[wp-hackers] compression and caching

[Weston Ruter]

Hi all, I'm new here. Micah invited me to join in on the discussion.

I just read most of the messages in this thread, and I see most of them are
debating the merits of compressing (gzipping) responses. Regarding scripts
alone, just concatenating the enqueued scripts and minifying them will
result in drastic speedups without gzipping at all. For example, I recently
a WordPress site built by a reputable company that had 50(!) external
JavaScript files. If these were all concatenated together and
minified/optimized, then there would potentially be only one download. As an
added bonus, this optimized script could be gzipped and even more
importantly be served with a far-future expires header.

I have been developing a plugin called “Optimize Scripts” which does just
this. As the plugin page states, it:

   1. Respects head and footer groups.
   2. Minifies code using Google's Closure Compiler.
   3. Caches the concatenated/minified code and rebuilds it only when one of
   its source scripts expires or changes. The optimizescripts_expires filter
   is provided which allows the far-future expires time to be forced.
   4. Filename for concatenated/minified script is the md5 of all the
   handles concatenated together (thus if an additional handle is provided, a
   new concatenated script is generated).
   5. Provides a filter to limit which scripts get concatenated (i.e. jQuery
   on ajax.googleapis.com should be left alone); by default, all scripts on
   local host are concatenated, and remote scripts are left alone.
   6. Removes the default 'ver' query parameter which WordPress adds to
   every script src if no version argument is supplied on
   wp_enqueue/register_script: this is important for Web-wide caching of
   scripts loaded from ajax.googleapis.com, for example. When registering
   new scripts, pass the filemtime in as the version so that whenever a file
   changes, the concatenated script will be regenerated.
   7. Script optimization can be delegated to a scheduled cron job so that
   the server does not periodically respond slowly to visitors.

Read more and see examples on the plugin page:
http://wordpress.org/extend/plugins/optimize-scripts/

This plugin also relies on server configuration in that a far-future expires
header must be set, or otherwise the plugin will abort concatenation.
(However, the optimizescripts_expires filter mentioned above is a workaround
for this.)

I'm eager to hear what you all think about this approach and if would be
good to include in WordPress core so that it can be fast by default in how
it serves scripts.

Weston


*William Canino* wrote at *Mon Dec 28 21:22:29 UTC 2009*:

> Let me share with you guys my .htaccess file. I got more gains with
>
> this config in my experience than minifying and concatenating on the
> fly hereby killing the CPU of my shared host.
>
> # Far Expires
> FileETag All
> ExpiresActive On  # enable expirations
> ExpiresByType text/javascript "access plus 5 weeks"
>
>
> ExpiresByType application/x-javascript "access plus 5 weeks"
> ExpiresByType application/javascript "access plus 5 weeks"
> ExpiresByType text/css "access plus 5 weeks"
>
> # Javascript and CSS Gzipping
>
>
> # copied from http://zuble.blogspot.com/2007/02/compressed-js-and-modrewrite.html
> <FilesMatch "\\.js.gz$">
>
>   ForceType text/javascript
>
>   Header set Content-Encoding: gzip
> </FilesMatch>
> <FilesMatch "\\.js$">
>   RewriteEngine On
>   RewriteCond %{HTTP:Accept-Encoding} gzip
>   RewriteCond %{HTTP_USER_AGENT} !".*Safari.*"
>
>
>   RewriteCond %{REQUEST_FILENAME}.gz -f
>   RewriteRule (.*)\.js$ $1\.js.gz [L]
>   ForceType text/javascript
> </FilesMatch>
> <FilesMatch "\\.css.gz$">
>   ForceType text/css
>   Header set Content-Encoding: gzip
>
>
> </FilesMatch>
> <FilesMatch "\\.css$">
>   RewriteEngine On
>   RewriteCond %{HTTP:Accept-Encoding} gzip
>   RewriteCond %{HTTP_USER_AGENT} !".*Safari.*"
>   RewriteCond %{REQUEST_FILENAME}.gz -f
>
>
>   RewriteRule (.*)\.css$ $1\.css.gz [L]
>   ForceType text/css
> </FilesMatch>
>
> I then saved a minified+gzipped version of each css and js on the
> respective directories.
>
> Don't joke -- I *have* killed a shared hosting CPU before by
>
>
> dynamically concatenating, minifying and compressing assets.
>
>