Updating WordPress via Phing

Here's what I'm using to upgrade WordPress:

A WordPress installation can be divided into three parts. The first part involves the core WordPress folders: wp-admin and wp-includes. You normally don't change anything in these folders, so upgrading them can just be a matter of deleting what you've got and replacing it.

The second part involves customized folders. The most important of these is wp-content, since it contains your site's theme and plugins, but you might have other folders that are similarly off-limits as far as upgrading is concerned. Whatever happens during the upgrade process, we don't want to touch this stuff.

The final part involves the PHP files at the root level of the site. These are mostly wp-* files that aren't changed, except for wp-config.php, which is.

Conveniently, the URL for the latest version of WordPress is always the same. I use curl to download it to /tmp because it allows me to pipe the download straight into tar. After deleting the core WordPress folders recursively, I rename wp-config.php and any other custom PHP files (in this example, share-via-email.php) with a .bak extension so that they'll be preserved during the subsequent wipeout of all PHP, HTML, and TXT files in the site root.

From this point, it's just a matter of copying in the new files and restoring the .bak files to their original name. Since the deletion process was restricted to known extensions, the only risk is in forgetting to make an exception for customized files. Version control can help with that, especially if you've accidentally deleted or overwritten something important.

I haven't accounted for .svn folders within the core folders. If you ran this target as-is, Subversion would complain about the sudden absence of .svn folders within the newly-copied wp-admin and wp-includes. This is a great reason for exploring other options like git that centralize all their stuff in a single directory.