package Obfuscator;
##############################################################
# Obfuscator                           (c) 2002-2003         #
#      Dean Peters                                           #
#      http://www.healyourchurchwebsite.com/obfuscator/      #
#                                                            #
# use Obfuscator;                                            #
# print "Problems? Questions? ".                             #
#        OB_encode( "obfuscater\@healyourchurchwebsite.org", #
#                   "drop me a line.",                       #
#                   "Problem? Praise? Email Me", true);      #
#                                                            #
##############################################################
#   This package obfuscates email                            #
##############################################################

require Exporter;
@ISA = qw(Exporter);
@EXPORT = qw(OB_encode OB_validmail);

use vars qw($volumes $books $versions);

sub OB_encode {
	my($email, $prompt, $title, $usejs) = @_;

	# return if email doesn't validate
	return   if( $email !~ /[\w\-\[\]<>\+]+(\@|\-at\-)[\w\-\[\]<>]+(\.|\-dot\-)[\w\-]+/i);

	# mangle address -- character at a time --except \@
	$email  =~ s/(:)([^\s])/$1 $2/;
	$email  =~ s/([a-zA-Z0-9:\s_\-.])/&OB_randlet($1)/eg;

	my $at = &OB_randlet("\@");
	my ($ename, $edomain) = split(/\@/, $email);
	my $link = $ename.$at.$edomain;

 	# want address only? no problem.
	return $link	if !($prompt || $title);

	# put a space between mailto: and the address (drives spammers crazy)
	my($mailto) = &OB_ascape("mailto:").&OB_hexape(" ");


	# build hyperlink based on use javascript argument (or not)
	$link = $usejs ?
		"javascript:var e1='$edomain',e2='$mailto', e3='$ename';var e0=e2+e3+'$at'+e1;(window.location?window.location.replace(e0):document.write(e0));" :
		$mailto.$link;

  	# try to use a title, but when you can't ...
	$prompt = &OB_ascape($prompt);
	return qq~<a href="$link">$prompt</a>~	if !($title);

	# got title?
	$title  = &OB_ascape($title);
	return qq~<a href="$link" title="$title">$prompt</a>~;
}

# http://ironbark.bendigo.latrobe.edu.au/subjects/bitwen/lectures/w08.d/l15.d/slide3.html
sub OB_validmail {
	my($email) = @_;
	return ( $email =~ /^([\w\-._]+\@[\w\-.]+)$/ );
}

# 2 randoms, 1st for hex vs ascii, then again for ascii vs plain
sub OB_randlet {
 	my($l) = @_;
	my($r) = &OB_round(rand());
 	return sprintf("%%%02x",ord($l))	if $r;
	$r = &OB_round(rand());
 	return sprintf("&#%03d;",ord($l))	if $r;
	return $l;
}

# real numbers only
sub OB_round {
	my($n) = @_;
	return int($n + .5 * ($n <=> 0));
}

# ascii escape codes
sub OB_ascape {
	my($s) = @_;
	$s =~ s/([a-zA-Z0-9:\s\@_\-.])/uc sprintf("&#%03d;",ord($1))/eg;
	return $s;
}

# hex it up a bit
sub OB_hexape {
	my($s) = @_;
	$s =~ s/([a-zA-Z0-9:\s\@_\-.])/uc sprintf("%%%02x",ord($1))/eg;
	return $s;
}

1;
__END__


=head1 NAME

Obfuscator - mangles email addresses to fool dumb spambots

=head1 SYNOPSIS

use Obfuscator;
print OB_encode($email, $prompt, $title, $usejs)  if OB_validmail($email);

$email  - required string representing an email address, remember, in Perl
          it's my $email = "foo\@bar.com" ... note the slash
$prompt - optional string of the prompt you want between the <a>..</a> tags
$title  - optional string that is used for title argument of <a> tag
$usejs  - renders obfuscated hyperlink as a javascript link

=head1 DESCRIPTION

Obfuscator  randomly converts your entries into a combination of numeric and
hexadecimal encodings, as well as a salting of some non-converted characters
that will either hide your e-mail address from spambots and/or cause their
mailers to gag because they're not expecting all three encoding in radom.
This program also obfuscates the prompts to give spambots less key words to
search, find and filche.

=head1 IMPROVEMENTS
* n/a

=head1 BUGS
* n/a

=head1 AUTHOR
  Dean Peters   <http://www.healyourchurchwebsite.com/obfuscator/>

=head1 EXAMPLE

use Obfuscator;
my $email = "obfuscater\@healyourchurchwebsite.org";
print "Problems? Questions? ".
      OB_encode($email, "drop me a line.",
      "Problem? Praise? Email Me", true)
       if OB_validmail($email);


=head1 COPYRIGHT and LICENSE

Copyright (c) 2002-2003
Dean Peters   <http://www.healyourchurchwebsite.com/obfuscator/>
  
Permission is hereby granted, free of charge, to any person obtaining a
copy of this software and associated documentation files (the "Software"),
to deal in the Software without restriction, including without limitation
the rights to use, copy, modify, merge, publish, distribute, sublicense,
and/or sell copies of the Software, and to permit persons to whom the
Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

The Software is not included in any commercial application or publication
without the expressed written permission of Dean Peters.

The Software is provided "as is", without warranty of any kind, express or
implied, including but not limited to the warranties of merchantability,
fitness for a particular purpose and noninfringement. In no event shall
the authors or copyright holders be liable for any claim, damages or other
liability, whether in an action of contract, tort or otherwise, arising
from, out of or in connection with the Software or the use or other
dealings in the Software.

=cut