Unicode 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. Unicode C

#include <C_CkSocketW.h>
#include <C_CkRestW.h>
#include <C_CkWebSocketW.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkSocketW tunnel;
    const wchar_t *sshHostname;
    int sshPort;
    BOOL bTls;
    int port;
    int maxWaitMs;
    HCkSocketW channel;
    HCkRestW rest;
    HCkWebSocketW ws;
    const wchar_t *responseBody;
    int statusCode;

    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.

    tunnel = CkSocketW_Create();

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

    // Connect to an SSH server and establish the SSH tunnel:
    success = CkSocketW_SshOpenTunnel(tunnel,sshHostname,sshPort);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_Dispose(tunnel);
        return;
    }

    // Authenticate with the SSH server via a login/password
    // or with a public key.
    // This example demonstrates SSH password authentication.
    success = CkSocketW_SshAuthenticatePw(tunnel,L"mySshLogin",L"mySshPassword");
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_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 SshNewChannel.
    channel = CkSocketW_Create();
    success = CkSocketW_SshNewChannel(tunnel,L"some-websocket-server.com",port,bTls,maxWaitMs,channel);
    if (success == FALSE) {
        wprintf(L"%s\n",CkSocketW_lastErrorText(tunnel));
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        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 = CkRestW_Create();
    success = CkRestW_UseConnection(rest,channel,FALSE);
    if (success == FALSE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        CkRestW_Dispose(rest);
        return;
    }

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

    // Tell the WebSocket to use this connection.
    success = CkWebSocketW_UseConnection(ws,rest);
    if (success == FALSE) {
        wprintf(L"%s\n",CkWebSocketW_lastErrorText(ws));
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        CkRestW_Dispose(rest);
        CkWebSocketW_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.)
    CkWebSocketW_AddClientHeaders(ws);

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

    // Do the open handshake.
    responseBody = CkRestW_fullRequestNoBody(rest,L"GET",L"/something");
    if (CkRestW_getLastMethodSuccess(rest) == FALSE) {
        wprintf(L"%s\n",CkRestW_lastErrorText(rest));
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        CkRestW_Dispose(rest);
        CkWebSocketW_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 = CkRestW_getResponseStatusCode(rest);
    wprintf(L"Response status code: %d\n",statusCode);

    if (statusCode != 101) {
        wprintf(L"%s\n",responseBody);
        wprintf(L"-- Failed because of unexpected response status code.\n");
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        CkRestW_Dispose(rest);
        CkWebSocketW_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 = CkWebSocketW_ValidateServerHandshake(ws);
    if (success == FALSE) {
        wprintf(L"%s\n",CkWebSocketW_lastErrorText(ws));
        CkSocketW_Dispose(tunnel);
        CkSocketW_Dispose(channel);
        CkRestW_Dispose(rest);
        CkWebSocketW_Dispose(ws);
        return;
    }

    wprintf(L"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...)


    CkSocketW_Dispose(tunnel);
    CkSocketW_Dispose(channel);
    CkRestW_Dispose(rest);
    CkWebSocketW_Dispose(ws);

    }