Xbase++ Requires Chilkat v11.0.0+

WebSocket through SSH Tunnel

See more WebSocket Examples

This example shows how to establish a WebSocket connection through an SSH tunnel. The WebSocket protocol communications will be encapsulated within an SSH tunnel. Xbase++

LOCAL nSuccess
LOCAL oTunnel
LOCAL cSshHostname
LOCAL nSshPort
LOCAL nBTls
LOCAL nPort
LOCAL nMaxWaitMs
LOCAL oChannel
LOCAL oRest
LOCAL oWs
LOCAL cResponseBody
LOCAL nStatusCode

nSuccess := 0

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

//  --------------------------------------------------
//  This example borrows the code from the REST through SSH Tunnel example.
//  We first use the Chilkat Socket object to establish a connection to the WebSocket server through an SSH Tunnel.
//  Next, the Rest object uses the Socket object for its connection.
//  Finally, the WebSocket object uses the Rest object for its connection.  
//  
//  Hopefully the flexibility of this architecture is easy to see.  All of the HTTP functionality of the Rest object,
//  such as HTTP authentication, custom headers, etc. is available to the WebSocket.  Likewise, all of the advanced functionality
//  of the Socket object is in turn available to the Rest object.  

//  The high-level steps for accomplishing the task of running the WebSocket protocol through an SSH accomplished as follows:
//  1) Create the SSH tunnel using Chilkat Socket.
//  2) Open a port-forwarding channel (to the WebSocket server) within the tunnel.
//  2) Tell Rest to use the Socket object.
//  3) Tell WebSocket to use the Rest object.

oTunnel := CreateObject("Chilkat.Socket")

cSshHostname := "sftp.example.com"
nSshPort := 22

//  Connect to an SSH server and establish the SSH tunnel:
nSuccess := oTunnel:SshOpenTunnel(cSshHostname, nSshPort)
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//  Authenticate with the SSH server via a login/password
//  or with a public key.
//  This example demonstrates SSH password authentication.
nSuccess := oTunnel:SshAuthenticatePw("mySshLogin", "mySshPassword")
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    RETURN
ENDIF

//   OK, the SSH tunnel is setup.  Now open a channel within the tunnel.

nBTls := 1
nPort := 443
nMaxWaitMs := 5000

//  This returns a socket object that is a single channel within the SSH tunnel.
//  The SSH channel is our logical port-forwarded connection through the SSH tunnel.
//  Note: This example establishes a TLS connection to the target WebSocket server.
//  (The TLS protocol will run on the logical channel within the SSH tunnel.)
//  Your application can just as easily make a non-TLS connection by changing the arguments
//  passed to SshNewChannel.
oChannel := CreateObject("Chilkat.Socket")
nSuccess := oTunnel:SshNewChannel("some-websocket-server.com", nPort, nBTls, nMaxWaitMs, oChannel)
IF (nSuccess == 0)
    ? oTunnel:LastErrorText
    oTunnel:destroy()
    oChannel:destroy()
    RETURN
ENDIF

//  Create a REST object and tell it to use the SSH channel.
//  This connection is a TLS running on an SSH channel through an SSH tunnel.
//  In other words, TLS is wrapped within the SSH tunnel.
oRest := CreateObject("Chilkat.Rest")
nSuccess := oRest:UseConnection(oChannel, 0)
IF (nSuccess == 0)
    ? oRest:LastErrorText
    oTunnel:destroy()
    oChannel:destroy()
    oRest:destroy()
    RETURN
ENDIF

//  Finally, tell our WebSocket object to use the Rest object..
oWs := CreateObject("Chilkat.WebSocket")

//  Tell the WebSocket to use this connection.
nSuccess := oWs:UseConnection(oRest)
IF (nSuccess == 0)
    ? oWs:LastErrorText
    oTunnel:destroy()
    oChannel:destroy()
    oRest:destroy()
    oWs:destroy()
    RETURN
ENDIF

//  Add the standard WebSocket open handshake headers that will be needed.
//  (This adds the required HTTP request headers to the rest object.)
oWs:AddClientHeaders()

//  Add any additional headers that might be desired.
//  Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
oRest:AddHeader("Sec-WebSocket-Protocol", "x-some-websocket-subprotocol")
oRest:AddHeader("Origin", "http://some-websocket-server.com")

//  Do the open handshake.
cResponseBody := oRest:FullRequestNoBody("GET", "/something")
IF (oRest:LastMethodSuccess == 0)
    ? oRest:LastErrorText
    oTunnel:destroy()
    oChannel:destroy()
    oRest:destroy()
    oWs:destroy()
    RETURN
ENDIF

//  If successful, the HTTP response status code should be 101,
//  and the response body will be empty. (If it failed, we'll have a look
//  at the response body..)
nStatusCode := oRest:ResponseStatusCode
? "Response status code: " + Str(nStatusCode)

IF (nStatusCode != 101)
    ? cResponseBody
    ? "-- Failed because of unexpected response status code."
    oTunnel:destroy()
    oChannel:destroy()
    oRest:destroy()
    oWs:destroy()
    RETURN
ENDIF

//  We have the expected 101 response, so let's now validate the 
//  contents of the response, such as the value sent by the server in the
//  Sec-WebSocket-Accept header. 
nSuccess := oWs:ValidateServerHandshake()
IF (nSuccess == 0)
    ? oWs:LastErrorText
    oTunnel:destroy()
    oChannel:destroy()
    oRest:destroy()
    oWs:destroy()
    RETURN
ENDIF

? "WebSocket connection successful."

//  The application may now begin sending and receiving frames on the WebSocket connection.
//  (At this point, we're done with the rest object...)

oTunnel:destroy()
oChannel:destroy()
oRest:destroy()
oWs:destroy()