(Python) 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.

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import sys
import chilkat

#  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()

sshHostname = "www.my-ssh-server.com"
sshPort = 22

#  Connect to an SSH server and establish the SSH tunnel:
success = tunnel.SshOpenTunnel(sshHostname,sshPort)
if (success != True):
    print(tunnel.lastErrorText())
    sys.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 != True):
    print(tunnel.lastErrorText())
    sys.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 SshOpenChannel.
# channel is a CkSocket
channel = tunnel.SshOpenChannel("some-websocket-server.com",port,bTls,maxWaitMs)
if (tunnel.get_LastMethodSuccess() != True):
    print(tunnel.lastErrorText())
    sys.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()
success = rest.UseConnection(channel,False)
if (success != True):
    print(rest.lastErrorText())

    sys.exit()

#  Finally, tell our WebSocket object to use the Rest object..
ws = chilkat.CkWebSocket()

#  Tell the WebSocket to use this connection.
success = ws.UseConnection(rest)
if (success != True):
    print(ws.lastErrorText())
    sys.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() != True):
    print(rest.lastErrorText())
    sys.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: " + str(statusCode))

if (statusCode != 101):
    print(responseBody)
    print("-- Failed because of unexpected response status code.")
    sys.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 != True):
    print(ws.lastErrorText())
    sys.exit()

print("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...)