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.c
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.c
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.c
/*
* Copyright (c) Mbedthis Software LLC, 2003-2004. All Rights Reserved.
*/
/*!
* @file winEventLoop.c
* @brief Embed the AppWeb server in a windows single-threaded program
* using the windows message event mechanism. NOTE: this will
* work in a multi-threaded 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 */
/************************** Forward Declarations **********************/
static int findInstance();
static int initWindow();
static void eventLoop();
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; /* For the http service inside our app */
MaServer *server; /* For a HTTP server */
/*
* Initialize the run-time and give our app a name
* "winEventLoop"
*/
mprCreateMpr("winEventLoop");
/*
* Do the following two statements only if you want debug trace
*/
mprAddLogFileListener();
mprSetLogSpec("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()
*/
mprSetAsyncSelectMode(MPR_ASYNC_SELECT);
/*
* Start run-time services
*/
mprStartMpr(0);
/*
* Create the HTTP and server objects. Give the server a name
* "default" and define "." as the default serverRoot, ie. the
* directory with the server configuration files.
*/
http = maCreateHttp();
server = maCreateServer(http, "default", ".");
/*
* Configure the server based on the directives in
* winEventLoop.conf.
*/
if (maConfigureServer(server, "winEventLoop.conf", 0) < 0) {
fprintf(stderr,
"Can't configure the server. Error on line %d\n",
maGetConfigErrorLine(server));
exit(2);
}
/*
* Start serving pages. After this we are live.
*/
if (maStartServers(http) < 0) {
fprintf(stderr, "Can't start the server\n");
exit(2);
}
/*
* Service events. This call will block until the server is exited
* Call mprTerminate() at any time to instruct the server to exit.
*/
eventLoop();
/*
* Stop all HTTP services
*/
maStopServers(http);
/*
* Delete the server and http objects
*/
maDeleteServer(server);
maDeleteHttp(http);
/*
* Stop and delete the run-time services
*/
mprStopMpr();
mprDeleteMpr();
return 0;
}
/**********************************************************************/
/*
* Sample main event loop using select. This demonstrates how to
* integrate AppWeb with your applications event loop using select()
*/
static void eventLoop()
{
MSG msg;
int timeout, till;
/*
* We will nap for 50 milliseconds to avoid busy waiting
*/
timeout = 50;
while (!mprIsExiting()) {
if (mprRunTimers() > 0) {
till = 0;
} else {
till = mprGetIdleTime();
}
/*
* This will run tasks if maxThreads == 0 (single threaded).
* If multithreaded, the thread pool will run tasks
*/
if (mprRunTasks() > 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;
}
mprSetHwnd(appHwnd);
mprSetSocketHwnd(appHwnd);
mprSetSocketMessage(SOCKET_MESSAGE);
/*
* Uncomment these lines 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:
mprTerminate(1);
break;
case SOCKET_MESSAGE:
sock = wp;
winMask = LOWORD(lp);
mprServiceWinIO(sock, winMask);
break;
default:
return DefWindowProc(hwnd, msg, wp, lp);
}
return 0;
}
/**********************************************************************/
#endif /* WIN */