Xbase++

Connect to an SFTP Server Through a Jump Host

Demonstrates the Chilkat SFtp.ConnectThroughSsh method, which connects to an SFTP server through an already connected and authenticated Ssh object. The first argument is the jump-host Ssh object, and the second and third are the destination hostname and port.

Background: This is the "jump host" (bastion) pattern: the application connects to a reachable gateway, then tunnels onward to an SFTP server that is only accessible from inside the network. Each hop authenticates separately with its own credentials. The result is a normal SFtp object — still requiring its own authentication and InitializeSftp — that happens to be routed through the first connection.

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LOCAL nSuccess
LOCAL oSshJump
LOCAL nPort
LOCAL cPassword
LOCAL oSftp

nSuccess := 0

//  Demonstrates the SFtp.ConnectThroughSsh method, which connects to an SFTP server through an
//  already connected and authenticated Ssh object (a jump host).  The 1st argument is the Ssh
//  object, and the 2nd and 3rd are the destination hostname and port.

oSshJump := CreateObject("Chilkat.Ssh")

//  Connect and authenticate to the jump host first.
nPort := 22
nSuccess := oSshJump:Connect("jump.example.com", nPort)
IF (nSuccess == 0)
    ? oSshJump:LastErrorText
    oSshJump:destroy()
    RETURN
ENDIF

//  Normally you would not hard-code the password in source.  You should instead obtain it
//  from an interactive prompt, environment variable, or a secrets vault.
cPassword := "mySshPassword"

nSuccess := oSshJump:AuthenticatePw("myJumpLogin", cPassword)
IF (nSuccess == 0)
    ? oSshJump:LastErrorText
    oSshJump:destroy()
    RETURN
ENDIF

//  Connect to the SFTP server through the jump host.
oSftp := CreateObject("Chilkat.SFtp")
nSuccess := oSftp:ConnectThroughSsh(oSshJump, "sftp.internal.example.com", nPort)
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSshJump:destroy()
    oSftp:destroy()
    RETURN
ENDIF

//  Authenticate to the SFTP server (its own credentials), then initialize SFTP.
nSuccess := oSftp:AuthenticatePw("mySshLogin", cPassword)
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSshJump:destroy()
    oSftp:destroy()
    RETURN
ENDIF

nSuccess := oSftp:InitializeSftp()
IF (nSuccess == 0)
    ? oSftp:LastErrorText
    oSshJump:destroy()
    oSftp:destroy()
    RETURN
ENDIF

? "Connected to the SFTP server through the jump host."

oSftp:Disconnect()
oSshJump:Disconnect()

oSshJump:destroy()
oSftp:destroy()