Windows Event Loop Sample in C++
The Windows Event Loop sample demonstrates how to add HTTP server functionality to your C application and use a Windows event loop to wait for events.
The sample is a single-threaded main program that listens on port 8888 for HTTP requests. You can easily make it multithreaded by changing the value of the ThreadLimit directive in the configuration file.
See also the equivalent C winEventLoop sample.
winEventLoop.conf
winEventLoop.cpp
This configuration file loads the embedded JavaScript module and the embedded server pages and embedded gateway interface, and static content handlers. It is configured to run single-threaded. It assumes that the sample is being run from the samples C++/winEventLoop directory and so the module paths are relative to the lib directory in the samples source tree. Modify these module paths to suit your installation.
You should modify the DocumentRoot and Listen directives to suit your application's needs.
The sample is a single-threaded main program that listens on port 8888 for HTTP requests. You can easily make it multithreaded by changing the value of the ThreadLimit directive in the configuration file.
See also the equivalent C winEventLoop sample.
Files
winEventLoop.confwinEventLoop.cpp
Configuration File
winEventLoop.conf
DocumentRoot "."
Listen 8888
ThreadLimit 0
LoadModule ejs ../../../lib/libejsModule
LoadModule egi ../../../lib/libegiHandler
LoadModule esp ../../../lib/libespHandler
LoadModule static ../../../lib/libcopyHandler
AddHandler egiHandler .egi
AddHandler espHandler ESP
AddHandler copyHandler
This configuration file loads the embedded JavaScript module and the embedded server pages and embedded gateway interface, and static content handlers. It is configured to run single-threaded. It assumes that the sample is being run from the samples C++/winEventLoop directory and so the module paths are relative to the lib directory in the samples source tree. Modify these module paths to suit your installation.
You should modify the DocumentRoot and Listen directives to suit your application's needs.
Source Code
winEventLoop.cpp
//
// Copyright (c) Mbedthis Software LLC, 2003-2004. All Rights Reserved.
//
/// @file winEventLoop.cpp
/// @brief Embed the AppWeb server in a windows single-threaded
/// program using the windows message event mechanism.
/// NOTE: this will work in a multithreaded program as well.
///
#if WIN
/////////////////////////////// Includes ///////////////////////////////
#include "appWeb/appWeb.h"
/////////////////////////////// Defines ////////////////////////////////
#define APP_NAME "winEventLoop"
#define APP_TITLE "Sample Windows Event Loop"
#define SOCKET_MESSAGE WM_USER+32
//////////////////////////////// Locals ////////////////////////////////
static HINSTANCE appInst; // Current application instance
static HWND appHwnd; // Application window handle
static Mpr *mp;
//////////////////////////// Forward Declarations //////////////////////
static void eventLoop();
static int findInstance();
static int initWindow();
static long msgProc(HWND hwnd, uint msg, uint wp, long lp);
/////////////////////////////////// Code ///////////////////////////////
int APIENTRY WinMain(HINSTANCE inst, HINSTANCE junk, char *args,
int junk2)
{
MaHttp *http; // Http service inside our app
MaServer *server; // For the HTTP server
Mpr mpr("winEventLoop"); // Initialize the run time
//
// Do the following two statements only if you want debug trace
//
mp = &mpr;
mpr.addListener(new MprLogToFile());
mpr.setLogSpec("error.log:4");
if (findInstance()) {
mprError(MPR_L, MPR_LOG, "Application is already active");
return FALSE;
}
//
// Create the window object
//
if (initWindow() < 0) {
mprError(MPR_L, MPR_ERROR,
"Can't initialize application Window");
return FALSE;
}
//
// Use windows async select and message dispatcher rather than
// select()
//
mp->setAsyncSelectMode(MPR_ASYNC_SELECT);
//
// Start the Mbedthis Portable Runtime and request single threading
// NOTE: this program can be compiled multi-threaded. If so, change
// the parameter to a "1".
