(MFC) 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.

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

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

void ChilkatSample(void)
    {
    CkString strOut;

    //  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 = "www.my-ssh-server.com";
    int sshPort = 22;

    //  Connect to an SSH server and establish the SSH tunnel:
    bool success = tunnel.SshOpenTunnel(sshHostname,sshPort);
    if (success != true) {
        strOut.append(tunnel.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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 != true) {
        strOut.append(tunnel.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //   OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
    CkSocket *channel = 0;

    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 SshOpenChannel.
    channel = tunnel.SshOpenChannel("some-websocket-server.com",port,bTls,maxWaitMs);
    if (tunnel.get_LastMethodSuccess() != true) {
        strOut.append(tunnel.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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 != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        delete channel;
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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 != true) {
        strOut.append(ws.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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() != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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();
    strOut.append("Response status code: ");
    strOut.appendInt(statusCode);
    strOut.append("\r\n");

    if (statusCode != 101) {
        strOut.append(responseBody);
        strOut.append("\r\n");
        strOut.append("-- Failed because of unexpected response status code.");
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        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 != true) {
        strOut.append(ws.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append("WebSocket connection successful.");
    strOut.append("\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...)


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }