NAME
    HTML::RewriteAttributes - concise attribute rewriting

SYNOPSIS
    Locate a tag in a provided block of HTML and delete, add, or rewrite the
    attributes associated with that tag. The updated HTML is returned.

    Delete an attribute by returning undef.

        $html = HTML::RewriteAttributes->rewrite($html, sub {
            my ($tag, $attr, $value) = @_;

            # delete any attribute that mentions..
            return if $value =~ /COBOL/i;

            $value =~ s/\brocks\b/rules/g;
            return $value;
        });

    Add an attribute by appending it to the $attr_list arrayref and adding
    the value to the $attrs hashref. For example, you could add
    "loading="lazy"" to all "img" tags.

        $html = HTML::RewriteAttributes->rewrite($html, sub {
            my ( $tag, $attr, $value, $attrs, $attr_list ) = @_;
            return $value unless $tag eq 'img' && !$attrs->{loading};
            $attrs->{loading} = 'lazy';
            push @$attr_list, 'loading';
            return $value;
        });

    Modify an existing attribute by returning the new value. The example
    below would be a "src" attribute for an "img" in an email.

        $html = HTML::RewriteAttributes::Resources->rewrite($html, sub {
            my $uri = shift;
            my $content = render_template($uri);
            my $cid = generate_cid_from($content);
            $mime->attach($cid => content);
            return "cid:$cid";
        });

    Passing a URL, HTML::RewriteAttributes::Links can update resources like
    "href"s or "img"s to include the base URL, changing "<img
    src="/bar.gif">" to "<img src="https://search.cpan.org/bar.gif">". See
    also HTML::ResolveLink.

        $html = HTML::RewriteAttributes::Links->rewrite($html, "https://search.cpan.org");

        # Passing a subroutine reference, L<HTML::RewriteAttributes::Links> can
        # extract all links, similar to L<HTML::LinkExtor>.

        HTML::RewriteAttributes::Links->rewrite($html, sub {
            my ($tag, $attr, $value) = @_;
            push @links, $value;
            $value;
        });

DESCRIPTION
    "HTML::RewriteAttributes" is designed for simple yet powerful HTML
    attribute rewriting.

    You simply specify a callback to run for each attribute and we do the
    rest for you.

    This module is designed to be subclassable to make handling special
    cases easier. See the source for methods you can override.

    See the SYNOPSIS above and included tests in the "t" directory for more
    examples.

METHODS
  "new"
    You don't need to call "new" explicitly - it's done in "rewrite". It
    takes no arguments.

  "rewrite" HTML, callback -> HTML
    This is the main interface of the module. You pass in some HTML and a
    callback, the callback is invoked potentially many times, and you get
    back some similar HTML.

    As "rewrite" parses the HTML block, it calls the provided callback,
    passing as arguments the current tag name, the attribute name, and the
    attribute value (though subclasses may override this --
    HTML::RewriteAttributes::Resources does). The callback can then use the
    arguments to determine if you want to change the current tag or
    attribute, or skip it by returning the current value unchanged. If you
    find the tag and attribute you want to change, return "undef" to remove
    the attribute, or any other value to set the value of the attribute.

    The callback also is passed a hashref $attrs which has keys for
    attributes and values with the current values. Finally $attr_list is
    passed as an arrayref contain all attributes for the current tag. To add
    a new attribute, add the attribute name to the $attr_list arrayref, and
    add the new value to $attrs.

SEE ALSO
    HTML::Parser, HTML::ResolveLink, Email::MIME::CreateHTML,
    HTML::LinkExtor

THANKS
    Some code was inspired by, and tests borrowed from, Miyagawa's
    HTML::ResolveLink.

AUTHOR
    Best Practical Solutions, LLC <modules@bestpractical.com>

LICENSE
    Copyright 2008-2024 Best Practical Solutions, LLC.
    HTML::RewriteAttributes is distributed under the same terms as Perl
    itself.