#!/usr/bin/perl

###########################################
#  Whos On Now? v1.0 by Allen C. Huffman  #
# Copyright (C) 2001 by Sub-Etha Software #
#                FREEWARE!                #
#            subetha@pobox.com            #
#      http://disneyfans.com/subetha      #
###########################################
#
# You may do whatever you want with this code, provided you put a comment in that
# says "Baseed on" (or similar) and my original copyright notice above.
#
# Revision History:
#
# 2001/08/05 1.0 Initial (working) version.
#

#
# Specify how many SECONDS has to pass before a visitor is considered no longer
# on the site.  For instance, setting the value to 60 will show the count of
# how many times the page has been loaded within the past 60 seconds.
#
$timespan = 300;

#
# If you want the display to show the timespan ("in the past X seconds/minutes")
# then set this value to 1.  If it is set to 0, the output will read "currently
# on the site".
#
$showtimespan = 1;

#
# Define the path and file name for the data file.
#
$whosonnow_file = "sewhosonnow.dat";

####################################################################################
#
# Begin processing... Nothing below this line needs to be modified.
#
print "Content-type: text/html\n\n";

# get the IP address of the current page visitor.
$currentip = $ENV{REMOTE_ADDR};

# if no IP, use a bogus one
if ( !$currentip ) {
	$currentip = "127.0.0.1";
}

# open (or create) the visitor log file.
unless ( open(FILE, "+<$whosonnow_file") ) {
	open( FILE,"+>$whosonnow_file") || die ("Unable to create file.\n" );
}

# read the entire contents into an array.
@file = <FILE>;

# get the current system time (in seconds)
$currenttime = time;

# back up to start of file and erase it
seek(FILE,0,0);
truncate(FILE,0);

# scan through previous visitors until we find one that has
# visited within the specified amount of time
$visitors = 1;

# check each entry of the log file.
foreach $line (@file)
{
	# split the line into ipaddress and timestamp.
	( $ipaddr, $timestamp ) = split(" ",$line);

	# is this an old entry or a repeate visitor within the timespan?
	unless ( ($timestamp < $currenttime-$timespan) || ($ipaddr eq $currentip) )
	{
		# this is within the specified period, so count it...
		$visitors++;
		# then save it back to the file.
		print FILE "$ipaddr $timestamp\n";
	}
}

# write the current IP and timestamp to the end of the file.
print FILE "$currentip $currenttime\n";

# display how many visitors are on the site.
print "$visitors visitor";
if ( $visitors!=1 ) {
	print "s";
}

# and, if selected, the timespan.
if ( $showtimespan ) {
	print " within the past ";
	if ( $timespan<60 ) {
		print "$timespan seconds.";
	} else {
		$minutes = $timespan/60;
		print "$minutes minute";
		if ( $minutes!=1 ) {
			print "s";
		}
		print ".";
	}
} else {
	print " currently on the site.";
}

# just to make output easier to read when testing offline.
print "\n";

close(FILE);

exit(0);