Xojo Plugin

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. Xojo Plugin

Dim success As Boolean
success = False

// 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.

Dim tunnel As New Chilkat.Socket

Dim sshHostname As String
sshHostname = "sftp.example.com"
Dim sshPort As Int32
sshPort = 22

// Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort)
If (success = False) Then
    System.DebugLog(tunnel.LastErrorText)
    Return
End If

// Authenticate with the SSH server via a login/password
// or with a public key.
// This example demonstrates SSH password authentication.
success = tunnel.SshAuthenticatePw("mySshLogin","mySshPassword")
If (success = False) Then
    System.DebugLog(tunnel.LastErrorText)
    Return
End If

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

Dim bTls As Boolean
bTls = True
Dim port As Int32
port = 443
Dim maxWaitMs As Int32
maxWaitMs = 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.
Dim channel As New Chilkat.Socket
success = tunnel.SshNewChannel("some-websocket-server.com",port,bTls,maxWaitMs,channel)
If (success = False) Then
    System.DebugLog(tunnel.LastErrorText)
    Return
End If

// 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.
Dim rest As New Chilkat.Rest
success = rest.UseConnection(channel,False)
If (success = False) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// Finally, tell our WebSocket object to use the Rest object..
Dim ws As New Chilkat.WebSocket

// Tell the WebSocket to use this connection.
success = ws.UseConnection(rest)
If (success = False) Then
    System.DebugLog(ws.LastErrorText)
    Return
End If

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

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

// Do the open handshake.
Dim responseBody As String
responseBody = rest.FullRequestNoBody("GET","/something")
If (rest.LastMethodSuccess = False) Then
    System.DebugLog(rest.LastErrorText)
    Return
End If

// 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..)
Dim statusCode As Int32
statusCode = rest.ResponseStatusCode
System.DebugLog("Response status code: " + Str(statusCode))

If (statusCode <> 101) Then
    System.DebugLog(responseBody)
    System.DebugLog("-- Failed because of unexpected response status code.")
    Return
End If

// 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. 
success = ws.ValidateServerHandshake()
If (success = False) Then
    System.DebugLog(ws.LastErrorText)
    Return
End If

System.DebugLog("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...)