(C) 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++ Linux/CentOS C/C++ Alpine Linux C/C++ MAC OS X C/C++	armhf/aarch64 C/C++ C++ Builder iOS C/C++ Android C/C++	Solaris C/C++ MinGW C/C++

#include <C_CkSocket.h>
#include <C_CkRest.h>
#include <C_CkWebSocket.h>

void ChilkatSample(void)
    {
    HCkSocket tunnel;
    const char *sshHostname;
    int sshPort;
    BOOL success;
    HCkSocket channel;
    BOOL bTls;
    int port;
    int maxWaitMs;
    HCkRest rest;
    HCkWebSocket ws;
    const char *responseBody;
    int statusCode;

    //  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 = CkSocket_Create();

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

    //  Connect to an SSH server and establish the SSH tunnel:
    success = CkSocket_SshOpenTunnel(tunnel,sshHostname,sshPort);
    if (success != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(tunnel));
        CkSocket_Dispose(tunnel);
        return;
    }

    //  Authenticate with the SSH server via a login/password
    //  or with a public key.
    //  This example demonstrates SSH password authentication.
    success = CkSocket_SshAuthenticatePw(tunnel,"mySshLogin","mySshPassword");
    if (success != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(tunnel));
        CkSocket_Dispose(tunnel);
        return;
    }

    //   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 = CkSocket_SshOpenChannel(tunnel,"some-websocket-server.com",port,bTls,maxWaitMs);
    if (CkSocket_getLastMethodSuccess(tunnel) != TRUE) {
        printf("%s\n",CkSocket_lastErrorText(tunnel));
        CkSocket_Dispose(tunnel);
        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.
    rest = CkRest_Create();
    success = CkRest_UseConnection(rest,channel,FALSE);
    if (success != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkSocket_Dispose(channel);
        CkSocket_Dispose(tunnel);
        CkRest_Dispose(rest);
        return;
    }

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

    //  Tell the WebSocket to use this connection.
    success = CkWebSocket_UseConnection(ws,rest);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkSocket_Dispose(tunnel);
        CkRest_Dispose(rest);
        CkWebSocket_Dispose(ws);
        return;
    }

    //  Add the standard WebSocket open handshake headers that will be needed.
    //  (This adds the required HTTP request headers to the rest object.)
    CkWebSocket_AddClientHeaders(ws);

    //  Add any additional headers that might be desired.
    //  Two common WebSocketSpecific headers are "Sec-WebSocket-Protocol" and "Origin".
    CkRest_AddHeader(rest,"Sec-WebSocket-Protocol","x-some-websocket-subprotocol");
    CkRest_AddHeader(rest,"Origin","http://some-websocket-server.com");

    //  Do the open handshake.
    responseBody = CkRest_fullRequestNoBody(rest,"GET","/something");
    if (CkRest_getLastMethodSuccess(rest) != TRUE) {
        printf("%s\n",CkRest_lastErrorText(rest));
        CkSocket_Dispose(tunnel);
        CkRest_Dispose(rest);
        CkWebSocket_Dispose(ws);
        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..)
    statusCode = CkRest_getResponseStatusCode(rest);
    printf("Response status code: %d\n",statusCode);

    if (statusCode != 101) {
        printf("%s\n",responseBody);
        printf("-- Failed because of unexpected response status code.\n");
        CkSocket_Dispose(tunnel);
        CkRest_Dispose(rest);
        CkWebSocket_Dispose(ws);
        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 = CkWebSocket_ValidateServerHandshake(ws);
    if (success != TRUE) {
        printf("%s\n",CkWebSocket_lastErrorText(ws));
        CkSocket_Dispose(tunnel);
        CkRest_Dispose(rest);
        CkWebSocket_Dispose(ws);
        return;
    }

    printf("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...)


    CkSocket_Dispose(tunnel);
    CkRest_Dispose(rest);
    CkWebSocket_Dispose(ws);

    }