owncloud – Cache Static Assets (CSS/Javascript)

To whom it might be useful,

I recently set up an owncloud instance for private use and found that the load time was abysmal. Showing the default “Files” page spends ~21 seconds for ~140 HTTP requests¹, even though my HTTP setup is already quite pimped (with SPDY and all). What is worse: The time does not reduce on subsequent visits. No cache-control headers are sent and all the Javascript and CSS resources are requested again. There is ETag and If-None-Match in place, so most of the requests just yield a 304 Not Modified response, but they still block the loading process. Which is even less understandable if you look at the requests: All Javascript and CSS resources are using a “?v=md5($owncloud_version)” cache buster, so they would be fully cacheable with no ill effects.

For a standard owncloud installation in /var/www with Apache: Open your /var/www/owncloud/.htaccess in a text editor and append the following lines (Update 2014-10-09 18:35 UTC: Add missing \ before .)

<IfModule mod_headers.c>
<FilesMatch "\.(css|js)$">
Header set Cache-Control "max-age=2592000, public"
</FilesMatch>
</IfModule>

then in a shell make sure that the headers module is enabled in Apache:

sudo a2enmod headers

and restart Apache as prompted by a2enmod.

The next time you load the owncloud web interface your browser will be told to cache the Javascript and CSS resources for 30 days, and the time after that it won’t request them again. The “Files” app load time dropped from 21 to 6 seconds for me – with 16 instead of ~140 requests.  That’s almost reasonable!

1. In Firefox: Press Ctrl-Shift‑Q to bring up the Network web developer tool to watch the drama unfold in its entirety. ↩