TEK PERSPEKTIVE: Wordpress Plugin: WP Super Cache on Ubuntu 10.04

I am in what is perhaps a unique situation... I started using Blogger a while back for my personal blog, but my business site is hosted at GoDaddy.com and uses WordPress 3.1.1. I've found WordPress to be an excellent web platform, and at this point I'm debating continuing to use Blogger, but I suppose I'll figure that out at some point later... One issue I ran into was performance of my business website using WordPress. After some research, I decided to try out the WP Super Cache plugin in order to improve response times for page requests. Funnily enough, it turned out to be much easier to install and configure the WP Super Cache plugin on GoDaddy.com than on my local server. Of course, by the time I installed on GoDaddy I had spent some time with it and was a bit more familiar with it. That said, the GoDaddy.com folks seem to have all permissions and pre-requisites in place in order to use this plugin, because it installed and activated without any issues at all.

I set up a WordPress test environment on a machine running Ubuntu 10.04 so that I can implement and preview all changes prior to rolling them out live. There are a lot of instructions, notes, and other items related to installing the WP Super Cache plugin, however nothing seemed to work for my particular configuration. I ended up having to do quite a bit of searching around to figure out how to get everything to work and so I decided to document what I found to work on my system. My server config:

Ubuntu 10.04
WordPress 3.1.1
Apache2 (standard install via synaptic)
New install of WP Super Cache plugin (I did not have the WP Cache plugin)

STEP 1 - Download WP Super Cache plugin

You can download it here, or within the WordPress management console.

STEP 2 - Extract plugin files to WordPress Plugin directory and set permissions

The WordPress plugin directory is located in

../wordpress_root/wp-content/plugins

Set permissions via the command line:

user@host:$ cd ../wordpress_root/wp-content/plugins
user@host:$ sudo chmod -R 0755 wp-super-cache

STEP 3 - Install required modules for Apache

rewrite
mime (this was already installed on my system)
headers
expires

The command to install these modules is

user@host:$ sudo a2enmod rewrite

After installing all required modules you will need to restart Apache, however wait until after the following tasks to do this, as otherwise you'll have to do it twice.

STEP 4 - Add configuration entries for Apache

Edit the following files located in /etc/apache2/sites-available:

wordpress
default* - Make sure you edit this file as well as the wordpress file, I failed to do so initially and it took me quite a bit of troubleshooting before I made the same changes to default and got things to work.

I just executed the following command to edit in gedit:

user@host:$ sudo gedit /etc/apache2/sites-available/wordpress

Here's what I have at the top of the wordpress file:

<virtualhost *:80="">
 ServerAdmin webmaster@localhost

 DocumentRoot /var/www/wordpress
 <directory>
  Options FollowSymLinks
  AllowOverride All
 </directory>
 <directory var="" www="">
  Options Indexes FollowSymLinks MultiViews
  AllowOverride All
  Order allow,deny
  allow from all
 </directory>

Here's what I have at the top of the default file:

<virtualhost *:80="">
 ServerAdmin webmaster@localhost

 DocumentRoot /var/www
 <directory>
  Options FollowSymLinks
  AllowOverride All
 </directory>
 <directory var="" www="">
  Options Indexes FollowSymLinks MultiViews
  AllowOverride All
  Order allow,deny
  allow from all
 </directory>
</virtualhost>

Now restart apache:

user@host:$ sudo /etc/init.d/apache2 restart

STEP 5 - Activate Permalinks within WordPress

The WP Super Cache plugin requires that "pretty links" be enabled in order to function. This is of course also beneficial for aesthetic reasons, as well as SEO, but is also a necessary step here. All you have to do is select something other than the default. You can either use one of the available options such as Day and Name or Month and Name. If you don't like any of the available options, see the WordPress Permalink documentation for some of the other variables to construct you own structure and put it into the custom field.

Permalink Settings in WordPress Admin Console

STEP 6 - Activate WP Super Cache plugin within WordPress and configure

Once you've completed all of the steps above, you should be able to activate the WP Super Cache plugin within the Plugin screen of the WordPress Admin Console and then enable caching.

Once you've activated the WP Super Cache plugin go to the WP Super Cache Control Panel under Settings in the WordPress Admin Console. Select the radio button next to Caching On (Recommended)

Enable Caching in WP Super Cache Settings

Once you do this, if you scroll down the settings page, you will probably see a notification about needing to update the .htaccess file in the WordPress directory. Provided the permissions are correctly set in your root WordPress directory, WordPress should have generated an .htaccess file for you and inserted the appropriate entries when you changed your Permalinks setting to a custom definition. If you get error messages about .htaccess make sure that the following permissions are set on your WordPress directory:

user@host:$ sudo chown -R user:www-data [wordpress_root_directory_location]/wordpress
user@host:$ sudo chmod -R 0755 [wordpress_root_directory_location]/wordpress

Once that is done, WordPress should be able to update your .htaccess file without issue. Scroll down the settings page and look for a notification that your Mod Rewrite rules are out of sync and need to be updated. Click on the Update Rewrite Rules button and you should see a screen similar to that below.