There’s already a Ruby upgrade script to create a WordPress compatible WXR file for importing which includes all posts, comments and categories from Typo. I needed to modify the Ruby script slightly to get working with the version of Typo I had installed.

Exporting Typo blog content to WordPress WXR

The Ruby script needs to be placed into the script directory of the Typo application root and then run under the production Rails environment:

RAILS_ENV=production ruby script/wp_export.rb > blog.wxr

Installing WordPress

Simply follow the basic WordPress install guide after downloading the latest software (version 2.7 at the time of writing). The pre-requisites for WordPress are PHP 4.3 or newer and MySQL 4.0 or greater.

Import existing content

Once WordPress is installed, log in to the admin section and select Import from the Tools menu. Choose the WordPress option from the list (Import posts, pages, comments, custom fields, categories, and tags from a WordPress export file). You’ll need to select the blog.wxr file created by the Ruby script and then click Upload file and import. That should recreate your existing Typo blog content (and comments), you may be asked to map the Typo user(s) to WordPress accounts.

With the content installed, the final change required is to setup the Permalink Settings from Settings > Permalinks. Select the Day and name option (giving URLs such as http://www.slashdotdash.net/2009/01/02/sample-post/). You may need to manually edit or create the .htaccess file to get the rewrite rules working.

# .htaccess

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]

With this working you should find that the standard Typo permalinks (such as http://www.slashdotdash.net/articles/2009/01/02/sample-post/) will now redirect to the corresponding WordPress blog entry, ensuring no broken links when switching from Typo to WordPress.

Known Issues

You’ll probably have a problem with RSS feed readers creating duplicates of the last 10 posts (depending upon your “Syndication feeds show the most recent” settings) since the post URLs and GUIDs will have changed.

One quick note to anyone experiencing the following problem with Typo running on Debian Linux:

Lost connection to MySQL server during query

The recommended ‘fix’ is to gem install mysql. Doing that on a Debian machine will result in numerous errors unless you also do the following:

$ apt-get install libmysqlclient10-dev
$ gem install mysql

(Thanks to the owner of this blog for the pointer, found via google).

Initially I had a problem with the new Typo gem (installing on a Debian server). This was caused by the sqlite3 gem dependency and was resolved quite simply.

Building native extensions.  This could take a while...
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of
necessary libraries and/or headers.  Check the mkmf.log file for more
details.  You may need configuration options.

Requires the sqlite3 development headers, which were an apt-get command away.

apt-get install sqlite3 sqlite3-ruby libsqlite3-dev
gem install sqlite3-ruby

Install Typo 4

gem install typo
mysqldump <typo_db_name> -uusername -p > backup.sql
mv /old/blog/location /old/blog_bak
typo install /your/path

Copy over database.yml to new location (and also .htaccess file), then update the database.

rake migrate

Restart the webserver and voila.

In Production mode the default Typo cache setup is to write out static .html files for pages, categories and archive views.

This is invaluable when running a live system as Rails is not even invoked allowing Apache to respond to the request very efficiently, but quite annoying if you haven’t yet realised this is happening! It certainly caught me out, even when running through ruby script/server -e development the “old” page was being served since the .html file was still present.

ls -l public/articles/2006/02/11/another-weblog.html
-rw-r--r--  1 www-data www-data 6901 Feb 16 00:03 public/articles/2006/02/11/another-weblog.html

Behind the scenes Typo will deal with refreshing the cached pages for us, but this refresh will only be triggered when changes are made.

Hope this helps someone.