I wont go into too much detail here as to how we went about it, I simply do not have time today, and I know that people are awaiting this script.

I decided at the last minute to add comments to the import process, for the comment systems I chose both the Jom Comment module (Commercial and is integrated with the My Blog component http://azrul.com), and the Joomla! Comments module.

If you have other comment modules that you would like added to this list, please let me know and I will do my best to also write conversion for them. Personally if you can afford it I advise going with Jom Comments, it has a lot more to offer in general and is a lot cleaner all around.

With the content and comments import, there have also been some changes added to the config file. I have added settings for the batch import, the comment system you wish to import into and if you want comments added at all. The config file is first, then the content file.
I have not completed the database table clean-up at this stage, but I will be writing a GUI and clean system before actually releasing this as a full package, and at that stage will add the database clean-up.
Continue Reading ->

I thought that i should touch quickly on recursion as it is something that is needed for the below tutorial on creating a conversion script for Wordpress to Joomla

Recursive functions, are functions that call upon themselves repeatedly, in the example in the previous post the function updateCategory is a recursive function

function updateCategory($category, $newParentID)
{
	global $db, $jb, $wp_prefix, $j_prefix;
	$children = $db->get_results("SELECT t.term_id as term_id, t.name as tname, t.slug as tslug, tt.description as description, tt.parent as parent FROM ".$wp_prefix."terms AS t INNER JOIN ".$wp_prefix."term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('category') and parent=".$category."  ORDER BY t.name");
 
	foreach($children as $child) {
		updateCategory($child->term_id, $newParentID);
		//Check if we are insterting into 1.5 or 1.0.x
		if($j_version=='1.5') {
			//Insert the latest category 
			$jb->query("insert into ".$j_prefix."categories (title, alias, section, description, published) Values('".$child->tname."', '".$child->tslug."', '".$newParentID."', '".$child->description."', 1)");
		}
		else
		{
			$jb->query("insert into ".$j_prefix."categories (title, name, section, description, published) Values('".$child->tname."', '".$child->tslug."', '".$newParentID."', '".$child->description."', 1)");
 
		}
 
		//
		// Insert into our temp storage/reference table
		//
		$jb->query("insert into jos_wp_category_map (wp_cat_id, jos_cat_id, jos_sec_id) values(".$child->term_id.", ".$jb->insert_id.", ".$newParentID.")");
 
	}
 
}

This function uses a recordset of data from the database, it then goes through each of the categories, sub-categories and inserts them in the database in a new level to it’s previous position, the function then calls itself again to check if the current record has children records.

This is a classic example of why recursion is useful and whilst not perfect coding, it does show the usefulness when you need to run a function for deep levels of information and in particular when you do not know how deep you need to go.

So to re-iterate, a recursive function simply calls itself multiple times.

I hope this helps and I hope you find new useful ways to use this, once learning recursive functions, it adds a whole new level to your coding and can cut the amount of lines of code you need to write in half.

In the first part of this series we looked at setting up the basics of the conversions script, config files, user imports and discussed the importance of planning each stage out and how to go about it.

In this section we will be looking at importing the categories from Wordpress into Joomla. You will be glad to know this part of the series should be a bit shorter to read. Though no less complicated, it is also the 3rd step of the conversion, and we only need to run the article import and the clean up after this.

One of the problems with the conversion is that Wordpress and Joomla, as you would expect do things differently, this is comes to light in the categories import and presents us with the first big decision of the entire import process. The problem is, that whilst in Wordpress all Categories can be a parent without a child, Joomla requires that you have both a section and a category.
This leads us to make the choice whether to create a single “placeholder” parent section, and then make all of our categories from Wordpress into Joomla categories, or whether to create all our Wordpress categories as Joomla sections and those without children, create a placeholder category under the section.
Finally, Joomla only allows for 2 levels, Section >> Category, whereas Wordpress allows, for children to be parent categories themselves giving a never ending hierarchy so we aren’t going to be able to have say “technology” >> “Apple” >> “iPhone” so we have yet another decision to make, we will either have to cut out the middle man, make the middle category section, or make them all sections with a generic “general” category beneath them.
In this case I have decided to include a function that will check the following:

• If the category is a parent
• If the category has children
• How many children and levels it has
• Restructures the categories, to either have child, to be child and brings them into a singular line

As such you will likely need to manage and change these through the Joomla Administrator UI after the conversion, as you may wish to get rid of some of the parents, (i.e. Technology >> Apple >> iPhone becomes Technology >> iPhone therefore either eliminating the need of the Apple category or making it obsolete in this example.

This scheme should work, it also means that each singular parent category is going to need a child, so lets say you had a category called “Foo”, we will then create a category under it called “bar” we will in this example however, name the category the same as the section, this will be somewhat confusing when you first look at it, however it at least maintains some sanity and continuance from your Wordpress set up.

If you want to make life easier it may be worth editing your category structure in Wordpress before the conversion this, will make life easier at the end of the day. We will no matter what repeat the section as a category, so it works in the same way as Wordpress.

I hope that wasn’t too confusing, it’s really quite simple, it’s just a matter of coming up with the correct or best worked solution for you. This is how I have decided is the cleanest way to operate and gives us a closer 1 to 1 relationship for Wordpress vs Joomla.

Finally I should mention that we will be making another “map” table which will give us a map of the categories again, so we can reference, the old category id and get the new category id, we will also record the section id, so we can drop all of the content into the content tables correctly.

