LibXML

Section: User Contributed Perl Documentation (3)
Updated: 2003-03-07
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NAME

XML::SimpleObject::LibXML - Perl extension allowing a simple(r) object representation of an XML::LibXML DOM object.

SYNOPSIS

  use XML::SimpleObject::LibXML;

  # Construct with the key/value pairs as argument; this will create its 
  # own XML::LibXML object.
  my $xmlobj = new XML::SimpleObject(XML => $XML);

  # ... or construct with the parsed tree as the only argument, having to 
  # create the XML::Parser object separately.
  my $parser = new XML::LibXML;
  my $dom    = $parser->parse_file($file); # or $parser->parse_string($xml);
  my $xmlobj = new XML::SimpleObject::LibXML ($dom);

  my $filesobj = $xmlobj->child("files")->child("file");

  $filesobj->name;
  $filesobj->value;
  $filesobj->attribute("type");
  
  %attributes    = $filesobj->attributes;
  @children      = $filesobj->children;
  @some_children = $filesobj->children("some");
  @children_names = $filesobj->children_names;

DESCRIPTION

This is a short and simple class allowing simple object access to a parsed XML::LibXML tree, with methods for fetching children and attributes in as clean a manner as possible. My apologies for further polluting the XML:: space; this is a small and quick module, with easy and compact usage. Some will rightfully question placing another interface over the DOM methods provided by XML::LibXML, but my experience is that people appreciate the total simplicity provided by this module, despite its limitations.

USAGE

$xmlobj = new XML::SimpleObject::LibXML($parser->parse_string($XML)): $parser is an XML::LibXML object.
After creating $xmlobj, this object can now be used to browse the XML tree with the following methods.
$xmlobj->child('NAME'): This will return a new XML::SimpleObject::LibXML object using the child element NAME.
$xmlobj->children('NAME'): Called with an argument NAME, children() will return an array of XML::SimpleObject::LibXML objects of element NAME. Thus, if $xmlobj represents the top-level XML element, 'children' will return an array of all elements directly below the top-level that have the element name NAME.
$xmlobj->children: Called without arguments, 'children()' will return an array of XML::SimpleObjects::LibXML objects for all children elements of $xmlobj. Unlike XML::SimpleObject, XML::SimpleObject::LibXML retains the order of these children.
$xmlobj->children_names: This will return an array of all the names of child elements for $xmlobj. You can use this to step through all the children of a given element (see EXAMPLES), although multiple elements of the same name will not be identified. Use 'children()' instead.
$xmlobj->value: If the element represented by $xmlobj contains any PCDATA, this method will return that text data.
$xmlobj->attribute('NAME'): This returns the text for an attribute NAME of the XML element represented by $xmlobj.
$xmlobj->attributes: This returns a hash of key/value pairs for all elements in element $xmlobj.

EXAMPLES

Given this XML document:

  <files>
    <file type="symlink">
      <name>/etc/dosemu.conf</name>
      <dest>dosemu.conf-drdos703.eval</dest>
    </file>
    <file>
      <name>/etc/passwd</name>
      <bytes>948</bytes>
    </file>
  </files>

You can then interpret the tree as follows:

  my $parser = new XML::LibXML;
  my $xmlobj = new XML::SimpleObject::LibXML ($parser->parse_string($XML));

  print "Files: \n";
  foreach my $element ($xmlobj->child("files")->children("file"))
  {
    print "  filename: " . $element->child("name")->value . "\n";
    if ($element->attribute("type"))
    {
      print "    type: " . $element->attribute("type") . "\n";
    }
    print "    bytes: " . $element->child("bytes")->value . "\n";
  }

This will output:

  Files:
    filename: /etc/dosemu.conf
      type: symlink
      bytes: 20
    filename: /etc/passwd
      bytes: 948

You can use 'children()' without arguments to step through all children of a given element:

  my $filesobj = $xmlobj->child("files")->child("file");
  foreach my $child ($filesobj->children) {
    print "child: ", $child->name, ": ", $child->value, "\n";
  }

For the tree above, this will output:

  child: bytes: 20
  child: dest: dosemu.conf-drdos703.eval
  child: name: /etc/dosemu.conf

Using 'children_names()', you can step through all children for a given element:

  my $filesobj = $xmlobj->child("files");
  foreach my $childname ($filesobj->children_names) {
      print "$childname has children: ";
      print join (", ", $filesobj->child($childname)->children_names), "\n";
  }

This will print:

    file has children: bytes, dest, name

By always using 'children()', you can step through each child object, retrieving them with 'child()'.

AUTHOR

Dan Brian <dan@brians.org>

POD ERRORS

Hey! The above document had some coding errors, which are explained below:

Around line 150:: '=item' outside of any '=over'
Around line 195:: You forgot a '=back' before '=head1'