(PureBasic) IMAP SSH Tunneling (Port Forwarding)

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

Note: This example requires Chilkat v11.0.0 or greater.

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IncludeFile "CkEmail.pb"
IncludeFile "CkImap.pb"

Procedure ChilkatExample()

    success.i = 0

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

    imap.i = CkImap::ckCreate()
    If imap.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 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).
    sshHostname.s = "www.mysshserver.com"
    sshPort.i = 22

    ; Connect to an SSH server and establish the SSH tunnel:
    success = CkImap::ckSshOpenTunnel(imap,sshHostname,sshPort)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    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.
    success = CkImap::ckSshAuthenticatePw(imap,"mySshLogin","mySshPassword")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; 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.
    CkImap::setCkSsl(imap, 1)
    CkImap::setCkPort(imap, 993)
    success = CkImap::ckConnect(imap,"imap.my-imap-server.com")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; Authenticate with the IMAP server via the SSH tunnel.
    success = CkImap::ckLogin(imap,"myLogin","myPassword")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; Select an IMAP mailbox
    success = CkImap::ckSelectMailbox(imap,"Inbox")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    ; How many messages in Inbox?
    msgCount.i = CkImap::ckNumMessages(imap)
    If msgCount = 0
        Debug "No messages found."
        CkImap::ckDispose(imap)
        ProcedureReturn
    EndIf

    upperBound.i = 10
    If msgCount < upperBound
        upperBound = msgCount
    EndIf

    ; Download up to the 1st 10 messages.
    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    i.i
    bUid.i = 0
    For i = 1 To upperBound

        success = CkImap::ckFetchEmail(imap,0,i,bUid,email)
        If success = 0
            Debug CkImap::ckLastErrorText(imap)
            CkImap::ckDispose(imap)
            CkEmail::ckDispose(email)
            ProcedureReturn
        EndIf

        Debug CkEmail::ckFrom(email)
        Debug CkEmail::ckSubject(email)
        Debug "----"
    Next

    ; Disconnect from the IMAP server.
    ; The SSH tunnel remains open.
    success = CkImap::ckDisconnect(imap)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; It is possible to re-use the existing SSH tunnel for the next connection:
    success = CkImap::ckConnect(imap,"imap.my-imap-server2.com")
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; Review the LastErrorText to see that the connection was made via the SSH tunnel:
    Debug CkImap::ckLastErrorText(imap)

    success = CkImap::ckDisconnect(imap)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; Finally, close the SSH tunnel.
    success = CkImap::ckSshCloseTunnel(imap)
    If success = 0
        Debug CkImap::ckLastErrorText(imap)
        CkImap::ckDispose(imap)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    Debug "IMAP SSH tunneling example completed."


    CkImap::ckDispose(imap)
    CkEmail::ckDispose(email)


    ProcedureReturn
EndProcedure