//
mpr.start(0);
//
// Create Http and Server objects for this application. We set the
// ServerName to be "default" and the initial serverRoot to be ".".
// This will be overridden in winEventLoop.conf.
//
http = new MaHttp();
server = new MaServer(http, "default", ".");
//
// Configure the server with the configuration directive file
//
if (server->configure("winEventLoop.conf", 0) < 0) {
mprFprintf(MPR_STDERR,
"Can't configure the server. Error on line %d\n",
server->getLine());
exit(2);
}
//
// Start the server
//
if (http->start() < 0) {
mprFprintf(MPR_STDERR, "Can't start the server\n");
exit(2);
}
//
// Service incoming requests until time to exit.
//
eventLoop();
//
// Orderly shutdown
//
http->stop();
delete server;
delete http;
//
// MPR run-time will automatically stop and be cleaned up
//
return 0;
}
////////////////////////////////////////////////////////////////////////
//
// Sample main event loop. This demonstrates how to integrate Mpr with
// your applications event loop using select()
//
void eventLoop()
{
MSG msg;
int till;
//
// If single threaded or if you desire control over the event
// loop, you should code an event loop similar to that below:
//
while (!mp->isExiting()) {
if (mp->runTimers() > 0) {
till = 0;
} else {
till = mp->getIdleTime();
}
//
// This will run tasks if poolThreads == 0 (single threaded).
// If multithreaded, the thread pool will run tasks
//
if (mp->runTasks() > 0) { // Returns > 0 if more work to do
till = 0; // So don't block in select
}
SetTimer(appHwnd, 0, till, NULL);
//
// Socket events will be serviced in the msgProc
//
if (GetMessage(&msg, NULL, 0, 0) == 0) {
// WM_QUIT received
break;
}
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
////////////////////////////////////////////////////////////////////////
//
// See if an instance of this product is already running
//
static int findInstance()
{
HWND hwnd;
hwnd = FindWindow(APP_NAME, APP_TITLE);
if (hwnd) {
if (IsIconic(hwnd)) {
ShowWindow(hwnd, SW_RESTORE);
}
SetForegroundWindow(hwnd);
return 1;
}
return 0;
}
////////////////////////////////////////////////////////////////////////
//
// Initialize the applications's window
//
static int initWindow()
{
WNDCLASS wc;
int rc;
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = (HINSTANCE) appInst;
wc.hIcon = NULL;
wc.lpfnWndProc = (WNDPROC) msgProc;
wc.lpszMenuName = wc.lpszClassName = APP_NAME;
rc = RegisterClass(&wc);
if (rc == 0) {
mprError(MPR_L, MPR_ERROR, "Can't register windows class");
return -1;
}
appHwnd = CreateWindow(APP_NAME, APP_TITLE, WS_OVERLAPPED,
CW_USEDEFAULT, 0, 0, 0, NULL, NULL, appInst, NULL);
if (! appHwnd) {
mprError(MPR_L, MPR_ERROR, "Can't create window");
return -1;
}
mp->setHwnd(appHwnd);
mp->setSocketHwnd(appHwnd);
mp->setSocketMessage(SOCKET_MESSAGE);
//
// Uncomment these lines if you want to show the window
// (not much help)
//
// ShowWindow(appHwnd, SW_MINIMIZE);
// UpdateWindow(appHwnd);
//
return 0;
}
////////////////////////////////////////////////////////////////////////
//
// Windows message processing loop
//
static long msgProc(HWND hwnd, uint msg, uint wp, long lp)
{
int sock, winMask;
switch (msg) {
case WM_DESTROY:
case WM_QUIT:
mprGetMpr()->terminate(1);
break;
case SOCKET_MESSAGE:
sock = wp;
winMask = LOWORD(lp);
mprGetMpr()->serviceIO(sock, winMask);
break;
default:
return DefWindowProc(hwnd, msg, wp, lp);
}
return 0;
}
////////////////////////////////////////////////////////////////////////
#endif // WIN