Xbase++ Requires Chilkat v11.0.0+

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. Xbase++

LOCAL nSuccess
LOCAL oTunnel
LOCAL cSshHostname
LOCAL nSshPort
LOCAL oImap
LOCAL nMsgCount
LOCAL nUpperBound
LOCAL oEmail
LOCAL i
LOCAL nBUid

nSuccess := 0

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

oTunnel := CreateObject("Chilkat.Socket")

cSshHostname := "sftp.example.com"
nSshPort := 22

//  Connect to an SSH server and establish the SSH tunnel:
nSuccess := oTunnel:SshOpenTunnel(cSshHostname, nSshPort)
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//  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.
nSuccess := oTunnel:SshAuthenticatePw("mySshLogin", "mySshPassword")
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//  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.

oImap := CreateObject("Chilkat.Imap")

//  Let the IMAP object also use the SSH tunnel
nSuccess := oImap:UseSshTunnel(oTunnel)
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    RETURN
ENDIF

//  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.
oImap:Ssl := 1
oImap:Port := 993
nSuccess := oImap:Connect("imap.my-imap-server.com")
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    RETURN
ENDIF

//  Authenticate with the IMAP server via the SSH tunnel.
nSuccess := oImap:Login("myLogin", "myPassword")
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    RETURN
ENDIF

//  Select an IMAP mailbox
nSuccess := oImap:SelectMailbox("Inbox")
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    RETURN
ENDIF

//  How many messages in Inbox?
nMsgCount := oImap:NumMessages
IF (nMsgCount == 0)
    ? "No messages found."
    oTunnel:destroy()
    oImap:destroy()
    RETURN
ENDIF

nUpperBound := 10
IF (nMsgCount < nUpperBound)
    nUpperBound := nMsgCount
ENDIF

//  Download up to the 1st 10 messages.
oEmail := CreateObject("Chilkat.Email")

nBUid := 0
FOR i := 1 TO nUpperBound

    nSuccess := oImap:FetchEmail(0, i, nBUid, oEmail)
    IF (nSuccess == 0)
        ? oImap:LastErrorText
        oTunnel:destroy()
        oImap:destroy()
        oEmail:destroy()
        RETURN
    ENDIF

    ? oEmail:From
    ? oEmail:Subject

NEXT

//  Disconnect from the IMAP server.
//  The SSH tunnel remains open.
nSuccess := oImap:Disconnect()
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    oEmail:destroy()
    RETURN
ENDIF

//  It is possible to re-use the existing SSH tunnel for the next connection:
nSuccess := oImap:Connect("imap.my-imap-server2.com")
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    oEmail:destroy()
    RETURN
ENDIF

//  Review the LastErrorText to see that the connection was made via the SSH tunnel:
? oImap:LastErrorText

//  This closes the SSH channel, which is the connection with the IMAP server.
//  It does not close the SSH tunnel
nSuccess := oImap:Disconnect()
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    oEmail:destroy()
    RETURN
ENDIF

//  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.
nSuccess := oImap:SshCloseTunnel()
IF (nSuccess == 0)
    ? oImap:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    oEmail:destroy()
    RETURN
ENDIF

//  This actually closes the SSH tunnel because it's the last object using it.
nSuccess := oTunnel:SshCloseTunnel()
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    oImap:destroy()
    oEmail:destroy()
    RETURN
ENDIF

? "IMAP pre-existing SSH tunnel example completed."

oTunnel:destroy()
oImap:destroy()
oEmail:destroy()