Parsing DMOZ XML files

Hello all,

I'm a newbie to the forum here and a newbie to xml (but I did read the book but you still need to "type slowly" please so I can understand . I am trying to mine the data from the dmoz rdf files that they provide for the categories and links. They provide a small "sample" file (which is what I am working with) from http://rdf.dmoz.org/rdf/structure.example.txt.

But I wasn't joking when I said I read the book. It is a book on using xml and php together and I copied a script out of there (see below) that, so far, parses other xml files but doesn't touch the dmoz one. I get the error message Warning: xmldocfile(): xmlParsePI : no target name in /home/bungeebo/public_html/xml_test/run_test3.php on line 3

Warning: xmldocfile(): Start tag expected, '<' not found in /home/bungeebo/public_html/xml_test/run_test3.php on line 3
error in xml doc



This is going to be quite a bit of code, but is probably the best way to figure it out. I color coded below

1) in green text the code of the php page parsing the xml, that produces the error when used on the subject dmoz data. The only change I make is the file name in line 2 of the two different xml files it is looking at (the next line 3 is referenced in the error msg). The file name used below (dmoz_cat_ex.xml) produces the error while "test.xml" doesn't.
2) in blue text the code of the xml that works (test.xml) and
3) in red text a section of the code that causes the error (dmoz_cat_ex.xml). The rest of the code is the same code as on http://rdf.dmoz.org/rdf/structure.example.txt).

<?php
$xml_file = "dmoz_cat_ex.xml";
if (!$doc = xmldocfile($xml_file))
{
die ('error in xml doc');
}
$root = $doc->root();
$children = get_children($root);
$elementCount = 1;
print_tree($children);

function print_tree($nodeCollection)
{
global $elementCount;
echo '<ul>';
for($x=0; $x<sizeof($nodeCollection); $x++)
{
$elementCount++;
echo '<li>' . $nodeCollection[$x]->tagname;
$nextCollection = get_children($nodeCollection[$x]);
print_tree($nextCollection);
}
echo '</ul>';
}

function get_children($node)
{
$temp = $node->children();
$collection = array();
for($x=0; $x<sizeof($temp); $x++)
{
if($temp[$x]->type == XML_ELEMENT_NODE)
{
$collection[] = $temp[$x];
}
}
return $collection;
}
echo 'Total number of elements : ', $elementCount;
?>



<?xml version="1.0" encoding="ISO-8859-1"?>
<rss version="2.0">
<channel>
<title>CBC | Top Stories News</title>
<link>http://www.cbc.ca/news/</link>
<description>FOR PERSONAL USE ONLY</description>
<language>en-ca</language>
<lastBuildDate>Fri, 12 Jan 2007 16:28:57 EST</lastBuildDate>
<copyright>Copyright: (C) Canadian Broadcasting Corporation, http://www.cbc.ca/aboutcbc/discover/termsofuse.html#Rss</copyright>
<docs>http://www.cbc.ca/rss/</docs>
<image>
<title>CBC.ca</title>
<url>http://www.cbc.ca/rss/image/cbc_144.gif</url>
<link>http://www.cbc.ca</link>
</image>
<item>
<title>Pakistan objects to U.S. claims it shelters leaders of al-Qaeda</title>
<link>http://www.cbc.ca/world/story/2007/01/12/pakistan-alqaeda-070112.html?ref=rss</link>
<author>CBC</author>
<pubDate>Fri, 12 Jan 2007 12:30:21 EST</pubDate>
<description>Pakistani officials have sharply rejected U.S. claims that the country is harbouring senior al-Qaeda leaders and serving as a nerve centre controlling terror operations.</description>
</item>
<item>
<title>Extreme wind chill shuts down Manitoba schools</title>
<link>http://www.cbc.ca/canada/manitoba/story/2007/01/12/mba-cold.html?ref=rss</link>
<author>CBC</author>
<pubDate>Fri, 12 Jan 2007 11:14:31 EST</pubDate>
<description>Classes were cancelled at many schools Friday as most of southern Manitoba woke up under a deep freeze, with a wind chill making it feel like -48 C.</description>
</item>
<item>
<title>Ontario man accused of bilking investors of $8M</title>
<link>http://www.cbc.ca/money/story/2007/01/12/spencer.html?ref=rss</link>
<author>CBC</author>
<pubDate>Fri, 12 Jan 2007 15:32:06 EST</pubDate>
<description>Police in Toronto have issued a Canada-wide warrant for the arrest of a 25-year-old man who they say defrauded friends and relatives of $8 million.

</description>
</item>
<item>
<title>Beckham set to invade America</title>
<link>http://www.cbc.ca/sports/soccer/story/2007/01/12/david-beckham.html?ref=rss</link>
<author>CBC</author>
<pubDate>Fri, 12 Jan 2007 14:33:15 EST</pubDate>
<description>David Beckham is one of the most famous athletes in the world, but he's hardly a household name in the United States. He has five years to change that.</description>
</item>
<item>
<title>Water isn't only source of Montezuma's revenge</title>
<link>http://www.cbc.ca/consumer/story/2007/01/12/travellers-diarrhea.html?ref=rss</link>
<author>CBC</author>
<pubDate>Fri, 12 Jan 2007 15:29:28 EST</pubDate>
<description>Many Canadians, adhering only to the old travellers' maxim of 'don't drink the water,' are putting themselves at risk by ignoring other potential diarrhea triggers, a new study suggests.</description>
</item>
</channel>
</rss>





<? xml version='1.0' encoding='UTF-8' ?>

<RDF xmlns:r="http://www.w3.org/TR/RDF/"
xmlns:d="http://purl.org/dc/elements/1.0/"
xmlns="http://dmoz.org/rdf">

<!-- Generated at 2004-05-04 01:05:15 GMT on dust -->

<Topic r:id="Top">
<catid>1</catid>
<d:Title>Top</d:Title>
<lastUpdate>2004-04-13 23:40:59</lastUpdate>
<narrow r:resource="Top/Arts"/>
<narrow r:resource="Top/Shopping"/>
<narrow r:resource="Top/Science"/>
<narrow r:resource="Top/Games"/>
<narrow r:resourc

 

I know very little about XML and RDF, but I don't believe they are the same thing (the ODP data is the latter). You may find the links here useful:
http://dmoz.org/Computers/Internet/...rectory_Project/Use_of_ODP_Data/Upload_Tools/