Lianja

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. Lianja

llSuccess = .F.

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

loTunnel = createobject("CkSocket")

lcSshHostname = "sftp.example.com"
lnSshPort = 22

// Connect to an SSH server and establish the SSH tunnel:
llSuccess = loTunnel.SshOpenTunnel(lcSshHostname,lnSshPort)
if (llSuccess = .F.) then
    ? loTunnel.LastErrorText
    release loTunnel
    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.
llSuccess = loTunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
if (llSuccess = .F.) then
    ? loTunnel.LastErrorText
    release loTunnel
    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.

loImap = createobject("CkImap")

// Let the IMAP object also use the SSH tunnel
llSuccess = loImap.UseSshTunnel(loTunnel)
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    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.
loImap.Ssl = .T.
loImap.Port = 993
llSuccess = loImap.Connect("imap.my-imap-server.com")
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    return
endif

// Authenticate with the IMAP server via the SSH tunnel.
llSuccess = loImap.Login("myLogin","myPassword")
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    return
endif

// Select an IMAP mailbox
llSuccess = loImap.SelectMailbox("Inbox")
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    return
endif

// How many messages in Inbox?
lnMsgCount = loImap.NumMessages
if (lnMsgCount = 0) then
    ? "No messages found."
    release loTunnel
    release loImap
    return
endif

lnUpperBound = 10
if (lnMsgCount < lnUpperBound) then
    lnUpperBound = lnMsgCount
endif

// Download up to the 1st 10 messages.
loEmail = createobject("CkEmail")

llBUid = .F.
for i = 1 to lnUpperBound

    llSuccess = loImap.FetchEmail(.F.,i,llBUid,loEmail)
    if (llSuccess = .F.) then
        ? loImap.LastErrorText
        release loTunnel
        release loImap
        release loEmail
        return
    endif

    ? loEmail.From
    ? loEmail.Subject

next

// Disconnect from the IMAP server.
// The SSH tunnel remains open.
llSuccess = loImap.Disconnect()
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    release loEmail
    return
endif

// It is possible to re-use the existing SSH tunnel for the next connection:
llSuccess = loImap.Connect("imap.my-imap-server2.com")
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    release loEmail
    return
endif

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

// This closes the SSH channel, which is the connection with the IMAP server.
// It does not close the SSH tunnel
llSuccess = loImap.Disconnect()
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    release loEmail
    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.
llSuccess = loImap.SshCloseTunnel()
if (llSuccess = .F.) then
    ? loImap.LastErrorText
    release loTunnel
    release loImap
    release loEmail
    return
endif

// This actually closes the SSH tunnel because it's the last object using it.
llSuccess = loTunnel.SshCloseTunnel()
if (llSuccess = .F.) then
    ? loTunnel.LastErrorText
    release loTunnel
    release loImap
    release loEmail
    return
endif

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


release loTunnel
release loImap
release loEmail