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C/C++ Source or Header  |  1997-10-25  |  7KB  |  323 lines
  1. /*++
  2.  
  3. Copyright (c) 1997  Microsoft Corporation
  4.  
  5. Module Name: KeepAliveP.c
  6.  
  7. Abstract:
  8.  
  9.       Sample ISAPI Extension demonstrating Keep-Alive with a thread pool.
  10.  
  11. --*/
  12.  
  13. #define WIN32_LEAN_AND_MEAN
  14. #include <windows.h>
  15. #include <httpext.h>
  16. #include <stdio.h>
  17. #include "threadpool.h"
  18.  
  19. BOOL WINAPI 
  20. DllMain( 
  21.     IN HINSTANCE hinstDll, 
  22.     IN DWORD fdwReason, 
  23.     IN LPVOID lpvContext
  24. ) 
  25. /*++
  26.  
  27. Purpose:
  28.     
  29.     Initialize the thread pool when the DLL is loaded by IIS.
  30.  
  31. Arguments:
  32.  
  33.     hinstDLL - DLL instance handle
  34.     fdwReason - notification code
  35.     lpdvContext - reserved
  36.  
  37. Returns:
  38.  
  39.     TRUE if notification was successfully processed by the DLL
  40.     FALSE to indicate a failure
  41.  
  42. --*/
  43. {
  44.     BOOL fReturn = TRUE;
  45.  
  46.     switch ( fdwReason ) {
  47.  
  48.     case DLL_PROCESS_ATTACH:
  49.         fReturn = InitThreadPool( );
  50.         break;
  51.     }
  52.  
  53.     return fReturn;
  54. }
  55.  
  56.  
  57. BOOL WINAPI 
  58. GetExtensionVersion( 
  59.     OUT HSE_VERSION_INFO * pVer
  60. )
  61. /*++
  62.  
  63. Purpose:
  64.  
  65.     This is required ISAPI Extension DLL entry point.
  66.  
  67. Arguments:
  68.  
  69.     pVer - poins to extension version info structure 
  70.  
  71. Returns:
  72.  
  73.     always returns TRUE
  74.  
  75. --*/
  76. {
  77.     pVer->dwExtensionVersion = MAKELONG( HSE_VERSION_MINOR, HSE_VERSION_MAJOR );
  78.     lstrcpyn( 
  79.         pVer->lpszExtensionDesc, 
  80.         "ISAPI Keep-Alive with Thread Pool Extension Sample",
  81.         HSE_MAX_EXT_DLL_NAME_LEN );
  82.  
  83.     return TRUE;
  84. }
  85.  
  86.  
  87. DWORD WINAPI 
  88. HttpExtensionProc( 
  89.     IN EXTENSION_CONTROL_BLOCK * pECB
  90. )
  91. /*++
  92.  
  93. Purpose:
  94.     Demonstrate usage of persistent connections serviced by a thread pool.
  95.  
  96. Arguments:
  97.  
  98.     pECB - points to the extension control block
  99.  
  100. Returns:
  101.     
  102.     HSE_STATUS_PENDING if request was successfully queued 
  103.     HSE_SUCCESS_AND_KEEP_CONN if request was served immediately
  104.         (presumably because the queue was full)
  105.  
  106. --*/
  107. {
  108.     DWORD dwSize;
  109.     HSE_SEND_HEADER_EX_INFO HeaderExInfo;
  110.  
  111.     char szHeader[] = 
  112.         "Connection: Keep-Alive\r\n"
  113.         "Content-Length: %lu\r\n"
  114.         "Content-type: text/html\r\n\r\n";
  115.  
  116.     char szBusyMessage[] = 
  117.         "<html> <form method=get action=KeepAliveP.dll> <input type=submit> "
  118.         "<br>pECB->ConnID=%lu  <br>Server was too busy. </form></html>";
  119.  
  120.     char szBuffer[4096];
  121.     char szBuffer2[4096];
  122.  
  123.     EnterCriticalSection( &csQueueLock );
  124.  
  125.     if ( !AddWorkQueueEntry( pECB ) ) {
  126.  
  127.         //
  128.         // if ECB could not be assigned
  129.         //
  130.  
  131.         LeaveCriticalSection( &csQueueLock );
  132.  
  133.         sprintf( szBuffer2, szBusyMessage, pECB->ConnID );
  134.  
  135.         //
  136.         // Send outgoing header
  137.         //
  138.  
  139.         sprintf( szBuffer, szHeader, strlen( szBuffer2 ) );
  140.  
  141.         HeaderExInfo.pszHeader = szBuffer;
  142.         HeaderExInfo.cchHeader = strlen( szBuffer );
  143.         HeaderExInfo.pszStatus = "200 OK";
  144.         HeaderExInfo.cchStatus = strlen( HeaderExInfo.pszStatus );
  145.         HeaderExInfo.fKeepConn = TRUE;
  146.  
  147.  
  148.         pECB->ServerSupportFunction( 
  149.             pECB->ConnID, 
  150.             HSE_REQ_SEND_RESPONSE_HEADER_EX,
  151.             &HeaderExInfo,
  152.             NULL,
  153.             NULL
  154.             );
  155.  
  156.         //
  157.         // Send content
  158.         //
  159.  
  160.         dwSize = strlen( szBuffer2 );
  161.         pECB->WriteClient( pECB->ConnID, szBuffer2, &dwSize, 0 );
  162.  
