Keep-Alive Sample

/*
	Copyright (c) 1997-2002  Microsoft Corporation

	Module Name:    
	
		KeepAlive.c

	Abstract:

		 Sample ISAPI Extension demonstrating Keep-Alive.
*/

#define WIN32_LEAN_AND_MEAN
#include <windows.h>
#include <httpext.h>
#include <stdio.h>

/*
	Description:

		This is required ISAPI Extension DLL entry point.

	Arguments:

		pVer - poins to extension version info structure 

	Returns:

		always returns TRUE 
*/


BOOL WINAPI GetExtensionVersion(OUT HSE_VERSION_INFO *pVer)
{
	char const szSamp[] = "ISAPI Keep-Alive Extension Sample";

	pVer->dwExtensionVersion = MAKELONG(HSE_VERSION_MINOR, HSE_VERSION_MAJOR);

	strncpy_s(pVer->lpszExtensionDesc, strlen(szSamp), szSamp, HSE_MAX_EXT_DLL_NAME_LEN);

	return TRUE;
}

/*
	Description:
		
		Demonstrate persistent connection from ISAPI extension DLL.

	Arguments:

		pECB - pointer to the extenstion control block 

	Returns:

		HSE_STATUS_SUCCESS_AND_KEEP_CONN
*/

DWORD WINAPI HttpExtensionProc(IN EXTENSION_CONTROL_BLOCK *pECB)
{
	/*
		Use the "Connection: Keep-Alive" header to keep the connection open;
		also, the "Content-Length:" header is required, so that the client knows when
		the server has finished. 
	*/

	char szHeader[] = 
			"Connection: Keep-Alive\r\n"
			"Content-Length: %lu\r\n"
			"Content-type: text/html\r\n\r\n";

	char szContent[] = 
			"<html> <form method=get action=\\scripts\\KeepAlive.dll>"
			"<h1>Keep-Alive Sample</h1><hr>"
			"<input type=submit value=\"Send Request\"></form></html>";

	char szBuffer[4096];
	DWORD dwSize;
	HSE_SEND_HEADER_EX_INFO HeaderExInfo;

	/* Send outgoing header with exact content length */

	sprintf_s(szBuffer, strlen(szBuffer), szHeader, strlen(szContent));
	HeaderExInfo.pszHeader = szBuffer;
	HeaderExInfo.cchHeader = strlen(szBuffer);
	HeaderExInfo.pszStatus = "200 OK";
	HeaderExInfo.cchStatus = strlen(HeaderExInfo.pszStatus);
	HeaderExInfo.fKeepConn = TRUE;

	pECB->ServerSupportFunction(pECB, HSE_REQ_SEND_RESPONSE_HEADER_EX, &HeaderExInfo, NULL, NULL);

	/* Send content */

	dwSize = strlen(szContent);

	pECB->WriteClient(pECB, szContent, &dwSize, HSE_IO_SYNC);

	/* This return code tells IIS not to close the socket connection. */

	return HSE_STATUS_SUCCESS_AND_KEEP_CONN;
}

/*
	Description:

		This is optional ISAPI extension DLL entry point. If present, it will be
		called before unloading the DLL, giving it a chance to perform any 
		shutdown procedures.
    
	Arguments:
    
		dwFlags - HSE_TERM_ADVISORY_UNLOAD or HSE_TERM_MUST_UNLOAD

	Return Value:

		TRUE if extension is ready to be unloaded,
		FALSE otherwise
*/

BOOL WINAPI TerminateExtension(IN DWORD dwFlags)
{
    return TRUE;
}