Migrating From WordPress To Drupal

Before I began the transition from WordPress 2.0.3 to Drupal 4.7, I researched as much as I could. I hunted import scripts and I examined the mySQL databases from each. Over the course of the week before I made the move, I tested a combination of ways to get the conversion done, with as little of a disruption as possible. My requirements for the move were simple. I wanted all of my posts, comments and categories moved over, intact. Simple, right?

I found the current wp2drupal module and found that it did not pull category information so I made a couple of modifications and tweaks, and with a little effort I was able to import every post, comment, and category from WordPress to Drupal.

I am posting the following information as a guideline for those wanting to convert their WordPress blog into Drupal. While these instructions worked for me, they may not work for everyone, since every configuration is different. I just thought it would be nice to post the instructions so others might not have to search as hard as I did. If you are not familiar with mySQL or php, I do NOT recommend doing this yourself.

The first thing I did, of course, was setup up Drupal 4.7. I followed the basic installation procedures. Once the installation was complete I installed the pathauto module (which will provide the 'nice' urls that most WordPress users are accustomed too). I made sure to configure pathauto so the url's would reflect the same format as those used by my WordPress permalinks.

The second thing I did was download the wp2drupal module. For the record, the revision I used was 349.

I opened the module and made the following changes:

Line #189 (approximate):

$wp_table_prefix = variable_get('wp2drupal_wp_table_prefix', ");

was changed to:

$wp_table_prefix = variable_get('wp2drupal_wp_table_prefix', 'wp_');

Line #250 (approximate):

I added the following line to the module:

db_query("INSERT INTO term_node VALUES (" . $node_nid . "," . $wp_post->post_category .")");

I placed this line before this line:

$wp_comment_sql = "SELECT comment_author, comment_author_email, comment_author_url, comment_date, comment_content, comment_author_IP, comment_approved FROM " . $wp_prefix . "comments WHERE comment_post_ID = " . $wp_post->ID . " ORDER BY comment_date ASC";

I am sure I could have made some further changes to the module to make some things easier later in the process, but that's work for another day. hehe. I saved the changes I made to the module. I did not run the module at this time.

The next thing I did was import a few tables FROM the WordPress database INTO the Drupal database. The tables I imported were wp_posts, wp_comments, wp_post2cat, and wp_categories. I ran the following query to grab the category number from the post2cat table and plug it into the posts table (where I think it should have been in the first place).

Next, I set up a vocabulary item in Drupal named 'Category'.

It was then time to run the wp2drupal module. I had a bit of a problem with the importer timing out, because of the sheer volume of posts on my site (5,000) and my php settings. Once I tweaked things, the import worked flawlessly.

At this point of the conversion, I had successfully imported 5,000 posts and 3, 025 comments, but I still didn't have category names in my posts. I did, however, have those category numbers I wrote into the term_node table. It was time to match those numbers with the names that go with them.

I ran an export of the wp_categories table using phpMyAdmin, of which I copied out all of the lines like the following:

INSERT INTO `wp_categories` VALUES (1, 'Unclassified', 'unclassified', ", 0, 10);
INSERT INTO `wp_categories` VALUES (2, 'Personalized', 'personalized', ", 0, 268);
INSERT INTO `wp_categories` VALUES (3, 'FYI', 'fyi', ", 0, 231);
INSERT INTO `wp_categories` VALUES (4, 'Programming', 'programming', ", 0, 42);

I then manually edited these lines to reflect the following:

INSERT INTO `term_data` VALUES (1, 1,'Unclassified', ", 0);
INSERT INTO `term_data` VALUES (2, 1, 'Personalized', ", 0);
INSERT INTO `term_data` VALUES (3, 1, 'FYI', ", 0);
INSERT INTO `term_data` VALUES (4, 1, 'Programming', ", 0);

I made sure that each new number and title matched the old number and title. When I was done modifying the lines, I entered the SQL into phpMyAdmin, and each "category" was now imported into Drupal.

At this point I also created another set of insert statements,

INSERT INTO `term_hierarchy` VALUES (1, 0);
INSERT INTO `term_hierarchy` VALUES (2, 0);
INSERT INTO `term_hierarchy` VALUES (3, 0);
INSERT INTO `term_hierarchy` VALUES (4, 0);

for each category number (ie: if there are 17 categories, you would create a list like this from 1 through 17). I entered this SQL as well, as everything was in place.

A quick refresh of my page showed not only that I had successfully imported posts, comments, and categories into Drupal, but that each url matched the ones WordPress utilized previously.

And that's it. That was how I migrated from WordPress 2.0.3 to Drupal 4.7. I think I covered everything, but if something doesn't make sense, let me know, and I will edit this post accordingly.

Also, I would like to thank Vinny, for helping with the query to grab the category names in the first place.