  163.         return HSE_STATUS_SUCCESS_AND_KEEP_CONN;
  164.  
  165.     } else {
  166.  
  167.         //
  168.         // release 1 thread from the pool
  169.         //
  170.  
  171.         ReleaseSemaphore( hWorkSem, 1, NULL );
  172.  
  173.         LeaveCriticalSection( &csQueueLock );
  174.     }
  175.  
  176.     return HSE_STATUS_PENDING;
  177. }
  178.  
  179.  
  180. BOOL WINAPI
  181. TerminateExtension( 
  182.     IN DWORD dwFlags 
  183. )
  184. /*++
  185.  
  186. Routine Description:
  187.  
  188.     This function is called when the WWW service is shutdown
  189.  
  190. Arguments:
  191.  
  192.     dwFlags - HSE_TERM_ADVISORY_UNLOAD or HSE_TERM_MUST_UNLOAD
  193.  
  194. Return Value:
  195.  
  196.     TRUE if extension is ready to be unloaded,
  197.     FALSE otherwise
  198.  
  199. --*/
  200. {
  201.     return TRUE;
  202. }
  203.  
  204.  
  205.  
  206. DWORD WINAPI 
  207. WorkerFunction( 
  208.     IN LPVOID pvThreadNum
  209. )
  210. /*++
  211.  
  212. Purpose:
  213.     
  214.     Worker thread function - simulates extended processing
  215.     of the HTTP request
  216.  
  217. Arguments:
  218.  
  219.     pvThreadNum - thread number
  220.  
  221. Returns:
  222.     
  223.     alsways returns 0
  224.  
  225. --*/
  226. {
  227.     EXTENSION_CONTROL_BLOCK *pECB;
  228.     DWORD dwRet, dwState, dwSize, dwThreadNum;
  229.     HSE_SEND_HEADER_EX_INFO HeaderExInfo;
  230.  
  231.     //This header will be filled in with the content length
  232.     char szHeader[] = 
  233.         "Connection: Keep-Alive\r\nContent-Length: %lu\r\n"
  234.         "Content-type: text/html\r\n\r\n";
  235.  
  236.     char szContent[] = 
  237.         "<html> <form method=get action=KeepAliveP.dll><input type=submit> " 
  238.         "<br>pECB->ConnID=%lu  <br>dwThreadNum=%lu</form></html>";
  239.  
  240.     char szBuffer[4096];
  241.     char szBuffer2[4096];
  242.  
  243.     dwThreadNum = ( DWORD ) pvThreadNum;
  244.  
  245.     while ( TRUE ) {
  246.  
  247.         dwRet = WaitForSingleObject( hWorkSem, INFINITE );
  248.         if ( dwRet == WAIT_OBJECT_0 ) {
  249.  
  250.             EnterCriticalSection( &csQueueLock );
  251.  
  252.             if ( GetWorkQueueEntry( &pECB ) ) {    
  253.                 
  254.                 //
  255.                 // Found work to do
  256.                 //
  257.  
  258.                 LeaveCriticalSection( &csQueueLock );
  259.  
  260.                 sprintf( szBuffer2, szContent, pECB->ConnID, dwThreadNum );
  261.  
  262.                 // Send outgoing header
  263.                 sprintf( szBuffer, szHeader, strlen( szBuffer2 ) );
  264.  
  265.                 HeaderExInfo.pszHeader = szBuffer;
  266.                 HeaderExInfo.cchHeader = strlen( szBuffer );
  267.                 HeaderExInfo.pszStatus = "200 OK";
  268.                 HeaderExInfo.cchStatus = strlen( HeaderExInfo.pszStatus );
  269.                 HeaderExInfo.fKeepConn = TRUE;
  270.  
  271.                 pECB->ServerSupportFunction( 
  272.                     pECB->ConnID, 
  273.                     HSE_REQ_SEND_RESPONSE_HEADER_EX,
  274.                     &HeaderExInfo, 
  275.                     NULL,
  276.                     NULL
  277.                     );
  278.  
  279.                 //
  280.                 // Simulate extended processing
  281.                 //
  282.  
  283.                 Sleep( 3000 );
  284.  
  285.                 //
  286.                 // Send content
  287.                 //
  288.  
  289.                 dwSize = strlen( szBuffer2 );
  290.                 pECB->WriteClient( pECB->ConnID, szBuffer2, &dwSize, 0 );
  291.  
  292.                 //
  293.                 // Tell IIS to keep the connection open
  294.                 //
  295.  
  296.                 dwState = HSE_STATUS_SUCCESS_AND_KEEP_CONN;
  297.  
  298.                 pECB->ServerSupportFunction( 
  299.                     pECB->ConnID, 
  300.                     HSE_REQ_DONE_WITH_SESSION, 
  301.                     &dwState, 
  302.                     NULL, 
  303.                     0 
  304.                     );
  305.  
  306.             } else {            
  307.  
  308.                 //
  309.                 // No item found is unexpected condition - exit thread
  310.                 //
  311.  
  312.                 LeaveCriticalSection( &csQueueLock );
  313.                 ExitThread( 0 );
  314.             }
  315.  
  316.         } else {
  317.             break;
  318.         }
  319.     }
  320.  
  321.     return 0;
  322. }
  323.