Andy Wardley > Template-XML-2.17 > Template::Plugin::XML::DOM

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Module Version: 2.7   Source  

NAME ^

Template::Plugin::XML::DOM - Plugin interface to XML::DOM

SYNOPSIS ^

    # load plugin
    [% USE dom = XML.DOM %]

    # also provide XML::Parser options
    [% USE dom = XML.DOM(ProtocolEncoding = 'ISO-8859-1') %]

    # parse an XML file
    [% doc = dom.parse(filename) %]
    [% doc = dom.parse(file = filename) %]

    # parse XML text
    [% doc = dom.parse(xmltext) %]
    [% doc = dom.parse(text = xmltext) %]

    # call any XML::DOM methods on document/element nodes
    [% FOREACH node = doc.getElementsByTagName('report') %]
       * [% node.getAttribute('title') %]   # or [% node.title %]
    [% END %]

    # define VIEW to present node(s)
    [% VIEW report notfound='xmlstring' %]
       # handler block for a <report>...</report> element
       [% BLOCK report %]
          [% item.content(view) %]
       [% END %]

       # handler block for a <section title="...">...</section> element
       [% BLOCK section %]
       <h1>[% item.title %]</h1>
       [% item.content(view) %]
       [% END %]

       # default template block converts item to string
       [% BLOCK xmlstring; item.toString; END %]
       
       # block to generate simple text
       [% BLOCK text; item; END %]
    [% END %]

    # now present node (and children) via view
    [% report.print(node) %]

    # or print node content via view
    [% node.content(report) %]

    # following methods are soon to be deprecated in favour of views
    [% node.toTemplate %]
    [% node.childrenToTemplate %]
    [% node.allChildrenToTemplate %]

DESCRIPTION ^

This is a Template Toolkit plugin interfacing to the XML::DOM module. The plugin loads the XML::DOM module and creates an XML::DOM::Parser object which is stored internally. The parse() method can then be called on the plugin to parse an XML stream into a DOM document.

    [% USE dom = XML.DOM %]
    [% doc = dom.parse('/tmp/myxmlfile') %]

The XML::DOM plugin object (i.e. 'dom' in these examples) acts as a sentinel for the documents it creates ('doc' and any others). When the plugin object goes out of scope at the end of the current template, it will automatically call dispose() on any documents that it has created. Note that if you dispose of the the plugin object before the end of the block (i.e. by assigning a new value to the 'dom' variable) then the documents will also be disposed at that point and should not be used thereafter.

    [% USE dom = XML.DOM %]
    [% doc = dom.parse('/tmp/myfile') %]
    [% dom = 'new value' %]     # releases XML.DOM plugin and calls
                                # dispose() on 'doc', so don't use it!

The plugin constructor will also accept configuration options destined for the XML::Parser object:

    [% USE dom = XML.DOM(ProtocolEncoding = 'ISO-8859-1') %]

METHODS ^

parse()

The parse() method accepts a positional parameter which contains a filename or XML string. It is assumed to be a filename unless it contains a < character.

    [% xmlfile = '/tmp/foo.xml' %]
    [% doc = dom.parse(xmlfile) %]

    [% xmltext = BLOCK %]
    <xml>
      <blah><etc/></blah>
      ...
    </xml>
    [% END %]
    [% doc = dom.parse(xmltext) %]

The named parameters 'file' (or 'filename') and 'text' (or 'xml') can also be used:

    [% doc = dom.parse(file = xmlfile) %]
    [% doc = dom.parse(text = xmltext) %]

The parse() method returns an instance of the XML::DOM::Document object representing the parsed document in DOM form. You can then call any XML::DOM methods on the document node and other nodes that its methods may return. See XML::DOM for full details.

    [% FOREACH node = doc.getElementsByTagName('CODEBASE') %]
       * [% node.getAttribute('href') %]
    [% END %]

This plugin also provides an AUTOLOAD method for XML::DOM::Node which calls getAttribute() for any undefined methods. Thus, you can use the short form of

    [% node.attrib %]

in place of

    [% node.getAttribute('attrib') %]

PRESENTING DOM NODES USING VIEWS ^

You can define a VIEW to present all or part of a DOM tree by automatically mapping elements onto templates. Consider a source document like the following:

    <report>
      <section title="Introduction">
        <p>
        Blah blah.
        <ul>
          <li>Item 1</li>
          <li>item 2</li>
        </ul>
        </p>
      </section>
      <section title="The Gory Details">
        ...
      </section>
    </report>

We can load it up via the XML::DOM plugin and fetch the node for the <report> element.

    [% USE dom = XML.DOM;
       doc = dom.parse(file = filename);
       report = doc.getElementsByTagName('report')
    %]

We can then define a VIEW as follows to present this document fragment in a particular way. The Template::Manual::Views documentation contains further details on the VIEW directive and various configuration options it supports.

    [% VIEW report_view notfound='xmlstring' %]
       # handler block for a <report>...</report> element
       [% BLOCK report %]
          [% item.content(view) %]
       [% END %]

       # handler block for a <section title="...">...</section> element
       [% BLOCK section %]
       <h1>[% item.title %]</h1>
       [% item.content(view) %]
       [% END %]

       # default template block converts item to string representation
       [% BLOCK xmlstring; item.toString; END %]
       
       # block to generate simple text
       [% BLOCK text; item; END %]
    [% END %]

Each BLOCK defined within the VIEW represents a presentation style for a particular element or elements. The current node is available via the 'item' variable. Elements that contain other content can generate it according to the current view by calling [% item.content(view) %]. Elements that don't have a specific template defined are mapped to the 'xmlstring' template via the 'notfound' parameter specified in the VIEW header. This replicates the node as an XML string, effectively allowing general XML/XHTML markup to be passed through unmodified.

To present the report node via the view, we simply call:

    [% report_view.print(report) %]

The output from the above example would look something like this:

    <h1>Introduction</h1>
    <p>
    Blah blah.
    <ul>
      <li>Item 1</li>
      <li>item 2</li>
    </ul>
    </p>
  
    <h1>The Gory Details</h1>
    ...

To print just the content of the report node (i.e. don't process the 'report' template for the report node), you can call:

    [% report.content(report_view) %]

AUTHORS ^

This plugin module was written by Andy Wardley and Simon Matthews.

The XML::DOM module is by Enno Derksen and Clark Cooper. It extends the the XML::Parser module, also by Clark Cooper which itself is built on James Clark's expat library.

COPYRIGHT ^

Copyright (C) 2000-2006 Andy Wardley, Simon Matthews.

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

SEE ALSO ^

Template::Plugin, XML::DOM, XML::Parser

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