(PureBasic) SSH Tunnel (Port Forwarding via direct-tcpip channel)

Demonstrates how to create an SSH tunnel to a remote hostname:port via a direct-tcpip channel.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkSsh.pb"

Procedure ChilkatExample()

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

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

    ; Connect to an SSH server:
    hostname.s
    port.i

    ; Hostname may be an IP address or hostname:
    hostname = "192.168.1.117"
    port = 22

    success.i = CkSsh::ckConnect(ssh,hostname,port)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh)
        CkSsh::ckDispose(ssh)
        ProcedureReturn
    EndIf

    ; Wait a max of 5 seconds when reading responses..
    CkSsh::setCkIdleTimeoutMs(ssh, 5000)

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

    ; Open a direct-tcpip channel.  We want the SSH server to connect
    ; to www.chilkatsoft.com, port 80 (i.e. the web server).
    ; Data sent through the SSH tunnel is forwarded to the remote
    ; host:port.  (Note: The remote host:port does not need to be 
    ; a web server.  It can be anything.  It can be your own
    ; customer application server that listens on a port, or any
    ; other type of server.)
    ; When we read from the SSH channel, we'll be reading data
    ; sent from the remote host:port (i.e. the web server in this
    ; example).
    channelNum.i
    channelNum = CkSsh::ckOpenDirectTcpIpChannel(ssh,"www.chilkatsoft.com",80)
    If channelNum < 0
        Debug CkSsh::ckLastErrorText(ssh)
        CkSsh::ckDispose(ssh)
        ProcedureReturn
    EndIf

    ; Build a simple HTTP GET request for http://www.chilkatsoft.com/xyz.html
    httpReq.s = "GET /xyz123.html HTTP/1.1" + Chr(13) + Chr(10) + "Host: www.chilkatsoft.com" + Chr(13) + Chr(10) + Chr(13) + Chr(10)

    ; Send the HTTP request:
    success = CkSsh::ckChannelSendString(ssh,channelNum,httpReq,"ansi")
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh)
        CkSsh::ckDispose(ssh)
        ProcedureReturn
    EndIf

    ; Get the HTTP response.
    ; First read the HTTP response header which ends with a double CRLF.
    ; Calling ChannelReceiveUntilMatch will receive until match string is seen,
    ; or until a timeout occurs (IdleTimeoutMs property).  ChannelReceiveUntilMatch
    ; may read beyond the match string, but it will stop reading as soon as the match
    ; string is seen.
    caseSensitive.i = 0
    matchStr.s = Chr(13) + Chr(10) + Chr(13) + Chr(10)
    success = CkSsh::ckChannelReceiveUntilMatch(ssh,channelNum,matchStr,"ansi",caseSensitive)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh)
        CkSsh::ckDispose(ssh)
        ProcedureReturn
    EndIf

    ; Extract the HTTP header from the receive buffer.
    ; (GetReceiveTextS extracts up to and including the match string from the receive buffer)
    responseHeader.s
    responseHeader = CkSsh::ckGetReceivedTextS(ssh,channelNum,matchStr,"ansi")
    Debug "---- HTTP Response Header ----"
    Debug responseHeader

    ; Now get the body of the HTTP response (this is the HTML content
    ; of http://www.chilkatsoft.com/xyz.html
    ; It's possible we've already received the entire HTTP response in the
    ; call to ChannelReceiveUntilMatch.  Therefore, we'll poll for any remaining data
    ; and wait a max of .2 seconds.
    numBytesRead.i
    pollTimeoutMs.i = 200
    numBytesRead = CkSsh::ckChannelPoll(ssh,channelNum,pollTimeoutMs)
    ; We're not checking for an error here.
    ; A return value of -2 means that no data was available and the poll simply timed out (not an error)
    ; A return value of -1 indicates an error.
    ; A return value greater than 0 indicates that additional data was received.

    Debug "---- HTML BODY ----"

    ; Extract the remainder of the accumulated data in the internal receive buffer.
    ; This should be our HTML body:
    htmlBody.s
    htmlBody = CkSsh::ckGetReceivedText(ssh,channelNum,"ansi")
    Debug htmlBody

    ; Close the channel:
    success = CkSsh::ckChannelSendClose(ssh,channelNum)
    If success <> 1
        Debug CkSsh::ckLastErrorText(ssh)
        CkSsh::ckDispose(ssh)
        ProcedureReturn
    EndIf

    ; Disconnect
    CkSsh::ckDisconnect(ssh)


    CkSsh::ckDispose(ssh)


    ProcedureReturn
EndProcedure