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Figure 2 Simple Hyperlink Navigation APIs

Function
Description
HlinkSimpleNavigateToString
Executes a hyperlink jump to a new document or object represented as a string
HlinkSimpleNavigateToMoniker
Executes a hyperlink jump to a new document or object represented as a moniker
HlinkGoBack
Executes a hyperlink jump backwards within the navigation stack
HlinkGoForward
Executes a hyperlink jump forwards within the navigation stack

Figure 4 WM_CONTEXTMENU Message Handler

 void CScribView::OnContextMenu(CWnd* pWnd, CPoint point) 
{
    CRect rect;
    GetClientRect (&rect);
    ClientToScreen (&rect);

    if (rect.PtInRect (point))
    {
        CMenu menu;
        menu.LoadMenu (IDR_CONTEXTMENU);
        CMenu* pContextMenu = menu.GetSubMenu (0);

        // If the Scribble application is not hosted in a frame that
        // is capable of hosting ActiveX Document Objects, disable the
        // "Go Back" and "Go Forward" menu items.  The Simple
        // Hyperlink Navigation APIs related to Go Back and Go Forward
        // only work in-frame.
        CScribDoc* pScribDocument = GetDocument ();
        if (!pScribDocument -> IsDocObject())
        {
            pContextMenu -> EnableMenuItem(ID_GOBACK, MF_GRAYED);
            pContextMenu -> EnableMenuItem(ID_GOFORWARD, MF_GRAYED);
        }

        // Display the context menu.
        pContextMenu -> TrackPopupMenu (TPM_LEFTALIGN | TPM_LEFTBUTTON |
                                        TPM_RIGHTBUTTON, point.x, 
                                        point.y, this);
    }
}

Figure 5 Context Menu Item Message Handlers

 ////////////////////////////////////////////////////////////////////
//
//    OnGoBack: Context menu handler for "Go Back".  Calls the
//              Simple Hyperlink Navigation API HlinkGoBack to go
//              back in the Hyperlink history stack.
//
////////////////////////////////////////////////////////////////////
void CScribDoc::OnGoBack()
{
  IUnknown* pUnk = NULL;

  // Obtain the IUnknown pointer to the document.
  HRESULT hr = this -> ExternalQueryInterface ((void*)&IID_IUnknown,
                                               LPVOID *)&pUnk);

  if (hr == S_OK)
    // Go Back in the hyperlink history stack
    HlinkGoBack (pUnk);
}

///////////////////////////////////////////////////////////////////
//    OnGoForward:  Context menu handler for "Go Back".  Calls
//                  the Simple Hyperlink Navigation API HlinkGoForward
//                  to go forward in the Hyperlink history stack.
//
///////////////////////////////////////////////////////////////////
void CScribDoc::OnGoForward()
{
  IUnknown* pUnk = NULL;

  // Obtain the IUnknown pointer to the document.
  HRESULT hr = this -> ExternalQueryInterface ((void*)&IID_IUnknown,
                                               LPVOID *)&pUnk);

  if (hr == S_OK)
    // Go Forward in the hyperlink history stack
    hr = HlinkGoForward (pUnk);
}

///////////////////////////////////////////////////////////////////
//
//    OnMSHomePage:  Context menu handler for "Microsoft Home Page".
//                   Calls the Simple Hyperlink Hyperlink Navigation
//                   API HlinkSimpleNavigateToString to display the
//                   HTML page for Microsoft's Web site
//
///////////////////////////////////////////////////////////////////
void CScribDoc::OnMSHomePage()
{
  HRESULT hr;
  IUnknown* pUnk = NULL;

  if (this -> IsDocObject())
    // Obtain the IUnknown pointer to the document.
    hr = this -> ExternalQueryInterface ((void*)&IID_IUnknown,
                                         LPVOID *)&pUnk);

  HlinkSimpleNavigateToString(L"http://www.microsoft.com/default.htm",
                              NULL, NULL, pUnk, 0, NULL, NULL, 0);
}

Figure 8 URL Open Stream Functions

Function
Description
URLOpenStream
Creates a push-type stream object from a URL
URLOpenBlockingStream
Creates a blocking-type stream object from a URL
URLDownloadToFile
Downloads bits from the Internet and saves them to a file
URLOpenPullStream
Creates a pull-type stream object from a URL
URLOpenHttpStream
Advanced function for doing more sophisticated HTTP and FTP downloads, such as performing an HTTP POST

Figure 9 IBindStatusCallback Interface

 interface IBindStatusCallback: IUnknown
    {
    HRESULT GetBindInfo([out] DWORD* pgrfBINDF, 
                        [in, out] BINDINFO* pbindinfo);
    HRESULT OnStartBinding([in] DWORD dwReserved, [in] IBinding* pbinding);
    HRESULT GetPriority([out] LONG* pnPriority);
    HRESULT OnProgress([in] ULONG ulProgress, [in] ULONG ulProgressMax, 
                       [in] ULONG ulStatusCode, [in] LPCWSTR szStatusText);
    HRESULT OnDataAvailable([in] DWORD grfBSC, [in] DWORD dwSize, [in]
                            FORMATETC* pformatetc, [in] STGMEDIUM*   pstgmed);
    HRESULT OnObjectAvailable( [in] REFIID riid, [in] IUnknown *punk);
    HRESULT OnLowResource([in] DWORD dwReserved);
    HRESULT OnStopBinding([in] HRESULT hrStatus, [in] LPCWSTR szStatusText);
    };

