Provided by: libtemplate-plugin-xml-perl_2.17-3_all 
NAME
Template::Plugin::XML::LibXML - XML::LibXML Template Toolkit Plugin
SYNOPSIS
[% USE docroot = XML.LibXML("helloworld.xml") %]
The message is: [% docroot.find("/greeting/text") %]
DESCRIPTION
This module provides a plugin for the XML::LibXML module. It can be utilised the same as
any other Template Toolkit plugin, by using a USE statement from within a Template. The
use statment will return a reference to root node of the parsed document
Specifying a Data Source
The plugin is capable of using either a string, a filename or a filehandle as a source for
either XML data, or HTML data which will be converted to XHTML internally.
The USE statement can take one or more arguments to specify what XML should be processed.
If only one argument is passed then the plugin will attempt to guess how what it has been
passed should be interpreted.
When it is forced to guess what type of data it is used the routine will first look for an
open filehandle, which if it finds it will assume it's a filehandle to a file containing
XML. Failing this (in decreasing order) it will look for the chars "<?xml" at the start
of what it was passed (and assume it's an XML string,) look for a "<html>" tag (and assume
it's HTML string,) look for a "<" (and assume it's XML string without a header,) or assume
what it's been passed is the filename to a file containing XML.
In the interests of being explicit, you may specify the type of data you are loading using
the same names as in the XML::LibXML documentation:
# value contains the xml string
[% USE docroot = XML.LibXML(string => value) %]
# value contains the filename of the xml
[% USE docroot = XML.LibXML(file => value) %]
# value contains an open filehandle to some xml
[% USE docroot = XML.LibXML(fh => value) %]
# value contains the html string
[% USE docroot = XML.LibXML(html_string => value) %]
# value contains the filename of the html
[% USE docroot = XML.LibXML(html_file => value) %]
# value contains an open filehandle to some html
[% USE docroot = XML.LibXML(html_fh => value) %]
Or, if you want you can use similar names to that the XML.XPath plugin uses:
# value contains the xml string
[% USE docroot = XML.LibXML(xml => value) %] or
[% USE docroot = XML.LibXML(text => value) %]
# value contains the filename of the xml
[% USE docroot = XML.LibXML(filename => value) %]
# value contains the html string
[% USE docroot = XML.LibXML(html => value) %] or
[% USE docroot = XML.LibXML(html_text => value) %]
# value contains the filename of the html
[% USE docroot = XML.LibXML(html_file => value) %]
[% USE docroot = XML.LibXML(html_filename => value) %]
You can provide extra arguments which will be used to set parser options. See XML::LibXML
for details on these. I will repeat the following warning however: "LibXML options are
global (unfortunately this is a limitation of the underlying implementation, not this
interface)...Note that even two forked processes will share some of the same options, so
be careful out there!"
# turn off expanding entities
[% USE docroot = XML.LibXML("file.xml",
expand_entities => 0);
Obtaining Parts of an XML Document
XML::LibXML provides two simple mechanisms for obtaining sections of the XML document,
both of which can be used from within the Template Toolkit
The first of these is to use a XPath statement. Simple values can be found with the
"findvalue" routine:
# get the title attribute of the first page node
# (note xpath starts counting from one not zero)
[% docroot.findvalue("/website/section/page[1]/@title"); %]
# get the text contained within a node
[% htmldoc.findvalue("/html/body/h1[1]/text()") %]
Nodes of the xml document can be found with the "findnodes"
# get all the pages ('pages' is a list of nodes)
[% pages = docroot.findnodes("/website/section/page") %]
# get the first page (as TT folds single elements arrays
# to scalars, 'page1' is the one node that matched)
[% page1 = docroot.findnodes("/website/section/page[1]") %]
Then further xpath commands can then be applied to those nodes in turn:
# get the title attribute of the first page
[% page1.findvalue("@title") %]
An alternative approach is to use individual method calls to move around the tree. So the
above could be written:
# get the text of the h1 node
[% htmlroot.documentElement
.getElementsByLocalName("body").first
.getElementsByLocalName("h1").first
.textContent %]
# get the title of the first page
[% docroot.documentElement
.getElementsByLocalName("section").first
.getElementsByLocalName("page").first
.getAttribute("title") %]
You should use the technique that makes the most since in the particular situation. These
approaches can even be mixed:
# get the first page title
[% page1 = htmlroot.findnodes("/website/section/page[1]");
page1.getAttribute("title") %]
Much more information can be found in XML::LibXML::Node.
