The New York Times has released a modified xsl module for php5 which caches xsl transformations. I just built it on ubuntu and debian:
apt-get install php5-dev libxslt1-dev wget http://code.nytimes.com/downloads/xslcache.tar.gz tar -xzvf xslcache.tar.gz phpize./configure --with-xslcache=/usr/lib/ --with-xsl-exsl-dir=/usr/lib/ make cp modules/xslcache.so /usr/lib/php5/20060613+lfs/ cp /etc/php5/conf.d/xsl.ini /etc/php5/conf.d/xslcache.ini vim /etc/php5/conf.d/xslcache.ini
Cool. I got it to work with nexista, albeit a little funkified. It seems it can't accept a DOM Document like the regular XSLT processor class can, I had to save the xsl template after it had been loaded and entities transformed, and then have the XSLT object load in the file. Strange, but it worked, and I actually think this might be the right way to go - cache the xsl file with its entities converted and be done with it.
This extension is actually very nice. I agree with some of their assumptions - that the XML data in an XSL transformation is likely to change, not the stylesheet. And the cache is set to expire when the modification time of the source file is changed. Very good. As I mentioned earlier, I have to use a DOM Document to convert some entities prior to the xsl transform, so I'm saving a temp file before loading it with the XSLTCache object. This requires another cache check of course.
If you've been reading Docunext for awhile, I'll all about the caching. I try to cache database queries, php optcode, rendered pages, gzipped content, and even employ client caches. Why? Its by far the best performance boost available!
My results? Nexista is showing up to a 25% performance increase, or in other words, a page taking 0.2 second to load only takes 0.15 seconds to load after the XSL document has been cached.
php5-xsltcache php5-xsltcache/DEBIAN php5-xsltcache/DEBIAN/control php5-xsltcache/etc php5-xsltcache/etc/php5 php5-xsltcache/etc/php5/conf.d php5-xsltcache/usr php5-xsltcache/usr/lib php5-xsltcache/usr/lib/php5 php5-xsltcache/usr/lib/php5/20060613+lfs
Package: php5-xsltcache Version: 5.2.3 Section: web Priority: optional Architecture: i386 Depends: php5-common (>=5.2), php5-xsl Maintainer: Albert Lash Description: PHP 5 XSLTCache Similar to php5-xslt, php5-xsltcache caches xsl documents in permanent memory, but keeps an eye on modification time of referenced file. See: http://code.nytimes.com/projects/xslcache
UPDATE November 1, 2007: Apache can do this stuff too! See my post on mod_transform!