Figure 10 IBindStatusCallback Implementation

Function
Implementation
URLOpenStream
Mandatory
URLOpenBlockingStream
Optional
URLDownloadToFile
Optional
URLOpenPullStream
Mandatory
URLOpenHttpStream
Optional

Figure 11 PushCBindStatusCallback::OnDataAvailable

 HRESULT CBindStatusCallback::OnDataAvailable 
(DWORD grfBSCF, DWORD dwSize, FORMATETC* pfmtetc, STGMEDIUM* pstgmed)
{
.
.
.
    if (dwSize < sizeof(BITMAPINFOHEADER) )
        return (NOERROR);  // not enough has been read yet

    // if we did not get the header information, read it now
    if (!g_bGotInfoHeader)
    {
        if (pstgmed->pstm != NULL)
        {
            DWORD dwRead;
            HRESULT hr = pstgmed->pstm->Read (&bmih, sizeof(bmih), &dwRead);

            if (SUCCEEDED(hr))
            {
                g_bGotInfoHeader = TRUE;
                return(hr);
            }
        }
    }
.
.
.
}

Figure 12 PullCBindStatusCallback::OnDataAvailable

 HRESULT CBindStatusCallback::OnDataAvailable (DWORD grfBSCF, DWORD dwSize,
                                              FORMATETC* pfmtetc, 
                                              STGMEDIUM* pstgmed)
{
    HRESULT hr = NOERROR;
    DWORD dwAmountToRead = dwSize - m_readSoFar;
    BYTE *buffer = new BYTE [dwAmountToRead];

    while (TRUE)
    {
        DWORD dwRead;

        hr = pstgmed->pstrm->Read (buffer, dwAmountToRead, &dwRead);

        if (hr == E_PENDING)
        {
            // we'll get notified again when more data comes
            return (NOERROR);
        }

        if (SUCCEEDED(hr))
        {
            // ok, process bits .... and keep looping
        }
        else
        {
            // we have an error...
            return(hr);
        }
    }
}

Figure 13 Members of the UOS Structure

Member
Description
ULONG ulSize
Size of this structure.
LPUNKNOWN punkCaller
Pointer to the controlling IUnknown of the calling ActiveX component (if the caller is an ActiveX component). If the caller is not an ActiveX component, this value may be set to NULL. Otherwise, the caller is a COM object that is contained in another component (such as an ActiveX control in the context of an HTML page). The argument represents the outermost IUnknown of the calling component. The function will attempt the download in the context of the ActiveX client framework and allow the caller's container to receive callbacks on the progress of the download.
LPCTSTR szURL
URL to be downloaded.
LPCTSTR szVerb
GET, PUT, POST, or a custom verb understood by the server. If NULL, GET is assumed.
LPCTSTR szHeaders
HTTP headers to use during connection to server. Can be NULL.
LPBYTE szPostData
Additional data to send after the headers. Typically this will be a POST data arguments. Can be NULL.
ULONG ulPostDataLen
Size of szPostData. Must not be 0 if szPostData is not NULL.
ULONG fURLEncode
Flags with either the UOS_URLENCODPOSTDATA, UOS_URLENCODEURL, or can be NULL. The two flags can be combined by a bitwise OR.
ULONG ulMode
Can be one of UOSM_PUSH, UOSM_PULL, UOS_BLOCK, or UOS_FILE. Each of these maps to one of the functions above and makes this function's programming model fit the corresponding function.
LPCTSTR szFileName
Name of the local file to write URL data to if ulMode is UOS_FILE. Otherwise, must be NULL.
LPSTREAM *ppStream
Pointer to IStream pointer if ulMode is UOS_BLOCK. Otherwise, must be NULL.
LPBINDSTATUSCALLBACK lpbscb
Pointer to IBindStatusCallback interface. This interface and the caller's programming model responsibility depend on the ulMode flag above. The function will behave exactly like the corresponding UOS functions above, depending on the flag settings.

Figure 15 AVIDNLDR Retrieve Button Message Handler

 ///////////////////////////////////////////////////////////////////
// CAVIDownloaderDlg::OnBtnRetrieve - Message handler for the Retrieve
// command button.  Downloads the .AVI file from the Internet and runs // it in the Media Architects Video Play OCX Control.
//
///////////////////////////////////////////////////////////////////
void CAVIDownloaderDlg::OnBtnRetrieve() 
{
    // This application does not do any checking to insure that the
    // user has entered a valid URL.  This exercise is left to the
    // reader.

