Following my post on Blog Bloat, I have finally gotten around to installing mod_concat. I asked my hosting provider ServInt to handle the upgrade to Apache 2.2.x, they did it in about 20 mins – thanks guys, you rock!
The actual installation of mod_concat was fairly simple thanks to the included instructions, though it lacked a few of the finer points, like needing to install the module into the Apache modules directory and modifying httpd.conf to include mod_concat, this is easily handled by adding the -i and -a flag. First grab the project out of SVN, then you can compile it.
prompt:$ svn checkout http://modconcat.googlecode.com/svn/trunk/ modconcat-read-only prompt:$ cd modconcat-read-only/mod_concat prompt:$ apxs -i -a -c mod_concat.c #Make sure the config file is working okay prompt:$ apachectl configtest #Then it's safe to restart and use the concat module prompt:$ apachectl -k graceful
That’s all it takes to get the module working with Apache 2.2.x. I setup a super simple test here to ensure mod_concat is working.
Optimizing WordPress K2 using mod_concat
Getting this Apache module working with WordPress and K2 wasn’t quite as simple as I was hoping. I ended up having to do more customization work than I desired. The issue with K2 is that many of the included JavaScript files, for handling the rolling archives and live search, have a .php extension that includes a gzip directive header. Additionally, the K2 files are nested so deep that mod_concat can’t handle it.
To deal with these short comings, I sourced the K2 JavaScript files and moved them to a root directory. Currently, the files to be concatenated are hard coded into the plugin. Perhaps a future revision will resolve this, however, I am more interested in testing out mod_jsmin and mod_deflate before I get around to this enhancement.
Here is the plugin code I wrote in order to use mod_concat with K2.
<?php /* Plugin Name: WP Mod Concat Description: This plugin leverage the Apache 2.2.x module mod_concat to combine a list of files into a single file Version: 0.1 Author: Gregory Tomlinson Author URI: http://gregorytomlinson.com/encoded/ */ remove_action('wp_head', 'wp_print_scripts'); add_action( 'wp_head', 'wp_mod_concat_optimzie' ); function wp_mod_concat_optimzie( $handles = false ) { $base_url = "http://gregorytomlinson.com/js/??"; $script_files = array("jquery_1_2_6.js", "k2.functions.js", "k2.livesearch.js", "k2.rollingarchives.js", "k2.slider.js", "k2.trimmer.js", "swfobject.js" ); echo '<script type="text/javascript" src="'. $base_url . join(",", $script_files) . '"></script>'; } ?>
By using remove_action(’wp_head’, ‘wp_print_scripts’);, I can stop WordPress from loading JavaScript files. I then replace the head script files with the concatenated version leveraging mod_concat, which produces a script tag that looks like the following.
<script type="text/javascript" src="http://gregorytomlinson.com/js/??jquery_1_2_6.js,k2.functions.js,k2.livesearch.js,k2.rollingarchives.js,k2.slider.js,k2.trimmer.js,swfobject.js"></script>You can learn more about mod_concat here.
The other drawback to mod_concat is it’s incapable of handling query parameters. I would like to be able to append a ?ver=1.1 in order to handle busting the browser cache, but the current version isn’t able to do this, maybe Ian can fix this 
That’s all it takes to use mod_concat. It’s probably not the ideal method to use with WordPress and K2, you may consider using PHP Speedy. Dave Artz runs down a list of other concatenation methods in this blog post.
