Perl

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. Perl

use chilkat();

$success = 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.

$tunnel = chilkat::CkSocket->new();

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

# Connect to an SSH server and establish the SSH tunnel:
$success = $tunnel->SshOpenTunnel($sshHostname,$sshPort);
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\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 == 0) {
    print $tunnel->lastErrorText() . "\r\n";
    exit;
}

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

$bTls = 1;
$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 = chilkat::CkSocket->new();
$success = $tunnel->SshNewChannel("some-websocket-server.com",$port,$bTls,$maxWaitMs,$channel);
if ($success == 0) {
    print $tunnel->lastErrorText() . "\r\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 = chilkat::CkRest->new();
$success = $rest->UseConnection($channel,0);
if ($success == 0) {
    print $rest->lastErrorText() . "\r\n";
    exit;
}

# Finally, tell our WebSocket object to use the Rest object..
$ws = chilkat::CkWebSocket->new();

# Tell the WebSocket to use this connection.
$success = $ws->UseConnection($rest);
if ($success == 0) {
    print $ws->lastErrorText() . "\r\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() == 0) {
    print $rest->lastErrorText() . "\r\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 . "\r\n";

if ($statusCode != 101) {
    print $responseBody . "\r\n";
    print "-- Failed because of unexpected response status code." . "\r\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 == 0) {
    print $ws->lastErrorText() . "\r\n";
    exit;
}

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

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