Turn on mod_deflate!

This article is a quick bit of advice for those developer-turned-web-admins out there.
This article is specifically about the Apache "httpd" web-server, but the same advice applies to other web-servers.

While looking into Javascript compressors (minfiers and packers), I bumped into HTTP compression. I knew about HTTP compression, but it wasn't something I'd really thought about.

After a quick read-up at Wikipedia and after scanning a few HOW-TOs, I checked out the web-server that I maintain at my place of work. What do you know, but it (Ubuntu 9.x + Apache2.2) already came with mod_deflate.c enabled and marginally configured.

According to Danny Vogler's advice, I changed the following:

<IfModule mod_deflate.c>
  AddOutputFilterByType DEFLATE text/html text/plain text/xml
</IfModule>

... into this: (modifications in red)

<IfModule mod_deflate.c>
        AddOutputFilterByType DEFLATE text/html text/plain text/xml application/javascript application/x-javascript text/css
</IfModule>

The web-server will now attempt to compress Javascript and CSS content-types—if the client's web-browser supports it, of course.


I then turned my browser to an internal reports page, one that uses jQuery, jQuery-UI, and a (custom) jQuery-UI theme. Counting the site's own CSS theming (including media=print stylesheet), there are four stylesheets and four javascript files attached.

With text/html compression already turned on, the whole mess of content came out to 222,745 Bytes (around 218 KB), including pictures. With text/css and application/javascript content-types being compressed, the content came down to 69043 Bytes (67 KB)—only 30% of the original size! ... Yep, it made my day.