(MFC) WebSocket Connect through HTTP Proxy

This example shows how to establish a WebSocket connection through an HTTP proxy server.

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

See Also: Using MFC CString in Chilkat

#include <CkRest.h>
#include <CkSocket.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 using HTTP Proxy example.
    //  We first use the Chilkat Socket object to establish a connection to the WebSocket server through an HTTP proxy.
    //  Next, the Rest object uses the Socket object for its connection.
    //  Finally, the WebSocket object uses the Rest object for its connection.
    // 

    CkRest rest;
    CkSocket socket;

    //  Set the HTTP proxy domain or IP address, and port.
    socket.put_HttpProxyHostname("192.168.1.79");
    socket.put_HttpProxyPort(808);

    //  Provide authentication to the HTTP proxy, if needed.
    socket.put_HttpProxyUsername("HTTP_PROXY_LOGIN");
    socket.put_HttpProxyPassword("HTTP_PROXY_PASSWORD");
    socket.put_HttpProxyAuthMethod("Basic");

    //  Indicate that HTTP requests (i.e. the WebSocket opening handshake) will be sent over the socket.
    //  This is important for how the HTTP proxy connection is established.
    socket.put_HttpProxyForHttp(true);

    //  Connect to the websocket server through the HTTP proxy.
    bool bTls = false;
    int port = 80;
    int maxWaitMs = 5000;
    bool success = socket.Connect("some-websocket-server.com",port,bTls,maxWaitMs);
    if (success != true) {
        strOut.append("Connect Failure Error Code: ");
        strOut.appendInt(socket.get_ConnectFailReason());
        strOut.append("\r\n");
        strOut.append(socket.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    //  Tell the Rest object to use the connected socket.
    success = rest.UseConnection(socket,true);
    if (success != true) {
        strOut.append(rest.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    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 and socket objects...)

    strOut.append("Success.");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }