C++

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. C++

#include <CkSocket.h>
#include <CkRest.h>
#include <CkWebSocket.h>

void ChilkatSample(void)
    {
    bool 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.

    CkSocket tunnel;

    const char *sshHostname = "sftp.example.com";
    int sshPort = 22;

    // Connect to an SSH server and establish the SSH tunnel:
    success = tunnel.SshOpenTunnel(sshHostname,sshPort);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        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) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        return;
    }

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

    bool bTls = true;
    int port = 443;
    int 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.
    CkSocket channel;
    success = tunnel.SshNewChannel("some-websocket-server.com",port,bTls,maxWaitMs,channel);
    if (success == false) {
        std::cout << tunnel.lastErrorText() << "\r\n";
        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.
    CkRest rest;
    success = rest.UseConnection(channel,false);
    if (success == false) {
        std::cout << rest.lastErrorText() << "\r\n";
        return;
    }

    // Finally, tell our WebSocket object to use the Rest object..
    CkWebSocket ws;

    // Tell the WebSocket to use this connection.
    success = ws.UseConnection(rest);
    if (success == false) {
        std::cout << ws.lastErrorText() << "\r\n";
        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.
    const char *responseBody = rest.fullRequestNoBody("GET","/something");
    if (rest.get_LastMethodSuccess() == false) {
        std::cout << rest.lastErrorText() << "\r\n";
        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..)
    int statusCode = rest.get_ResponseStatusCode();
    std::cout << "Response status code: " << statusCode << "\r\n";

    if (statusCode != 101) {
        std::cout << responseBody << "\r\n";
        std::cout << "-- Failed because of unexpected response status code." << "\r\n";
        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) {
        std::cout << ws.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "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...)
    }