Re: Passing a GUI handle to a socket and Postmessage back to GUI

From:

"KW" <KW@there.com>

Newsgroups:

microsoft.public.vc.mfc

Date:

Wed, 18 Mar 2009 11:41:19 -0400

Message-ID:

<eiAPN#9pJHA.5332@TK2MSFTNGP03.phx.gbl>

I have more questions for those who can help.

There will be approximately 12 clients connecting to my server.
The traffic on these connections will be VERY low.

When I call create(portnum), all clients connect to this port. I would like
to keep track of which station is actually connected at any given time. I
know I can use GetPeerName() to get the IP of the connected client (which
would ID the client), but I wonder if I may need to use a different port
number if the client IP was changed without my knowledge.

If the IP changed, the client would still connect to port nnnn, which would
still allow me to ID the client - I think.
In this scenario, would it be better for me to listen on different ports
for each client?

Also, the server might need to respond to application level keep alives
(adding to a configuration file: Keepalives TRUE/FALSE). I already have this
in place. I just "ACK" the "KA" when received. My question involves the
scenario where a keepalive is not received within a given amount of time (NO
FD_CLOSE). I would need to close a specific connection and begin listening
again. Setting up a timer for each connection is problematic because the is
no CWnd in my CAsyncSocket class.

Will the connection eventually "die" if there is an abnormal disconnect?

I don't believe SetSockOpt(SO_KEEPALIVE,...) would help me, would it? I am
not sure if the "clients" have this turned on.

Is there a better way to set up a KeepAlive timer for each connection?

I'm sure many have dealt with these same problems, but I have not come to a
conclusion on the best way to proceed. Any help you can provide?

Thanks,
KW

"KW" <KW@there.com> wrote in message
news:OZcqxPmoJHA.1252@TK2MSFTNGP03.phx.gbl...

I have a MDI application with several child windows and a TCPIP server. I
want to pass the handle (of one child) to a server socket class so it can
post a message to the child window when data is received. When the data is
received by the child window, a listbox will display the data.

I have it working, but I wonder if there is a better way of passing (or
getting) the handle. I have to pass it twice to get it into the
OnReceive() Handler of CServer.cpp.

// Click a button and start the listener - couldn't get it to work in
constructor (handle not created yet?) - "SocketWindow" is UI class
void SocketWindow::OnButton1()
{
   sockServ = new MySocket(CWnd::m_hWnd); //Is this the best way to
get/pass the handle?
   sockServ->Create(1001);
   sockServ->Listen();
}

void SocketWindow::OnSockMSG(UINT wParam, long lParam)
{
   CString * ptr = (CString *)wParam;

   m_ListBoxAdder.AddString(*ptr);

   delete(ptr);
}

// These 4 lines are from MySocket.h
public:
MySocket(HWND);
virtual ~MySocket();
CServer client;
HWND ChildWindowHandle;

// Constructor MySocket.cpp
MySocket::MySocket(HWND MyHandle)
{
    ChildWindowHandle = MyHandle;
}

// MySocket.cpp
void MySocket::OnAccept(int nErrorCode)
{
    if (nErrorCode == 0)
    {
          this->Accept(client);

           // IS THIS A PROBLEM? "client" is declared in CServer.h
           client.HandleToChld = ChildWindowHandle ;
     }
}

// CServer.cpp
void CServer::OnReceive(int nErrorCode)
{
    char buffer[1024] ;
    memset(buffer, 0, sizeof(buffer)) ;
    this->Receive(buffer, sizeof(buffer)) ;

    CString result(buffer);

    CString * ptrToData = new CString(result) ;

    // "WM_SCKTMSG_RECV" is defined in stdAfx.h (#define WM_SCKTMSG_RECV
WM_USER + 3), executes "OnSockMSG" above

    ::PostMessage(HandleToChld, WM_SCKTMSG_RECV, (WPARAM)ptrToData,
(LPARAM)0);

    //CAsyncSocket::OnReceive(nErrorCode);
}

Although this code currently works, it does not feel right (passing the
handle in the constructor??).
There has to be a better way of doing this. Any suggestions?

Thanks,
KW