The Internet Encyclopedia (Volume 3)

P1: 50

Mayfield WL040/Bidgoli-Vol III-Ch-52 June 23, 2003 16:35 Char Count= 0

WININETCLIENTPROGRAMMING 643

Figure 6: The MFCServer app window.

(4) // Retrieve view ptr so messages

can be displayed.

(5) CWnd *pView = CWnd::FromHandle((HWND)

pParam);

(6)

(7) // Attach the global socket handle

to the local

(8) // server socket object.

(9) serverSock.Attach(hSocket);

(10)

(11) // Create a socket file and a

loading archive.

(12) CSocketFile sockFile(&serverSock);

(13) CArchive archiveRecv(&sockFile,

CArchive::load);

(14)

(15) // Retrieve the time repeatedly

until the server

(16) // connection terminates.

(17) TRY {

(20) char buffer[64];

(18) while (1) {

(19) // Retrieve the time from the

server.

(21) sockFile.Read(buffer, 64);

(22) // Display the string in the view.

(23) pView->SetWindowText(buffer);

(24) }

(25) }

(26) CATCH (CFileException, pEx) {

(27) // Communication was lost

with the server;

(28) // close the server socket.

(29) serverSock.Close();

(30) }

(31) END_CATCH

(32)

(33) // Return success code.

(34) return 0;

(35) }

The important differences between this function and

ServerThreadProcseen earlier are in lines 21 and 23 of

ClientThreadProc. The loop body reads a string from

the server connection and then displays it in the view win-

dow.

Final Changes

Only one global variable is needed to pass socket handle

information betweenOnInitialUpdateandServer-

ThreadProc. Insert the following statement after the

#include statements inMFCClientView.cpp: SOCKET

hSocket;

Build the Project and Test the Client–Server

Application

Build the client project. To test the application, first

start the server program namedMFCServer.exe,which

is found in theDebugdirectory of the server project.

Then start one or more copies of the client program

namedMFCClient.exe,which is found in theDebug

directory of the client project. One should see the num-

ber of clients displayed in the server window, as shown

in Figure 6, and the current time—updated once per

second—displayed in each client window, as shown in

Figure 7.

WININET CLIENT PROGRAMMING

An Alternative to WinSock?

WinInet (Win32 Internet) is an Internet API from

Microsoft written specifically for their Windows operating

Figure 7: The MFCClient app window.