NAME

    HTML::Scrubber - Perl extension for scrubbing/sanitizing HTML

VERSION

    version 0.18

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 want to "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.

 new

        my $scrubber = HTML::Scrubber->new( allow => [ qw[ p b i u hr br ] ] );

    Build a new HTML::Scrubber. The arguments are the initial values for
    the following directives:-

      * default

      * allow

      * deny

      * rules

      * process

      * comment

 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
            },
            a => {
                href => sub { ... },      # check or adjust with a callback
            },
            b => 1,
            ...
        );

    Updates a set of attribute rules. Each rule can be 1/0, a regular
    expression or a callback. Values longer than 1 char are treated as
    regexps. The callback is called with the following arguments: the
    current object, tag name, attribute name, and attribute value; the
    callback should return an empty list to drop the attribute, undef to
    keep it without a value, or a new scalar value.

 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 _scrub_fh. Moved all the
    common code (basically 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 _scrub_str and pushes that out to a file.

    default handler, does the scrubbing if we're returning a giant string.
    Now calls _scrub_str 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), then 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{^(?:http|https|ftp)://}i,
                'src'  => qr{^(?:http|https|ftp)://}i,
    
                #   If your perl doesn't have qr
                #   just use a string with length greater than 1
                'cite'        => '(?i-xsm:^(?:http|https|ftp):)',
                '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 &lt;!&gt;</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.

    The HTML::Sanitizer module is no longer available on CPAN.

VERSION REQUIREMENTS

    As of version 0.14 I have added a perl minimum version requirement of
    5.8. This is basically due to failures on the smokers perl 5.6
    installations - which appears to be down to installation mechanisms and
    requirements.

    Since I don't want to spend the time supporting a version that is so
    old (and may not work for reasons on UTF support etc), I have added a
    use 5.008; to the main module.

    If this is problematic I am very willing to accept patches to fix this
    up, although I do not personally see a good reason to support a release
    that has been obsolete for 13 years.

CONTRIBUTING

    If you want to contribute to the development of this module, the code
    is on GitHub <http://github.com/nigelm/html-scrubber>. You'll need a
    perl environment with Dist::Zilla, and if you're just getting started,
    there's some documentation on using Vagrant and Perlbrew here
    <http://mrcaron.github.io/2015/03/06/Perl-CPAN-Pull-Request.html>.

    There is now a .perltidyrc and a .tidyallrc file within the repository
    for the standard perltidy settings used - I will apply these before new
    releases. Please do not let formatting prevent you from sending in
    patches etc - this can be sorted out as part of the release process.
    Info on tidyall can be found at
    https://metacpan.org/pod/distribution/Code-TidyAll/bin/tidyall.

AUTHORS

      * Ruslan Zakirov <Ruslan.Zakirov@gmail.com>

      * Nigel Metheringham <nigelm@cpan.org>

      * D. H. <podmaster@cpan.org>

COPYRIGHT AND LICENSE

    This software is copyright (c) 2018 by Ruslan Zakirov, 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.

SUPPORT

 Perldoc

    You can find documentation for this module with the perldoc command.

      perldoc HTML::Scrubber

 Websites

    The following websites have more information about this module, and may
    be of help to you. As always, in addition to those websites please use
    your favorite search engine to discover more resources.

      * MetaCPAN

      A modern, open-source CPAN search engine, useful to view POD in HTML
      format.

      https://metacpan.org/release/HTML-Scrubber

      * Search CPAN

      The default CPAN search engine, useful to view POD in HTML format.

      http://search.cpan.org/dist/HTML-Scrubber

      * RT: CPAN's Bug Tracker

      The RT ( Request Tracker ) website is the default bug/issue tracking
      system for CPAN.

      https://rt.cpan.org/Public/Dist/Display.html?Name=HTML-Scrubber

      * AnnoCPAN

      The AnnoCPAN is a website that allows community annotations of Perl
      module documentation.

      http://annocpan.org/dist/HTML-Scrubber

      * CPAN Ratings

      The CPAN Ratings is a website that allows community ratings and
      reviews of Perl modules.

      http://cpanratings.perl.org/d/HTML-Scrubber

      * CPANTS

      The CPANTS is a website that analyzes the Kwalitee ( code metrics )
      of a distribution.

      http://cpants.cpanauthors.org/dist/HTML-Scrubber

      * CPAN Testers

      The CPAN Testers is a network of smoke testers who run automated
      tests on uploaded CPAN distributions.

      http://www.cpantesters.org/distro/H/HTML-Scrubber

      * CPAN Testers Matrix

      The CPAN Testers Matrix is a website that provides a visual overview
      of the test results for a distribution on various Perls/platforms.

      http://matrix.cpantesters.org/?dist=HTML-Scrubber

      * CPAN Testers Dependencies

      The CPAN Testers Dependencies is a website that shows a chart of the
      test results of all dependencies for a distribution.

      http://deps.cpantesters.org/?module=HTML::Scrubber

 Bugs / Feature Requests

    Please report any bugs or feature requests by email to
    bug-html-scrubber at rt.cpan.org, or through the web interface at
    https://rt.cpan.org/Public/Bug/Report.html?Queue=HTML-Scrubber. You
    will be automatically notified of any progress on the request by the
    system.

 Source Code

    The code is open to the world, and available for you to hack on. Please
    feel free to browse it and play with it, or whatever. If you want to
    contribute patches, please send me a diff or prod me to pull from your
    repository :)

    https://github.com/nigelm/html-scrubber

      git clone https://github.com/nigelm/html-scrubber.git

CONTRIBUTORS

      * Andrei Vereha <avereha@gmail.com>

      * Lee Johnson <lee@givengain.ch>

      * Michael Caron <michael.r.caron@gmail.com>

      * Michael Caron <mrcaron@users.noreply.github.com>

      * Nigel Metheringham <nm9762github@muesli.org.uk>

      * Paul Cochrane <paul@liekut.de>

      * Ruslan Zakirov <ruz@bestpractical.com>

      * Sergey Romanov <complefor@rambler.ru>

      * vagrant <vagrant@precise64.(none)>