Update to libxml2 in PHP - progress hath been acquired

Tuesday, June 5. 2007

Update to libxml2 in PHP - progress hath been acquired

Shortly after my last blog post, I got a very helpful email from Rob Richards, who offered to help me with my trials and tribulations. He took a quick look at the schema for package.xml, and a sample package.xml and was able to find two small tweaks to make parsing actually work (gasp). This changes everything. I am abandoning the creation of a relax NG schema in favor of the battle-tested xsd. The error messages for xsd validation are far clearer than the rng ones. For instance with this script:

<?php
$a = new DOMDocument();
$a->load('C:/development/pear-core/package2.xml');
libxml_use_internal_errors(true);
$a->schemaValidate('C:/devel/pearweb/public_html/dtd/package-2.0.xsd');
foreach (libxml_get_errors() as $error) {
echo "Line ", $error->line, ': ', $error->message, "\n";
}

and the <date> tag moved to the wrong location, I get this error:

Line 565: Element '{http://pear.php.net/dtd/package-2.0}date': This element is not expected. Expected is ( {http://pear.php.net/dtd/package-2.0}stability ).

Fantastic! The error actually tells you what the problem is and gives a useful clue on how to fix it - this is *exactly* what I need to strip out the thousands of lines of unnecessary schema validation code in Pyrus (hallelujah).

I still haven't worked out the problems I was having with rng, perhaps another update on this later.

Posted by Greg Beaver in PHP at 20:36 | Comments (4) | Trackbacks (0)

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BTW. have you ever noticed that the '-' character isn't allowed in the channel name. This is a bit strange, since '-' is a valid character in an URL.

#1 Arnold Daniels (Homepage) on 2007-06-06 17:31 (Reply)

- is not allowed in channel names because it makes parsing Package-Version or Package-State much more difficult in:

pear install channel://whatever.com/Package-1.2.3

This may be fixable in Pyrus since the memory footprint will be significantly smaller.

#1.1 Greg Beaver (Homepage) on 2007-06-07 11:32 (Reply)

Huh. c:/ ...

don't use full path

#2 blog php (Homepage) on 2007-06-12 01:43 (Reply)

channel:// is not a path (not c:/) it's an abstract url for identifying a unique channel/package.

#2.1 Greg Beaver (Homepage) on 2007-06-12 07:46 (Reply)

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