#!/usr/local/bin/perl

#############################################################################################
# This script logs visitors to web pages. It can be used as either a SSI, or                #
# can be called from a link. To use as a SSI, the $SSI variable must be set to 1.           #
# Conversly, to have it be called from links, have $SSI set to 0.                           #
# To call this script from a link it should have this syntax:                               #
# <a href="/pathToScript/logger.pl?dest=http://yourDomain.com/wherever">Click Here</a>      #
#                                                                                           #
# After the logging is done, it will redirect to the page you have after the ?dest=         #
# Log format can be changed, but by default it is like:                                     #
#                                                                                           #
# Date - IP - Host - Browser - Where they are going - Where they came from                  #
#############################################################################################
# This script may be modified at will. If you do anything cool with it, please let me know. #
# Do not sell this script without my permission and always leave the comments.              #
# Kevin Meltzer 3/12/97 kmeltz@cris.com | www.ctcom.com/~kmeltz                             #
#############################################################################################

# Set variables

$SSI = 0;       # 0 - Used from link
                # 1 - Used as Server Side Include
                # 2 - Used from <img> tag

$logfile = "redirlemon.log";    # Your log file, must be chmod 666
$ip = $ENV{'REMOTE_ADDR'};
$browser = $ENV{'HTTP_USER_AGENT'};
$referer = $ENV{'HTTP_REFERER'};
$here = $ENV{'DOCUMENT_URI'};
@digits = split (/\./, $ip);
$address = pack ("C4", @digits);
$host = gethostbyaddr ($address, 2);

# From Link
if ($SSI eq 0) {
&parse_query;
&clean;
$dest = $query{'dest'};
&write_file;
&redirect;
}

# From SSI
if ($SSI eq 1) {
&write_file;
}

# From <img> tag
if ($SSI eq 2) {
&parse_query;
&clean;
$this = $query{'dest'};
&write_file;
&show_img;
}

################################################
# Parse the query then clean it up for our uses
################################################

sub parse_query {
    @query_strings = split("&", $ENV{"QUERY_STRING"});
    foreach $q (@query_strings) {
        ($attr, $val) = split("=", $q);
        $query{$attr} = $query{$attr}." ".$val;
    }
}



sub clean {
    if ($query{'dest'} =~ /\/$/) {
        chop($query{'dest'});
    }
    #$query{'dest'} =~ s/http\:\/\///g;
    #$query{'dest'} =~ s/\//_\|_/g;
}

################################################
# Go!
################################################

sub redirect {
print "Location: $dest\n\n";
}

################################################
# Write information to the log
################################################

sub write_file {
if (! (-f "$logfile")) {
open (LOG, ">$logfile");
close LOG;
}

&date;
open (LOG,">>$logfile") || die "Can't write to log file";
if ($SSI eq 0) {
print LOG "$date - $ip - $host - $browser - $dest - $referer\n";
  }
elsif ($SSI eq 1) {
print LOG "$date - $ip - $host - $browser - $here - $referer\n";
}
else {
print LOG "$date - $ip - $host - $browser - $this - $referer\n ";
}
close LOG;
} # end sub

#################################################
# Get date and show it in mm/dd/yy format
#################################################

sub date {
   ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst) = localtime(time);
   @months = ("1","2","3","4","5","6","7","8","9","10","11","12");
   $date = "@months[$mon]/$mday/$year - $hour:$min:$sec";
}

#################################################
# Subroutine to return a 1-pixel transparent gif
#################################################

sub show_img {
$! = 1;
$| = 1;
print "Content-type: image/gif\n\nGIF89a\1\0\1\0\200\0\0\0\0\0\0\0\0!\371\4\1\0\0\0\0,\0\0\0\0\1\0\1\0\0\2\2D\1\0\n";
}


# End