(Visual FoxPro) TCP or TLS over Multiple Hop SSH to Remote Server

Demonstrates how to use the Chilkat Socket API to connect to a remote server (using TCP or TLS) tunneled through mulitple-hop SSH. The scheme looks like this:

Application => ServerSSH1 => ServerSSH2 => DestinationServer

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

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

LOCAL loSsh1
LOCAL lnSuccess
LOCAL loSsh2
LOCAL loSocket
LOCAL lnUseTls
LOCAL lnMaxWaitMillisec
LOCAL lcResponseStatusLine
LOCAL lcResponseHeaderLine
LOCAL lcRemainderOfHeader

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

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Ssh')
loSsh1 = CreateObject('Chilkat.Ssh')

* Connect directly to the 1st SSH server.
lnSuccess = loSsh1.Connect("serverssh1.com",22)
IF (lnSuccess <> 1) THEN
    ? loSsh1.LastErrorText
    RELEASE loSsh1
    CANCEL
ENDIF

* Authenticate using login/password:
lnSuccess = loSsh1.AuthenticatePw("ssh1Login","ssh1Password")
IF (lnSuccess <> 1) THEN
    ? loSsh1.LastErrorText
    RELEASE loSsh1
    CANCEL
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.
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Ssh')
loSsh2 = CreateObject('Chilkat.Ssh')
lnSuccess = loSsh2.ConnectThroughSsh(loSsh1,"serverssh2.com",22)
IF (lnSuccess <> 1) THEN
    ? loSsh2.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    CANCEL
ENDIF

* Authenticate with ssh2...
lnSuccess = loSsh2.AuthenticatePw("ssh2Login","ssh2Password")
IF (lnSuccess <> 1) THEN
    ? loSsh2.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.Socket')
loSocket = CreateObject('Chilkat.Socket')

* Tell the socket object to connect to our destination server though the ssh2 tunnel (which itself is routed through ssh1).
* The connection looks like this:  ApplicationSocket(TLS) => ServerSSH1 => ServerSSH2 => DestinationServer
lnSuccess = loSocket.UseSsh(loSsh2)
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

* Connect using TLS to www.chilkatsoft.com
* We could also tunnel a bare TCP connection by specifying port 80 with useTls = 0.
lnUseTls = 1
lnMaxWaitMillisec = 20000
lnSuccess = loSocket.Connect("www.chilkatsoft.com",443,lnUseTls,lnMaxWaitMillisec)
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

* Once the multiple hop SSH tunneled connection is setup,  the socket programming
* is identical to the normal case where we have a direct connection.

* Tell the socket object that all text is to be sent in the utf-8 encoding,
* and the text received is assumed to be utf-8.
loSocket.StringCharset = "utf-8"

* Send an HTTP HEAD request:
lnSuccess = loSocket.SendString("HEAD / HTTP/1.1" + CHR(13) + CHR(10) + "Host: www.chilkatsoft.com" + CHR(13) + CHR(10) + CHR(13) + CHR(10))
IF (lnSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

* Wait a maximum of 4 seconds while no data is forthcoming:
loSocket.MaxReadIdleMs = 4000

* Get the 1st response line, which should be "HTTP/1.1 200 OK"
lcResponseStatusLine = loSocket.ReceiveToCRLF()
IF (loSocket.LastMethodSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

? "StatusLine: " + lcResponseStatusLine

* Now get the 1st line of the response header:
lcResponseHeaderLine = loSocket.ReceiveToCRLF()
IF (loSocket.LastMethodSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

? "HeaderLine: " + lcResponseHeaderLine

* Now read the remainder of the response header by reading until a double CRLF is seen:
lcRemainderOfHeader = loSocket.ReceiveUntilMatch(CHR(13) + CHR(10) + CHR(13) + CHR(10))
IF (loSocket.LastMethodSuccess <> 1) THEN
    ? loSocket.LastErrorText
    RELEASE loSsh1
    RELEASE loSsh2
    RELEASE loSocket
    CANCEL
ENDIF

? "Remainder: " + lcRemainderOfHeader

* Close the connection with the server.  This closes the tunnel through ssh2.
* Wait a max of 20 seconds (20000 millsec)
lnSuccess = loSocket.Close(20000)

* 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.
loSsh2.Disconnect()

loSsh1.Disconnect()

RELEASE loSsh1
RELEASE loSsh2
RELEASE loSocket