Retrieving Conversation text from Instant Messengers - Part I

Environment: VC6,Win 95/98/Me/NT/2000/XP

In this two-article series, I will show you how to retrieve conversation text from two most popular Instant Messengers (MSN and Yahoo). In the first article, we will talk about MSN Messenger. In the second article, we will discuss Yahoo Messenger. So without wasting any time, let's explore MSN Messenger now.

In MSN Messenger, the window class of the window that contains conversation text is 'RichEdit20W' for Windows NT/2K and 'RichEdit20A' for Windows 95/98. These classes support copying their content to the Clipboard by sending WM_COPY a message. Because the Clipboard is available to all the applications in Windows, if some text is copied from an application, it's available to all Windows applications. So, to retrieve text from a MSN Conversation window, simply copy the text from the MSN Conversation window to the Clipboard and paste it into your application. Simple, isn't it? But, sending the WM_COPY message to this window requires HWND of the 'RichEdit20W' Windows class window.

To get the HWND, first we need to check whether there is a MSN Conversation window open. This can be done by using the EnumWindows() API. If it's open, get its HWND and check its child windows to find a window having the window class 'RichEdit20W' or 'RichEdit20A'; this can be done by using the EnumChildWindows() API. After getting the HWND of the conversation text window, we need to send WM_COPY a message. But, sending WM_COPY a message alone will be of no use if we don't select all the text in this window, I mean simulating 'Ctrl+A'. So, in total we need to send three window messages to the conversation window. The first will select all the text in the conversation window by sending EM_SETSEL message with 0 for WPARAM and -1 for LPARAM; the second will copy the selected text in the Clipboard by sending WM_COPY a message and third will deselect the selected text by sending EM_SETSEL a message with -1 for WPARAM and 0 for the LPARAM value. This will be clear from the code snippet given below...

void CMSNChatTextDlg::OnGetnow()
{
  if (! EnumWindows((WNDENUMPROC )EnumWindowsProc,0))
     return;
}

BOOL CALLBACK CMSNChatTextDlg::EnumWindowsProc(HWND hwnd,
                                               LPARAM lParam)
{
  TCHAR buff[1000];
  int buffsize=100;
  HWND hMSNWnd;
  hMSNWnd=NULL;
   
  ::GetWindowText(hwnd,buff,buffsize);
  if (strlen(buff)<1)
    return TRUE;

  string strTemp(buff);

  //CHECK for MSN MESSENGER CHAT WINDOW
  string::size_type pos=0;
  pos=strTemp.rfind("- Conversation",strTemp.length());
  if (pos!=-1)
    EnumChildWindows(hwnd,ChildWndProc,0);

  return TRUE;
}
BOOL CALLBACK CMSNChatTextDlg::ChildWndProc(HWND hwnd,
                                            LPARAM lParam)
{
  static int i=0;
  LPTSTR    lptstr; 
  HGLOBAL   hglb; 
  char wndowclass[CLASS_SIZE];

  if (GetClassName(hwnd,wndowclass,CLASS_SIZE)==0)
    return TRUE;

  string strTemp(wndowclass);
  if ((strTemp==string("RichEdit20W")) ||
      (strTemp==string("RichEdit20A")))
  {
    ::SendMessage(hwnd,EM_SETSEL,0,-1); //start selecting
    ::SendMessage(hwnd,WM_COPY,0,0);
    ::SendMessage(hwnd,EM_SETSEL,-1,0); //end selecting 

    if (!IsClipboardFormatAvailable(CF_TEXT))
       return TRUE;

    if (! ::OpenClipboard(NULL))
      return TRUE;

    hglb = GetClipboardData(CF_TEXT);
    if (hglb != NULL)
    {
      lptstr = (LPTSTR)GlobalLock(hglb);
      GlobalUnlock(hglb);
      EmptyClipboard();
      CloseClipboard();
      
      pChatText->SetWindowText(lptstr);

      return FALSE;
    }
  }
  return TRUE;
}

This gives us the opportunity to make some fantastic SPYING applications that can e-mail MSN conversations of someone to you or whatever you can think of!

In my next article, we will discuss how the same thing can be done with Yahoo Messenger. Remember, WM_COPY messages do not work in Yahoo. We need to put in some extra effort to accomplish this.

Downloads

Download demo project - 4.50 Kb
Download source - 28.3 Kb