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HTML::TreeBuilder::XPath - add XPath support to HTML::TreeBuilder


  use HTML::TreeBuilder::XPath;
  my $tree= HTML::TreeBuilder::XPath->new;
  $tree->parse_file( "mypage.html");
  my $nb=$tree->findvalue( '/html/body//p[@class="section_title"]/span[@class="nb"]');
  my $id=$tree->findvalue( '/html/body//p[@class="section_title"]/@id');

  my $p= $html->findnodes( '//p[@id="toto"]')->[0];
  my $link_texts= $p->findvalue( './a'); # the texts of all a elements in $p
  $tree->delete; # to avoid memory leaks, if you parse many HTML documents 


This module adds typical XPath methods to HTML::TreeBuilder, to make it easy to query a document.


Extra methods added both to the tree object and to each element:

findnodes ($path)

Returns a list of nodes found by $path. In scalar context returns an Tree::XPathEngine::NodeSet object.

findnodes_as_string ($path)

Returns the text values of the nodes, as one string.

findnodes_as_strings ($path)

Returns a list of the values of the result nodes.

findvalue ($path)

Returns either a Tree::XPathEngine::Literal, a Tree::XPathEngine::Boolean or a Tree::XPathEngine::Number object. If the path returns a NodeSet, $nodeset->xpath_to_literal is called automatically for you (and thus a Tree::XPathEngine::Literal is returned). Note that for each of the objects stringification is overloaded, so you can just print the value found, or manipulate it in the ways you would a normal perl value (e.g. using regular expressions).

findvalues ($path)

Returns the values of the matching nodes as a list. This is mostly the same as findnodes_as_strings, except that the elements of the list are objects (with overloaded stringification) instead of plain strings.

exists ($path)

Returns true if the given path exists.


Returns true if the element matches the path.

find ($path)

The find function takes an XPath expression (a string) and returns either a Tree::XPathEngine::NodeSet object containing the nodes it found (or empty if no nodes matched the path), or one of XML::XPathEngine::Literal (a string), XML::XPathEngine::Number, or XML::XPathEngine::Boolean. It should always return something - and you can use ->isa() to find out what it returned. If you need to check how many nodes it found you should check $nodeset->size. See XML::XPathEngine::NodeSet.


HTML::TreeBuilder's as_XML output is not really nice to look at, so I added a new method, that can be used as a simple replacement for it. It escapes only the '<', '>' and '&' (plus '"' in attribute values), and wraps CDATA elements in CDATA sections.

Note that the XML is actually not garanteed to be valid at this point. Nothing is done about the encoding of the string. Patches or just ideas of how it could work are welcome.


Same as as_XML, except that the output is indented.





Michel Rodriguez, <>


Copyright (C) 2006 by Michel Rodriguez

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself, either Perl version 5.8.4 or, at your option, any later version of Perl 5 you may have available.