Rendering XML
The simplest way to use this plugin is simply to extract each value you want to print by
hand
The title of the first page is '[%
docroot.findvalue("/website/section/page[1]/@title") %]'
or
The title of the first page is '[%
docroot.documentElement
.getElementsByLocalName("section").first
.getElementsByLocalName("page").first
.getAttribute("title") %]'
You might want to discard whitespace from text areas. XPath can remove all leading and
following whitespace, and condense all multiple spaces in the text to single spaces.
<p>[% htmlroot.findvalue("normalize-space(
/html/body/p[1]/text()
)" | html %]</p>
Note that, as above, when we're inserting the values extracted into a XML or HTML document
we have to be careful to re-encode the attributes we need to escape with something like
the html filter. A slightly more advanced technique is to extract a whole node and use
the toString method call on it to convert it to a string of XML. This is most useful when
you are extracting an existing chunk of XML en mass, as things like <b> and <i> tags will
be passed thought correctly and entities will be encoded suitably (for example '"' will be
turned into '"')
# get the second paragraph and insert it here as XML
[% htmlroot.findnodes("/html/body/p[2]").toString %]
The most powerful technique is to use a view (as defined by the VIEW keyword) to
recursively render out the XML. By loading this plugin "present" methods will be created
in the XML::LibXML::Node classes and subclasses. Calling "present" on a node with a VIEW
will cause it to be rendered by the view block matching the local name of that node (with
any non alphanumeric charecters turned to underscores. So a <author> tag will be rendered
by the 'author' block. Text nodes will call the 'text' block with the text of the node.
As the blocks can refer back to both the node it was called with and the view they can
choose to recursively render out it's children using the view again. To better facilitate
this technique the extra methods "starttag" (recreate a string of the starting tag,
including attributes,) "endtag" (recreate a string of the ending tag) and "content" (when
called with a view, will render by calling all the children of that node in turn with that
view) have been added.
This is probably best shown with a well commented example:
# create the view
[% VIEW myview notfound => 'passthru' %]
# default tag that will recreate the tag 'as is' meaning
# that unknown tags will 'passed though' by the view
[% BLOCK passthru; item.starttag;
item.content(view);
item.endtag;
END %]
# convert all sections to headed paragraphs
[% BLOCK section %]
<h2>[% item.getAttribute("title") %]</h2>
<p>[% item.content(view) %]</p>
[% END %]
# urls link to themselves
[% BLOCK url %]
<a href="[% item.content(view) %]">[% item.content(view) %]</a>
[% END %]
# email link to themselves with mailtos
[% BLOCK email %]
<a href="mailto:[% item.content(view) %]">[% item.content(view) %]</a>
[% END %]
# make pod links bold
[% BLOCK pod %]
<b>[% item.content(view) %]</b>
[% END %]
# render text, re-encoding the attributes as we go
[% BLOCK text; item | html; END %]
# render arrays out
[% BLOCK list; FOREACH i = item; view.print(i); END ; END %]
[% END %]
# use it to render the paragraphs
[% USE doc = XML.LibXML("mydoc.xml") %]
<html>
<head>
<title>[% doc.findvalue("/doc/page[1]/@title") %]</title>
</head>
<body>
[% sections = doc.findnodes("/doc/page[1]/section");
FOREACH section = sections %]
<!-- next section -->
[% section.present(myview);
END %]
</body>
</html>
BUGS
In order to detect if a scalar is an open filehandle (which is used if the USE isn't
explicit about it's data source) this plugin uses the "openhandle" routine from
Scalar::Util. If you do not have Scalar::Util installed, or the version of Scalar::Util
is sufficiently old that it does not support the "openhandle" routine then a much cruder
"defined(fileno $scalar)" check will be employed.
Bugs may be reported either via the CPAN RT at
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Template-Plugin-XML-LibXML or via the Template
Toolkit mailing list: http://www.template-toolkit.org/mailman/listinfo/templates or direct
to the author
AUTHOR
Written by Mark Fowler <mark@twoshortplanks.com>
Copyright Mark Fowler 2002-3, all rights reserved.
This program is free software; you can redistribute it and/or modify it under the same
terms as Perl itself.
This module wouldn't have been possible without the wonderful work that has been put into
the libxml library by the gnome team or the equally wonderful work put in by Matt Sergeant
and Christian Glahn in creating XML::LibXML.
SEE ALSO
Template, Template::Plugin, XML::LibXML, XML::LibXML::Node.
On a similar note, you may want to see Template::Plugin::XML::XPath.
The t/test directory in the Template-Plugin-XML-LibXML distribution contains all the
example XML files discussed in this documentation.