HTML::HTML5::Writer(3) output a DOM as HTML5

SYNOPSIS


use HTML::HTML5::Writer;

my $writer = HTML::HTML5::Writer->new;
print $writer->document($dom);

DESCRIPTION

This module outputs XML::LibXML::Node objects as HTML5 strings. It works well on DOM trees that represent valid HTML/XHTML documents; less well on other DOM trees.

Constructor

"$writer = HTML::HTML5::Writer->new(%opts)"
Create a new writer object. Options include:
  • markup

    Choose which serialisation of HTML5 to use: 'html' or 'xhtml'.

  • polyglot

    Set to true in order to attempt to produce output which works as both XML and HTML. Set to false to produce content that might not.

    If you don't explicitly set it, then it defaults to false for HTML, and true for XHTML.

  • doctype

    Set this to a string to choose which <!DOCTYPE> tag to output. Note, this purely sets the <!DOCTYPE> tag and does not change how the rest of the document is output. This really is just a plain string literal... 

     # Yes, this works...
 my $w = HTML::HTML5::Writer->new(doctype => '<!doctype html>');

    The following constants are provided for convenience: DOCTYPE_HTML2, DOCTYPE_HTML32, DOCTYPE_HTML4 (latest stable strict HTML 4.x), DOCTYPE_HTML4_RDFA (latest stable HTML 4.x+RDFa), DOCTYPE_HTML40 (strict), DOCTYPE_HTML40_FRAMESET, DOCTYPE_HTML40_LOOSE, DOCTYPE_HTML40_STRICT, DOCTYPE_HTML401 (strict), DOCTYPE_HTML401_FRAMESET, DOCTYPE_HTML401_LOOSE, DOCTYPE_HTML401_RDFA10, DOCTYPE_HTML401_RDFA11, DOCTYPE_HTML401_STRICT, DOCTYPE_HTML5, DOCTYPE_LEGACY (about:legacy-compat), DOCTYPE_NIL (empty string), DOCTYPE_XHTML1 (strict), DOCTYPE_XHTML1_FRAMESET, DOCTYPE_XHTML1_LOOSE, DOCTYPE_XHTML1_STRICT, DOCTYPE_XHTML11, DOCTYPE_XHTML_BASIC, DOCTYPE_XHTML_BASIC_10, DOCTYPE_XHTML_BASIC_11, DOCTYPE_XHTML_MATHML_SVG, DOCTYPE_XHTML_RDFA (latest stable strict XHTML+RDFa), DOCTYPE_XHTML_RDFA10, DOCTYPE_XHTML_RDFA11.

    Defaults to DOCTYPE_HTML5 for HTML and DOCTYPE_LEGACY for XHTML.

  • charset

    This module always returns strings in Perl's internal utf8 encoding, but you can set the 'charset' option to 'ascii' to create output that would be suitable for re-encoding to ASCII (e.g. it will entity-encode characters which do not exist in ASCII).

  • quote_attributes

    Set this to a true to force attributes to be quoted. If not explicitly set, the writer will automatically detect when attributes need quoting.

  • voids

    Set this to true to force void elements to always be terminated with '/>'. If not explicitly set, they'll only be terminated that way in polyglot or XHTML documents.

  • start_tags and end_tags

    Except in polyglot and XHTML documents, some elements allow their start and/or end tags to be omitted in certain circumstances. By setting these to true, you can prevent them from being omitted.

  • refs

    Special characters that can't be encoded as named entities need to be encoded as numeric character references instead. These can be expressed in decimal or hexadecimal. Setting this option to 'dec' or 'hex' allows you to choose. The default is 'hex'.

Public Methods

"$writer->document($node)"
Outputs (i.e. returns a string that is) an XML::LibXML::Document as HTML.
"$writer->element($node)"
Outputs an XML::LibXML::Element as HTML.
"$writer->attribute($node)"
Outputs an XML::LibXML::Attr as HTML.
"$writer->text($node)"
Outputs an XML::LibXML::Text as HTML.
"$writer->cdata($node)"
Outputs an XML::LibXML::CDATASection as HTML.
"$writer->comment($node)"
Outputs an XML::LibXML::Comment as HTML.
"$writer->pi($node)"
Outputs an XML::LibXML::PI as HTML.
"$writer->doctype"
Outputs the writer's DOCTYPE.
"$writer->encode_entities($string, characters=>$more)"
Takes a string and returns the same string with some special characters replaced. These special characters do not include any of '&', '<', '>' or '"', but you can provide a string of additional characters to treat as special: 

 $encoded = $writer->encode_entities($raw, characters=>'&<>"');
"$writer->encode_entity($char)"
Returns $char entity-encoded. Encoding is done regardless of whether $char is ``special'' or not.
"$writer->is_xhtml"
Boolean indicating if $writer is configured to output XHTML.
"$writer->is_polyglot"
Boolean indicating if $writer is configured to output polyglot HTML.
"$writer->should_force_start_tags"
"$writer->should_force_end_tags"
Booleans indicating whether optional start and end tags should be forced.
"$writer->should_quote_attributes"
Boolean indicating whether attributes need to be quoted.
"$writer->should_slash_voids"
Boolean indicating whether void elements should be closed in the XHTML style.

BUGS AND LIMITATIONS

Certain DOM constructs cannot be output in non-XML HTML. e.g. 

 my $xhtml = <<XHTML;
 <html xmlns="http://www.w3.org/1999/xhtml">
  <head><title>Test</title></head>
  <body><hr>This text is within the HR element</hr></body>
 </html>
 XHTML
 my $dom    = XML::LibXML->new->parse_string($xhtml);
 my $writer = HTML::HTML5::Writer->new(markup=>'html');
 print $writer->document($dom);

In HTML, there's no way to serialise that properly in HTML. Right now this module just outputs that HR element with text contained within it, a la XHTML. In future versions, it may emit a warning or throw an error.

In these cases, the HTML::HTML5::{Parser,Writer} combination is not round-trippable.

Outputting elements and attributes in foreign (non-XHTML) namespaces is implemented pretty naively and not thoroughly tested. I'd be interested in any feedback people have, especially on round-trippability of SVG, MathML and RDFa content in HTML.

Please report any bugs to <http://rt.cpan.org/>.

AUTHOR

Toby Inkster <[email protected]>.

COPYRIGHT AND LICENSE

Copyright (C) 2010-2012 by Toby Inkster.

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

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