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(JavaScript) WebSocket through SSH Tunnel
This example shows how to establish a WebSocket connection through an SSH tunnel. The WebSocket protocol communications will be encapsulated within an SSH tunnel. Note: This example requires Chilkat v11.0.0 or greater.
var 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.
var tunnel = new CkSocket();
var sshHostname = "sftp.example.com";
var sshPort = 22;
// Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort);
if (success == false) {
console.log(tunnel.LastErrorText);
return;
}
// 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) {
console.log(tunnel.LastErrorText);
return;
}
// OK, the SSH tunnel is setup. Now open a channel within the tunnel.
var bTls = true;
var port = 443;
var 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.
var channel = new CkSocket();
success = tunnel.SshNewChannel("some-websocket-server.com",port,bTls,maxWaitMs,channel);
if (success == false) {
console.log(tunnel.LastErrorText);
return;
}
// 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.
var rest = new CkRest();
success = rest.UseConnection(channel,false);
if (success == false) {
console.log(rest.LastErrorText);
return;
}
// Finally, tell our WebSocket object to use the Rest object..
var ws = new CkWebSocket();
// Tell the WebSocket to use this connection.
success = ws.UseConnection(rest);
if (success == false) {
console.log(ws.LastErrorText);
return;
}
// Add the standard WebSocket open handshake headers that will be needed.
// (This adds the required HTTP request headers to the rest object.)
ws.AddClientHeaders();
// Add any additional headers that might be desired.
// Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
rest.AddHeader("Sec-WebSocket-Protocol","x-some-websocket-subprotocol");
rest.AddHeader("Origin","http://some-websocket-server.com");
// Do the open handshake.
var responseBody = rest.FullRequestNoBody("GET","/something");
if (rest.LastMethodSuccess == false) {
console.log(rest.LastErrorText);
return;
}
// 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..)
var statusCode = rest.ResponseStatusCode;
console.log("Response status code: " + statusCode);
if (statusCode !== 101) {
console.log(responseBody);
console.log("-- Failed because of unexpected response status code.");
return;
}
// 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) {
console.log(ws.LastErrorText);
return;
}
console.log("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...)
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