Password = "password"

'  Indicate that the FTP2 object is to use our portable SOCKS proxy/SSH tunnel running in our background thread.
ftp.SocksHostname = "localhost"
ftp.SocksPort = 1080
ftp.SocksVersion = 5
ftp.SocksUsername = "chilkat123"
ftp.SocksPassword = "password123"

'  Connect to the FTP server
success = ftp.ConnectOnly
If success <> True Then
    Log(ftp.LastErrorText)
    Return
End If


'  Authenticate with the FTP server.
success = ftp.LoginAfterConnectOnly
If success <> True Then
    Log(ftp.LastErrorText)
    Return
End If


'  Change to the remote directory where the file will be uploaded.
success = ftp.ChangeRemoteDir("junk")
If success <> True Then
    Log(ftp.LastErrorText)
    Return
End If


'  Upload a file.
Dim localPath As String = "/temp/hamlet.xml"
Dim remoteFilename As String = "hamlet.xml"

success = ftp.PutFile(localPath, remoteFilename)
If success <> True Then
    Log(ftp.LastErrorText)
    Return
End If


'  This closes the SSH channel within the SSH tunnel,
'  and thus closes the connection with the FTP server.
success = ftp.Disconnect

Log("File Uploaded!")

'  Stop the background listen/accept thread:
Dim waitForThreadExit As Boolean = True
success = tunnel.StopAccepting(waitForThreadExit)
If success <> True Then
    Log(tunnel.LastErrorText)
    Return
End If


'  Close the SSH tunnel (would also kick any remaining connected clients).
success = tunnel.CloseTunnel(waitForThreadExit)
If success <> True Then
    Log(tunnel.LastErrorText)
    Return
End If