Platinum Edition Using HTML 4, XML, and Java 1.2
(Publisher: Macmillan Computer Publishing)
Author(s): Eric Ladd
ISBN: 078971759x
Publication Date: 11/01/98

LastHit

LastHit is yet another Windows NT SSI program. It tracks visitor information (date, time, IP number, and browser type). Like FirstHit, LastHit uses the same Registry scheme as HitCount or HitCntth, but it stores its information in its own key. You have to set the (default) page name here, too, if it’s something other than Default.htm. The proper key is

HKEY_LOCAL_MACHINE
    \Software
        \Greyware
            \LastHit
                \Pages

LastHit isn’t actually related to HitCount or FirstHit, other than by its common code and its nature as an SSI program. LastHit tracks and displays information about the last visitor to a page. Each time the page is hit, LastHit displays the information from the previous hit and then writes down information about the current caller for display next time.

The source code for LastHit is a little more complicated than FirstHit’s, as Listing 32.8 shows. It uses a subroutine. If nothing else, these programs should demonstrate how easily SSI lets you create dynamic documents. There’s no rocket science here.

Listing 32.8 lasthit.c—Provides Information on the Last Person Who Accessed the Page

// LASTHIT.C
// This SSI program tracks visitors to a page, remembering
// the most recent for display.

#include <windows.h>
#include <stdio.h>
#define      ERROR_CANT_CREATE “LastHit:  Cannot open/create
⇒registry key.”
#define  ERROR_CANT_UPDATE “LastHit:  Cannot update registry key.”
#define  LASTHIT “Software\\Greyware\\LastHit\\Pages”

// This subroutine builds the info string about the
// current caller.  Hence the name.  It uses a pointer
// to a buffer owned by the calling routine for output,
// and gets its information from the standard SSI
// environment variables.  Since “standard” is almost
// meaningless when it comes to SSI, the program
// gracefully skips anything it can’t find.

void BuildInfo(char * szOut) {
     SYSTEMTIME   st;
     char         szTmp[512];
     char         *p;

     szOut[0]=’\0';

     GetLocalTime(&st);
     GetDateFormat(0, DATE_LONGDATE, &st, NULL, szTmp, 511);
     sprintf(szOut,
          “Last access on %s at %02d:%02d:%02d”,
          szTmp,
          st.wHour,
          st.wMinute,
          st.wSecond);

     p = getenv(“REMOTE_ADDR”);
     if (p!=NULL) {
          szTmp[0] = ‘\0’;
          sprintf(szTmp,“<br>Caller from %s”,p);
          if (szTmp[0] != ‘\0’) strcat(szOut,szTmp);
     }
     p = getenv(“REMOTE_HOST”);
     if (p!=NULL) {
          szTmp[0] = ‘\0’;
          sprintf(szTmp,“ (%s)”,p);
          if (szTmp[0] != ‘\0’) strcat(szOut,szTmp);
     }
     p = getenv(“HTTP_USER_AGENT”);
     if (p!=NULL) {
          szTmp[0] = ‘\0’;
          sprintf(szTmp,“<br>Using %s”,p);
          if (szTmp[0] != ‘\0’) strcat(szOut,szTmp);
     }
}

void main(int argc, char * argv[]) {
     char     szOldInfo[512];
     char     szNewInfo[512];
     char     szDefPage[80];
     char     *p;
     char     *PageName;     // pointer to this page’s name
     long     dwLength=511;  // length of temporary buffer
     long     dwType;        // registry value type code
     long     dwRetCode;     // generic return code from API
     HKEY     hKey;          // registry key handle

     // Determine where to get the page name.  A command-
     // line argument overrides the SCRIPT_NAME variable.

     if ((argc==2) && ((*argv[1]==‘/’) | (*argv[1]==‘\\’)))
          PageName = argv[1];
     else
          PageName = getenv(“SCRIPT_NAME”);

     // If invoked from without SCRIPT_NAME or args, die
     if (PageName==NULL)
     {
          printf(“LastHit 1.0.b.960121\n”
                 “Copyright (c) 1995,96 Greyware ”
                 “Automation Products\n\n”
                 “Documentation available online from ”
                 “Greyware’s Web server:\n”
                 <“http://www.greyware.com/”>
                 “greyware/software/freeware.htp\n\n”);
     }
     else
     {

          // Build info for next call

          BuildInfo(szNewInfo);

          // Open the registry key

          dwRetCode = RegOpenKeyEx (
               HKEY_LOCAL_MACHINE,
               LASTHIT,
               0,
               KEY_EXECUTE,
               &hKey);

          // If open failed because key doesn’t exist,
          //create it

          if ((dwRetCode==ERROR_BADDB)
               || (dwRetCode==ERROR_BADKEY)
               || (dwRetCode==ERROR_FILE_NOT_FOUND))
               dwRetCode = RegCreateKey(
                    HKEY_LOCAL_MACHINE,
                    LASTHIT,
                    &hKey);

          // If couldn’t open or create, die

          if (dwRetCode != ERROR_SUCCESS) {
               printf (ERROR_CANT_CREATE);
          } else {

               // Get the default page name
               dwLength = sizeof(szDefPage);
               dwRetCode = RegQueryValueEx (
                    hKey,
                    “(default)”,
                    0,
                    &dwType,
                    szDefPage,
                    &dwLength);
               if ((dwRetCode == ERROR_SUCCESS)
                    && (dwType == REG_SZ)
                    && (dwLength > 0)) {
                    szDefPage[dwLength] = ‘\0’;
               } else {
                    strcpy(szDefPage,“default.htm”);
               }

               // If current page uses default page name,
               // strip the page name
               _strlwr(PageName);
               p = strrchr(PageName,‘/’);
               if (p==NULL) p = strrchr(PageName,‘\\’);
               if (p) {
                    p++;
                    if (stricmp(p,szDefPage)==0) *p = ‘\0’;
               }

               // Get this page’s information
               dwLength = sizeof(szOldInfo);
               dwRetCode = RegQueryValueEx (
                    hKey,
                    PageName,
                    0,
                    &dwType,
                    szOldInfo,
                    &dwLength);
               if ((dwRetCode == ERROR_SUCCESS)
                    && (dwType == REG_SZ)
                    && (dwLength >0)) {
                    szOldInfo[dwLength] = ‘\0’;
               } else {
                    strcpy (szOldInfo, szNewInfo);
               }

               // Close the registry key
               dwRetCode = RegCloseKey(hKey);

               // Print this page’s info
               printf(“%s”,szOldInfo);


               // Write the new value back to the registry
               dwRetCode = RegOpenKeyEx (
                    HKEY_LOCAL_MACHINE,
                    LASTHIT,
                    0,
                    KEY_SET_VALUE,
                    &hKey);
               if (dwRetCode==ERROR_SUCCESS) {
                    dwRetCode = RegSetValueEx(
                         hKey,
                         PageName,
                         0,
                         REG_SZ,
                         szNewInfo,
                         strlen(szNewInfo));
                    dwRetCode = RegCloseKey(hKey);
               } else {
                    printf(ERROR_CANT_UPDATE);
               }
          }
     }
     fflush(stdout);
     return;
}