(PureBasic) SMTP over Multiple Hop SSH

Demonstrates how to send email (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => SmtpServer

The ConnectThroughSsh and UseSsh methods are added in Chilkat version 9.5.0.55 to accomplish this task.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkSsh.pb"
IncludeFile "CkEmail.pb"
IncludeFile "CkMailMan.pb"

Procedure ChilkatExample()

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

    ssh1.i = CkSsh::ckCreate()
    If ssh1.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; Connect directly to the 1st SSH server.
    success.i = CkSsh::ckConnect(ssh1,"serverssh1.com",22)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh1)
        CkSsh::ckDispose(ssh1)
        ProcedureReturn
    EndIf

    ; Authenticate using login/password:
    success = CkSsh::ckAuthenticatePw(ssh1,"ssh1Login","ssh1Password")
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh1)
        CkSsh::ckDispose(ssh1)
        ProcedureReturn
    EndIf

    ; Connect through the 1st SSH connection to reach a 2nd SSH server.
    ; Note: Any number of SSH connections may be simultaneously tunneled through a single
    ; existing SSH connection.
    ssh2.i = CkSsh::ckCreate()
    If ssh2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkSsh::ckConnectThroughSsh(ssh2,ssh1,"serverssh2.com",22)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh2)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        ProcedureReturn
    EndIf

    ; Authenticate with ssh2...
    success = CkSsh::ckAuthenticatePw(ssh2,"ssh2Login","ssh2Password")
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh2)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        ProcedureReturn
    EndIf

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

    ; Tell the mailman object to connect to the SMTP server though the ssh2 tunnel (which itself is routed through ssh1).
    ; The connection looks like this:  Application => ServerSSH1 => ServerSSH2 => SMTPServer
    success = CkMailMan::ckUseSsh(mailman,ssh2)
    If success <> 1
        Debug CkMailMan::ckLastErrorText(mailman)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        CkMailMan::ckDispose(mailman)
        ProcedureReturn
    EndIf

    ; Set the SMTP server.
    CkMailMan::setCkSmtpHost(mailman, "smtp.someserver.com")

    ; Set the SMTP login/password (if required)
    CkMailMan::setCkSmtpUsername(mailman, "myUsername")
    CkMailMan::setCkSmtpPassword(mailman, "myPassword")

    ; Create a new email object
    email.i = CkEmail::ckCreate()
    If email.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkEmail::setCkSubject(email, "This is a test")
    CkEmail::setCkBody(email, "This is a test")
    CkEmail::setCkFrom(email, "Chilkat Support <support@chilkatsoft.com>")
    success = CkEmail::ckAddTo(email,"Chilkat Admin","admin@chilkatsoft.com")

    success = CkMailMan::ckSendEmail(mailman,email)
    If success <> 1
        Debug CkMailMan::ckLastErrorText(mailman)
        CkSsh::ckDispose(ssh1)
        CkSsh::ckDispose(ssh2)
        CkMailMan::ckDispose(mailman)
        CkEmail::ckDispose(email)
        ProcedureReturn
    EndIf

    ; Close the connection with the server.  This closes the tunnel through ssh2.
    success = CkMailMan::ckCloseSmtpConnection(mailman)
    If success <> 1
        Debug "Connection to SMTP server not closed cleanly."
    EndIf

    Debug "Mail Sent!"

    ; Close the connection with ssh2.  (This closes the the tunnel through ssh1.)
    ; The connection with ssh1 is still alive, and may be used for more connections.
    CkSsh::ckDisconnect(ssh2)

    CkSsh::ckDisconnect(ssh1)


    CkSsh::ckDispose(ssh1)
    CkSsh::ckDispose(ssh2)
    CkMailMan::ckDispose(mailman)
    CkEmail::ckDispose(email)


    ProcedureReturn
EndProcedure