Xojo Plugin

IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding. Xojo Plugin

Dim success As Boolean
success = False

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

Dim tunnel As New Chilkat.Socket

Dim sshHostname As String
sshHostname = "sftp.example.com"
Dim sshPort As Int32
sshPort = 22

// Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort)
If (success = False) Then
    System.DebugLog(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.
// Note: This is not authenticating with the IMAP server, it is
// for authenticating with the SSH server, which is separate.
success = tunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
If (success = False) Then
    System.DebugLog(tunnel.LastErrorText)
    Return
End If

// OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
// Once the channel is obtained, the Socket API may
// be used exactly the same as usual, except all communications
// are sent through the channel in the SSH tunnel.
// Any number of channels may be created from the same SSH tunnel.
// Multiple channels may coexist at the same time.

Dim imap As New Chilkat.Imap

// Let the IMAP object also use the SSH tunnel
success = imap.UseSshTunnel(tunnel)
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Connect to an IMAP server via the already established SSH tunnel.
// Because the SSH tunnel has been previously setup,
// this does not establish a direct connection with the IMAP
// server.  It directs the SSH server to establish the connection.

// In this example, the IMAP server requires SSL/TLS.  The TLS connection
// will be enclosed within the SSH tunnel.
imap.Ssl = True
imap.Port = 993
success = imap.Connect("imap.my-imap-server.com")
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Authenticate with the IMAP server via the SSH tunnel.
success = imap.Login("myLogin","myPassword")
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// How many messages in Inbox?
Dim msgCount As Int32
msgCount = imap.NumMessages
If (msgCount = 0) Then
    System.DebugLog("No messages found.")
    Return
End If

Dim upperBound As Int32
upperBound = 10
If (msgCount < upperBound) Then
    upperBound = msgCount
End If

// Download up to the 1st 10 messages.
Dim email As New Chilkat.Email
Dim i As Int32
Dim bUid As Boolean
bUid = False
For i = 1 To upperBound

    success = imap.FetchEmail(False,i,bUid,email)
    If (success = False) Then
        System.DebugLog(imap.LastErrorText)
        Return
    End If

    System.DebugLog(email.From)
    System.DebugLog(email.Subject)

Next

// Disconnect from the IMAP server.
// The SSH tunnel remains open.
success = imap.Disconnect()
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// It is possible to re-use the existing SSH tunnel for the next connection:
success = imap.Connect("imap.my-imap-server2.com")
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
System.DebugLog(imap.LastErrorText)

// This closes the SSH channel, which is the connection with the IMAP server.
// It does not close the SSH tunnel
success = imap.Disconnect()
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// Finally, close the SSH tunnel.

// Note: If other objects are using the same SSH tunnel, the tunnel is not 
// actually closed.  It is only closed when the last object using the tunnel closes it.

// At this point, both the imap and tunnel objects have references to the internal
// SSH tunnel.  We need to close each.

// This call doesn't actually close the tunnel yet, because the tunnel object still
// holds an internal reference.
success = imap.SshCloseTunnel()
If (success = False) Then
    System.DebugLog(imap.LastErrorText)
    Return
End If

// This actually closes the SSH tunnel because it's the last object using it.
success = tunnel.SshCloseTunnel()
If (success = False) Then
    System.DebugLog(tunnel.LastErrorText)
    Return
End If

System.DebugLog("IMAP pre-existing SSH tunnel example completed.")