Migrating from Drupal to WordPress

Well, it finally happened. After months of frustration with Drupal as a blog tool, I gave up and decided it was time to move over to WordPress.

I’m sure as a CMS system Drupal can be quite wonderful, but for running and managing a simple blog site, I have yet to come across a better platform than WordPress.

However, the migration of the database content from one system to another had its ups and downs. Fortunately for me, not many people read this blog, so I only had to migrate the post data from one database to the other.

Below is the script I wrote to do so, in the hopes that this might save someone else the hassle of writing it themselves.

P.S. This was for a Drupal 6 to WordPress 2.8.2 migration. If it doesn’t work for you because you are working with different versions of either Drupal or WordPress, drop me a line and I will try to modify it for you.

<?php
/**
 * Setup database constants
 */
define('DRUPAL', 'phpdevec_drpl1');
define('WORDPRESS', 'phpdevec_wordpress');
define('URL', 'http://www.php-developer.co.za/');
/**
 * Setup server constants
 */
define("SERVER", "localhost");
define('USER', 'username');
define('PASSWORD', 'password');

/**
 * debug function outputs data
 */
function debug($data){
	echo '<pre>';
	print_r($data);
	echo '</pre>';
}

/**
 * Connect to server and database
 */
function connect($db) {
	// database connection
	$conn = mysql_connect(SERVER, USER, PASSWORD);
	if (!$conn) {
		//connection to server failed
		die("Cannot connect to server");
		return false;
	}

	$dbSelected = mysql_select_db($db, $conn);
	if(!$dbSelected) {
		// database connection failed
		die("Cannot connect to database");
		return false;
	}
	return $conn;
}

/**
 * Close database connection
 */
function disconnect($conn){
	if ($conn){
		// connection exists to close
		if (!mysql_close($conn)){
			// database connection failed
			die("Cannot close database connection");
			return false;
		}
		return true;
	}
	// default return in case the original connection failed
	return true;
}

/**
 * Generic SQL SELECT, checks type
 * (SELECT, INSERT, UPDATE [DELETE])
 *
 * @param string $sql query
 * @param string $type object or assoc
 * @return mixed $return array of rows if select or true/false if insert/update/delete
 */

function sql($sql, $database, $type = 'assoc'){
	$return = '';

	// check database connection
	$connection = connect($database);
	if (!$connection){
		$return = false;
	}

	$sql = ltrim($sql);
	$query_type = substr($sql, 0, 6);

	// run query
	$rst = mysql_query($sql);

	if (!$rst){
		// query failed for some reason
		die("Error in MySQL query: " . $sql);
		$return = false;
	}else {

		if (strtoupper($query_type) == "SELECT"){
			// query was SELECT
			$return = array();
			$rows = mysql_num_rows($rst);

			switch($type) {
				case 'assoc' : // return as assoc array
					while($row = mysql_fetch_array($rst)) {
						// gather rows
						$return[] = $row;
					}
					break;
				default : //return as object
					while($row = mysql_fetch_object($rst)) {
						// gather rows
						$return[] = $row;
					}
			}
		}else {
			// query was INSERT, UPDATE OR DELETE
			$queryType = 'UPDATE';
			if (mysql_insert_id()){
				// query was INSERT
				$id = mysql_insert_id();
				$queryType = 'INSERT';
				$return = $id;
			}else {
				$rows = mysql_affected_rows();
				$return = $rows;
			}
		}
	}

	// disconnect from database
	disconnect($connection);

	//return rows / whether insert/update/delete successful
	return $return;
}

$sql = "SELECT n.*, nv.body as content FROM node as n LEFT JOIN node_revisions as nv on n.nid = nv.nid WHERE n.type = 'blog'";

$nodes = sql($sql, DRUPAL);

//debug($nodes);

$Nodes = array();

foreach ($nodes as $node){
	$nId = $node['nid'];
	$sql = "SELECT * FROM comments WHERE nid = '$nId'";
	$comments = sql($sql, DRUPAL);
	$node['comments'] = $comments;
	$Nodes[] = $node;
}

//debug($Nodes);

foreach ($Nodes as $node){
	//publish draft

	$two_hours = 2*3600;
	$date = $node['created'];
	$gmt_date = $date - $two_hours;
	$modified = $node['changed'];
	$gmt_modified = $modified - $two_hours;

	$post_date = date('Y-m-d H:i:s', $date);
	$post_date_gmt = date('Y-m-d H:i:s', $gmt_date);
	$post_modified = date('Y-m-d H:i:s', $modified);
	$post_modified_gmt = date('Y-m-d H:i:s', $gmt_modified);

	$post_title = mysql_escape_string($node['title']);
	$post_content = mysql_escape_string($node['content']);
	$post_name = strtolower(str_replace(array(' ', '.'), array('-', ''), $post_title));

	$status = $node['status'] == '1' ? 'publish' : 'draft';

	$sql = "INSERT INTO phpdevec_posts SET
			post_author = 1,
			post_date = '$post_date',
			post_date_gmt = '$post_date_gmt',
			post_content = '$post_content',
			post_title = '$post_title',
			post_status = '$status',
			comment_status = 'open',
			ping_status = 'open',
			post_name = '$post_name',
			post_modified = '$post_modified',
			post_modified_gmt = '$post_modified_gmt',
			post_parent = '0',
			menu_order = '0',
			post_type = 'post',
			comment_count = 0";

	$id = sql($sql, WORDPRESS);

	if (!$id){
		die('An error occured adding the data to the database');

	}

	/*
	if (!empty($comments)){
		foreach ($comments as $comment){
		}
	}
	*/

	$guid = URL . "?p=$id";

	$sql = "UPDATE phpdevec_posts SET guid = '$guid' WHERE ID = '$id'";

	$updated_rows = sql($sql, WORDPRESS);

	if (!$updated_rows){
		die('An error occured updating record no '. $id);
	}
}