PHP Extension

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. PHP Extension

<?php

include("chilkat.php");

$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.

$tunnel = new CkSocket();

$sshHostname = 'sftp.example.com';
$sshPort = 22;

// Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->SshOpenTunnel($sshHostname,$sshPort);
if ($success == false) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// 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) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

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

$bTls = true;
$port = 443;
$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.
$channel = new CkSocket();
$success = $tunnel->SshNewChannel('some-websocket-server.com',$port,$bTls,$maxWaitMs,$channel);
if ($success == false) {
    print $tunnel->lastErrorText() . "\n";
    exit;
}

// 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.
$rest = new CkRest();
$success = $rest->UseConnection($channel,false);
if ($success == false) {
    print $rest->lastErrorText() . "\n";
    exit;
}

// Finally, tell our WebSocket object to use the Rest object..
$ws = new CkWebSocket();

// Tell the WebSocket to use this connection.
$success = $ws->UseConnection($rest);
if ($success == false) {
    print $ws->lastErrorText() . "\n";
    exit;
}

// 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.
$responseBody = $rest->fullRequestNoBody('GET','/something');
if ($rest->get_LastMethodSuccess() == false) {
    print $rest->lastErrorText() . "\n";
    exit;
}

// 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..)
$statusCode = $rest->get_ResponseStatusCode();
print 'Response status code: ' . $statusCode . "\n";

if ($statusCode != 101) {
    print $responseBody . "\n";
    print '-- Failed because of unexpected response status code.' . "\n";
    exit;
}

// 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) {
    print $ws->lastErrorText() . "\n";
    exit;
}

print 'WebSocket connection successful.' . "\n";

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

?>