NAME
HTML::Scrubber - Perl extension for scrubbing/sanitizing html
VERSION
version 0.09
SYNOPSIS
use HTML::Scrubber;
my $scrubber = HTML::Scrubber->new( allow => [ qw[ p b i u hr br ] ] );
print $scrubber->scrub('<p><b>bold</b> <em>missing</em></p>');
# output is: <p><b>bold</b> </p>
# more complex input
my $html = q[
<style type="text/css"> BAD { background: #666; color: #666;} </style>
<script language="javascript"> alert("Hello, I am EVIL!"); </script>
<HR>
a => <a href=1>link </a>
br => <br>
b => <B> bold </B>
u => <U> UNDERLINE </U>
];
print $scrubber->scrub($html);
$scrubber->deny( qw[ p b i u hr br ] );
print $scrubber->scrub($html);
DESCRIPTION
If you wanna "scrub" or "sanitize" html input in a reliable and flexible fashion, then this module is for you.
I wasn't satisfied with HTML::Sanitizer because it is based on HTML::TreeBuilder, so I thought I'd write something similar that works directly with HTML::Parser.
METHODS
First a note on documentation: just study the EXAMPLE below. It's all the documentation you could need
Also, be sure to read all the comments as well as How does it work?.
If you're new to perl, good luck to you.
comment
warn "comments are ", $p->comment ? 'allowed' : 'not allowed';
$p->comment(0); # off by default
process
warn "process instructions are ", $p->process ? 'allowed' : 'not allowed';
$p->process(0); # off by default
script
warn "script tags (and everything in between) are supressed"
if $p->script; # off by default
$p->script( 0 || 1 );
** Please note that this is implemented using HTML::Parser's ignore_elements function, so if "script" is set to true, all script tags encountered will be validated like all other tags.
style
warn "style tags (and everything in between) are supressed"
if $p->style; # off by default
$p->style( 0 || 1 );
** Please note that this is implemented using HTML::Parser's ignore_elements function, so if "style" is set to true, all style tags encountered will be validated like all other tags.
allow
$p->allow(qw[ t a g s ]);
deny
$p->deny(qw[ t a g s ]);
rules
$p->rules(
img => {
src => qr{^(?!http://)}i, # only relative image links allowed
alt => 1, # alt attribute allowed
'*' => 0, # deny all other attributes
},
b => 1,
...
);
default
print "default is ", $p->default();
$p->default(1); # allow tags by default
$p->default(
undef, # don't change
{ # default attribute rules
'*' => 1, # allow attributes by default
}
);
scrub_file
$html = $scrubber->scrub_file('foo.html'); ## returns giant string
die "Eeek $!" unless defined $html; ## opening foo.html may have failed
$scrubber->scrub_file('foo.html', 'new.html') or die "Eeek $!";
$scrubber->scrub_file('foo.html', *STDOUT)
or die "Eeek $!"
if fileno STDOUT;
scrub
print $scrubber->scrub($html); ## returns giant string
$scrubber->scrub($html, 'new.html') or die "Eeek $!";
$scrubber->scrub($html', *STDOUT)
or die "Eeek $!"
if fileno STDOUT;
default handler, used by both _scrub and scrubfh Moved all the common code (ie all of it) into a single routine for ease of maintenance
default handler, does the scrubbing if we're scrubbing out to a file. Now calls scrubstr and pushes that out to a file.
default handler, does the scrubbing if we're returning a giant string. Now calls scrubstr and appends that to the output string.
How does it work?
When a tag is encountered, HTML::Scrubber allows/denies the tag using the explicit rule if one exists.
If no explicit rule exists, Scrubber applies the default rule.
If an explicit rule exists, but it's a simple rule(1), the default attribute rule is applied.