    // Create a IBindStatusCallback object 
    ptrURLDownloadToFileCallback pURLDownloadToFileCallback;

    if (!pURLDownloadToFileCallback)
    {
        AfxMessageBox (_T("Unable to create IBindStatusCallback object."));
        return;
    }

    // Disable the "Retrieve" button    
    m_btnRetrieve.EnableWindow(FALSE);
    BeginWaitCursor();

    // Create a temporary file to hold the the .AVI file.  This demo
    // does not manage files.
    LPTSTR lpTempFileName = new TCHAR[MAX_PATH];
    LPTSTR lpPathName= new TCHAR[MAX_PATH];

    // Retrieve the path of the directory designated for temporary
    // files.
    ::GetTempPath(MAX_PATH,lpPathName);

    // Create a name for a temporary file.
    if (0 != GetTempFileName (lpPathName, _T("AVI"), 0,
           lpTempFileName))
    {
        // Swap out the .TMP extension with .AVI
        CString szFileName = lpTempFileName;
        szFileName = szFileName.Left ((szFileName.GetLength() - 3)) +
              _T("AVI");

        // Call the UOS function to do the file download
        CString szURL;
        m_URLString.GetWindowText (szURL);
        HRESULT hr = URLDownloadToFile (NULL, szURL, szFileName, 0,
              pURLDownloadToFileCallback);

        if ((hr == S_OK) && (pURLDownloadToFileCallback -> got_File ()
               == TRUE))
        {
            // Setup the Media Architects Video Play OCX Control
            // and play the .AVI file that was downloaded.
            m_VideoPlay.SetFilename (szFileName);
            m_VideoPlay.SetLoop (TRUE);

           // Play the entire video
           VARIANT varEntireVideo;
           varEntireVideo.vt = VT_ERROR;
           m_VideoPlay.Play (varEntireVideo, varEntireVideo);
        }
    }

    delete [] lpTempFileName;
    delete [] lpPathName;

    pURLDownloadToFileCallback -> Release();

    m_btnRetrieve.EnableWindow(TRUE);
    EndWaitCursor();
}

Function	Description
HlinkSimpleNavigateToString	Executes a hyperlink jump to a new document or object represented as a string
HlinkSimpleNavigateToMoniker	Executes a hyperlink jump to a new document or object represented as a moniker
HlinkGoBack	Executes a hyperlink jump backwards within the navigation stack
HlinkGoForward	Executes a hyperlink jump forwards within the navigation stack

Function	Description
URLOpenStream	Creates a push-type stream object from a URL
URLOpenBlockingStream	Creates a blocking-type stream object from a URL
URLDownloadToFile	Downloads bits from the Internet and saves them to a file
URLOpenPullStream	Creates a pull-type stream object from a URL
URLOpenHttpStream	Advanced function for doing more sophisticated HTTP and FTP downloads, such as performing an HTTP POST

Function	Implementation
URLOpenStream	Mandatory
URLOpenBlockingStream	Optional
URLDownloadToFile	Optional
URLOpenPullStream	Mandatory
URLOpenHttpStream	Optional

Member	Description
ULONG ulSize	Size of this structure.
LPUNKNOWN punkCaller	Pointer to the controlling IUnknown of the calling ActiveX component (if the caller is an ActiveX component). If the caller is not an ActiveX component, this value may be set to NULL. Otherwise, the caller is a COM object that is contained in another component (such as an ActiveX control in the context of an HTML page). The argument represents the outermost IUnknown of the calling component. The function will attempt the download in the context of the ActiveX client framework and allow the caller's container to receive callbacks on the progress of the download.
LPCTSTR szURL	URL to be downloaded.
LPCTSTR szVerb	GET, PUT, POST, or a custom verb understood by the server. If NULL, GET is assumed.
LPCTSTR szHeaders	HTTP headers to use during connection to server. Can be NULL.
LPBYTE szPostData	Additional data to send after the headers. Typically this will be a POST data arguments. Can be NULL.
ULONG ulPostDataLen	Size of szPostData. Must not be 0 if szPostData is not NULL.
ULONG fURLEncode	Flags with either the UOS_URLENCODPOSTDATA, UOS_URLENCODEURL, or can be NULL. The two flags can be combined by a bitwise OR.
ULONG ulMode	Can be one of UOSM_PUSH, UOSM_PULL, UOS_BLOCK, or UOS_FILE. Each of these maps to one of the functions above and makes this function's programming model fit the corresponding function.
LPCTSTR szFileName	Name of the local file to write URL data to if ulMode is UOS_FILE. Otherwise, must be NULL.
LPSTREAM *ppStream	Pointer to IStream pointer if ulMode is UOS_BLOCK. Otherwise, must be NULL.
LPBINDSTATUSCALLBACK lpbscb	Pointer to IBindStatusCallback interface. This interface and the caller's programming model responsibility depend on the ulMode flag above. The function will behave exactly like the corresponding UOS functions above, depending on the flag settings.