B4X Requires Chilkat v11.0.0+

IMAP SSH Tunneling (Port Forwarding)

Demonstrates how to setup and use an SSH tunnel for IMAP. B4X

Dim success As Boolean = False

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

Dim imap As ChilkatImap
imap.Initialize("imap")

'  The SSH hostname may be a hostname or an 
'  IP address, such as "192.168.1.108".
'  The port is typically 22 (the standard port for SSH).
Dim sshHostname As String = "www.mysshserver.com"
Dim sshPort As Int = 22

'  Connect to an SSH server and establish the SSH tunnel:
success = imap.SshOpenTunnel(sshHostname, sshPort)
If success = False Then
    Log(imap.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 = imap.SshAuthenticatePw("mySshLogin", "mySshPassword")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  OK, the SSH tunnel is setup.  The IMAP component may
'  be used exactly the same as usual, except all communications
'  are sent through the SSH tunnel.

'  Connect to an IMAP server via the 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
    Log(imap.LastErrorText)
    Return
End If


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


'  Select an IMAP mailbox
success = imap.SelectMailbox("Inbox")
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  How many messages in Inbox?
Dim msgCount As Int = imap.NumMessages
If msgCount = 0 Then
    Log("No messages found.")
    Return
End If


Dim upperBound As Int = 10
If msgCount < upperBound Then
    upperBound = msgCount
End If


'  Download up to the 1st 10 messages.
Dim email As ChilkatEmail
email.Initialize
Dim i As Int
Dim bUid As Boolean = False
For i = 1 To upperBound


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


    Log(email.From)
    Log(email.Subject)
    Log("----")
Next

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


'  Review the LastErrorText to see that the connection was made via the SSH tunnel:
Log(imap.LastErrorText)

success = imap.Disconnect
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


'  Finally, close the SSH tunnel.
success = imap.SshCloseTunnel
If success = False Then
    Log(imap.LastErrorText)
    Return
End If


Log("IMAP SSH tunneling example completed.")