EXAMPLE
#!/usr/bin/perl -w
use HTML::Scrubber;
use strict;
my @allow = qw[ br hr b a ];
my @rules = (
script => 0,
img => {
src => qr{^(?!http://)}i, # only relative image links allowed
alt => 1, # alt attribute allowed
'*' => 0, # deny all other attributes
},
);
my @default = (
0 => # default rule, deny all tags
{
'*' => 1, # default rule, allow all attributes
'href' => qr{^(?!(?:java)?script)}i,
'src' => qr{^(?!(?:java)?script)}i,
# If your perl doesn't have qr
# just use a string with length greater than 1
'cite' => '(?i-xsm:^(?!(?:java)?script))',
'language' => 0,
'name' => 1, # could be sneaky, but hey ;)
'onblur' => 0,
'onchange' => 0,
'onclick' => 0,
'ondblclick' => 0,
'onerror' => 0,
'onfocus' => 0,
'onkeydown' => 0,
'onkeypress' => 0,
'onkeyup' => 0,
'onload' => 0,
'onmousedown' => 0,
'onmousemove' => 0,
'onmouseout' => 0,
'onmouseover' => 0,
'onmouseup' => 0,
'onreset' => 0,
'onselect' => 0,
'onsubmit' => 0,
'onunload' => 0,
'src' => 0,
'type' => 0,
}
);
my $scrubber = HTML::Scrubber->new();
$scrubber->allow( @allow );
$scrubber->rules( @rules ); # key/value pairs
$scrubber->default( @default );
$scrubber->comment(1); # 1 allow, 0 deny
## preferred way to create the same object
$scrubber = HTML::Scrubber->new(
allow => \@allow,
rules => \@rules,
default => \@default,
comment => 1,
process => 0,
);
require Data::Dumper,die Data::Dumper::Dumper($scrubber) if @ARGV;
my $it = q[
<?php echo(" EVIL EVIL EVIL "); ?> <!-- asdf -->
<hr>
<I FAKE="attribute" > IN ITALICS WITH FAKE="attribute" </I><br>
<B> IN BOLD </B><br>
<A NAME="evil">
<A HREF="javascript:alert('die die die');">HREF=JAVA <!></A>
<br>
<A HREF="image/bigone.jpg" ONMOUSEOVER="alert('die die die');">
<IMG SRC="image/smallone.jpg" ALT="ONMOUSEOVER JAVASCRIPT">
</A>
</A> <br>
];
print "original text",$/, $it, $/;
print
"scrubbed text (default ",
$scrubber->default(), # no arguments returns the current value
" comment ",
$scrubber->comment(),
" process ",
$scrubber->process(),
" )",
$/,
$scrubber->scrub($it),
$/;
$scrubber->default(1); # allow all tags by default
$scrubber->comment(0); # deny comments
print
"#scrubbed text (default ",
$scrubber->default(),
" comment ",
$scrubber->comment(),
" process ",
$scrubber->process(),
" )",
$/,
$scrubber->scrub($it),
$/;
$scrubber->process(1); # allow process instructions (dangerous)
$default[0] = 1; # allow all tags by default
$default[1]->{'*'} = 0; # deny all attributes by default
$scrubber->default(@default); # set the default again
print
"#scrubbed text (default ",
$scrubber->default(),
" comment ",
$scrubber->comment(),
" process ",
$scrubber->process(),
" )",
$/,
$scrubber->scrub($it),
$/;
FUN
If you have Test::Inline (and you've installed HTML::Scrubber), try
pod2test Scrubber.pm >scrubber.t
perl scrubber.t
SEE ALSO
HTML::Parser, Test::Inline, HTML::Sanitizer.
INSTALLATION
See perlmodinstall for information and options on installing Perl modules.
BUGS AND LIMITATIONS
No bugs have been reported.
Please report any bugs or feature requests through the web interface at <http://rt.cpan.org/Public/Dist/Display.html?Name=HTML-Scrubber>.
AVAILABILITY
The project homepage is <http://search.cpan.org/dist/HTML-Scrubber>.
The latest version of this module is available from the Comprehensive Perl Archive Network (CPAN). Visit <http://www.perl.com/CPAN/> to find a CPAN site near you, or see <http://search.cpan.org/dist/HTML-Scrubber/>.
The development version lives at
<http://github.com/nigelm/html-scrubber> and may be cloned from
<git://github.com/nigelm/html-scrubber.git>. Instead of sending patches,
please fork this project using the standard git and github
infrastructure.
AUTHORS
COPYRIGHT AND LICENSE
This software is copyright (c) 2011 by Nigel Metheringham, 2003-2004 D. H..
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.