Mudy’s Blog

Update 2/24/2009: This method is deprecated. I wrote a plugin to rewite urls.
Update again: SimpleCDN is slower comparing to CloudFront, I moved all my link to CF. If you have problem copying files to S3, you can read this post.

WordPress is my favorite bloging software, with many builtin features and powerful plugins. WordPress.com, the blogging platform by automattic, has been using CDN for a long time. However there is no public available solution to make self hosted WordPress to use a CDN as well. Fortunately the php code itself is very clean to read, so it took me about 5 minutes to find where I should modify to fully integrate my new CDN address.

Before you proceed, please read my previous posts on how to use CNAME with SimpleCDN and how to process javascript and css files for WordPress. Make sure your SimpleCDN’s CNAME and bucket working properly. I used a mirror bucket which points to my blog address, that is probably the simplest way to mirror your static assets. And use ‘-s1′ pre-url to insure client side cache working, because SimpleCDN does not use 304 not modified http header at all. I used bucket name ’s.mudy.info’ for my own blog.

Once your DNS full propagated, open your favorite text editor open following 3 files.

‘wp-includes/class.wp-scripts.php‘: near line 75, change

$src = $this->base_url . $src;

to

$src = 'http://yourcdnbucketname' . $src;

There is no trailing slash after your bucketname. If you want to make sure client browser always use cached version, you can also comments out the following line.

// $src = add_query_arg('ver', $ver, $src);

But this change may break WordPress upgrade.

‘wp-include/class.wp-styles.php‘: near line 79, do the same change as above.

‘wp-include/theme.php‘: near line 504, change

return apply_filters('theme_root_uri', content_url('themes'), get_option('siteurl'));

to

return 'http://yourcdnbucketname/wp-content/themes';

That’s it. Now clean your cache and test your blog.

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Yejun Web cdn, optimization, simplecdn, wordpress