#!/usr/local/bin/perl

# This is a companion program to the "counter.xbm" script.  
# When invoked, it responds with some HTML that it builds on
# the fly that give usage statistics.

# This script was written by Michael Morse (mmorse@nsf.gov) at
# the National Science Foundation.  Feel free to modify and use
# it any way you wish.  You will certainly have to modify
# initialize(), since most of the NSF-specific stuff is there.
# Also, createHTML() has some more NSF-specific stuff (like my
# address!), that you'll want to change.

   &initialize;
   &getDate;
   &getNumbers;
   &createHTML;
exit(0);

sub createHTML {
print<<EOMEOM;
Content-type: text/html

<TITLE>Usage Statistics for $forString</TITLE>
<H1>Usage Statistics for $forString</H1>
<HR>
<H2>Numbers That May Interest You</H2>
As of now ($date):
<UL>
<LI>
$theString has been retrieved from the server 
<B>$count</B> 
times since September 13, 1994.
<LI>
A total of 
<B>$hosts</B> 
different computers have retrieved the
Beer Page. 
Since most computers that run WWW clients are single-user, this 
number is pretty close to the number of different users.
<LI>
Your computer has retrieved the Beer Page
<B>$you</B> 
times.
</UL>
<HR>
<H2>How the Numbers are Created</H2>
The "odometer" on the Beer Page is generated by a Perl program that
counts the number of times it is invoked, keeping track, each time,
of the IP address of the client. 
This page is generated by another program (also in Perl) that reads the data
produced by the odometer program.  Actually, the odometer is incremented only
when your browser tries to retrieve the odometer image.  If you're using
a text-mode browser (e.g., Lynx), the counter is NOT incremented.  If you
really want to be counted, 
<A HREF="/cgi-bin/count/text">select this link.</A>
<P>
The odometer counter was adapted from a similar program
used at 
<a href="http://www.larc.nasa.gov/">
NASA Langley Research Center.
</A>
You can also retrieve a copy of 
<A HREF="/cgi/count">the odometer program</A>
or the 
<A HREF="/cgi/stats">the script that produces this page</A>.

<P>Note that in order to use these scripts for your own page, you <B>must</B>
be able to install "CGI" scripts.  The scripts are written in perl, so you 
need to have perl installed, too.
The log files used by the scripts must be readable and writable by the 
user-id used by the HTTP daemon, and so must the directory in which they are
stored.

<HR>
<A HREF="/Beer/">Back to the Beer Page.</A>
EOMEOM
}



sub initialize {
   $port = $ENV{SERVER_PORT};
      $serverRoot = "/www";
      $forString = "the Beer Page";
      $theString = "The Beer Page";
   $counterFile = "$serverRoot/logs/counter.txt";
   $hostsFile = "$serverRoot/logs/counthosts.txt";
   $dbmFile =   "$serverRoot/logs/hosts";
}



sub getNumbers {
   open(COUNTERFILE,"<$counterFile") || die "$0: can\'t open $counterFile: $!\n";
   $count = <COUNTERFILE>;
   chop $count;
   close(COUNTERFILE);
   open(COUNTERFILE,"<$hostsFile") || die "$0: can\'t open $hostsFile: $!\n";
   $hosts = <COUNTERFILE>;
   chop $hosts;
   close(COUNTERFILE);
   
   dbmopen(HOSTS,$dbmFile,0666);
   $who = $ENV{REMOTE_ADDR};
   $you = $HOSTS{$who};
   dbmclose(HOSTS);
   $count =~ s/^0+//;
   $hosts =~ s/^0+//;
   $you =~ s/^0+//;
   
}



sub getDate{
   @month_names = ("January","February","March","April","May","June",
           "July","August","September","October","November","December");
   ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
   $date = sprintf("%s $mday, 19$year, $hour:%02d",$month_names[$mon],$min);
}