So without further ado, her is the code.

<?php
error_reporting(E_ALL);
//
// Include The configuration file
//
include('config.php');
 
//
// Create a new connection to the Wordpress Database
//
$db = new  ezSQL_mysql($wp_db_user, $wp_db_pass, $wp_db, $wp_db_host);
echo "Initialised WP DB<br/>";
 
//
// Create a connection to the Joomla Database
//
$jb = new  ezSQL_mysql($j_db_user, $j_db_pass, $j_db, $j_db_host);
echo "Initialised JOS DB<br/>";
 
//
// Create a new table in your Joomla database to store the new 
// category and section ID's so that we can map posts and articles to them. We will destroy this table as one of the final steps
//
 
$jb->query( "CREATE TABLE `jos_wp_category_map` (`wp_cat_id` INT NOT NULL ,`jos_cat_id` INT NOT NULL ,`jos_sec_id` INT NOT NULL) ENGINE = MYISAM ");
echo "Created Category Map table<br>";
 
//
// This function iterates through the categories and children and updates the ID's
//
function updateCategory($category, $newParentID)
{
	global $db, $jb, $wp_prefix, $j_prefix;
	$children = $db->get_results("SELECT t.term_id as term_id, t.name as tname, t.slug as tslug, tt.description as description, tt.parent as parent FROM ".$wp_prefix."terms AS t INNER JOIN ".$wp_prefix."term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('category') and parent=".$category."  ORDER BY t.name");
 
	foreach($children as $child) {
		updateCategory($child->term_id, $newParentID);
		//Check if we are insterting into 1.5 or 1.0.x
		if($j_version=='1.5') {
			//Insert the latest category 
			$jb->query("insert into ".$j_prefix."categories (title, alias, section, description, published) Values('".$child->tname."', '".$child->tslug."', '".$newParentID."', '".$child->description."', 1)");
		}
		else
		{
			//Insert a matching Category for this top level category (now exists as Joomla Section and Category)
			$jb->query("insert into ".$j_prefix."categories (title, name, section, description, published) Values('".$child->tname."', '".$child->tslug."', '".$newParentID."', '".$child->description."', 1)");
 
		}
 
		// Insert into our temp storage/reference table
		$jb->query("insert into jos_wp_category_map (wp_cat_id, jos_cat_id, jos_sec_id) values(".$child->term_id.", ".$jb->insert_id.", ".$newParentID.")");
 
	}
 
}
 
//
// This query grabs all of the categories from the wp tables, wp stores categories in a taxonomy format, which essentially means that there
// is a multipurpose table which holds everything from categories, to tags, this consists of 3 tables in total, but we just want to grab information
// from 2 of them, term_taxonomy and terms. We could limit this query to grab only what we want, but I use the full query for anyone interested
// in seeing exactly what information is stored for category in Wordpress, more an FYI query than being specific and to the point, and does not harm
// since we will in 99% of cases be grabbing less than 1000 rows.
$categories = $db->get_results("SELECT t.term_id as term_id, t.name as tname, t.slug as tslug, tt.description as description, tt.parent as parent FROM ".$wp_prefix."terms AS t INNER JOIN ".$wp_prefix."term_taxonomy AS tt ON t.term_id = tt.term_id WHERE tt.taxonomy IN ('category')  and parent=0 ORDER BY t.name");
 
echo "<br/>Categories Selected from WP";
 
//
// Loop through the results array and work our magic
//
foreach($categories as $category) {
 
	//Check if we are insterting into 1.5 or 1.0.x
	if($j_version=='1.5') {
		// Insert the Parent Category into Joomla as a "Section"
		$jb->query("insert into ".$j_prefix."sections (title, alias, scope, description, published) values ('".$category->tname."', '".$category->tslug."', 'content', '".$category->description."', 1)");
		$newParentID = $jb->insert_id;
		//Insert the section as a category of itself
		$jb->query("insert into ".$j_prefix."categories (title, alias, section, description, published) Values ('".$category->tname."', '".$category->tslug."', '".$newParentID."', '".$category->description."', 1)");
	}
	else
	{
		// Insert the Parent Category into Joomla as a "Section"
		$jb->query("insert into ".$j_prefix."sections (title, name, scope, description, published) values ('".$category->tname."', '".$category->tslug."', 'content', '".$category->description."', 1)");
 
		$newParentID = $jb->insert_id;
		//Insert as a category to it's own section
		$jb->query("insert into ".$j_prefix."categories (title, name, section, description, published) Values ('".$category->tname."', '".$category->tname."', '".$newParentID."', '".$category->description."', 1)");
 
	}
 
	// Insert into our temp storage/reference table
	$jb->query("insert into jos_wp_category_map (wp_cat_id, jos_cat_id, jos_sec_id) values(".$category->term_id.", ".$jb->insert_id.", ".$newParentID.")");
 
	//Jump into the recursive function and update all of the subcategories and align them in a Joomla! style of section vs Category
	updateCategory($category->term_id, $newParentID);
 
}
 
echo "Category Import completed";
?>

The code above is not perfectly tuned but I ran out of time because work became exceedingly busy and I didn’t have the time to put in to refine the code to my usual standards. However it is functional and does the job we intended.

It inserts the category, grabs the first sub-category and inserts that, and then enters a recursive function in order to find each of the sub-categories of the first sub-category until it runs out of records to go through. This could be simplified to make the recursion hit immediately which i will do once I wrap this into a downloadable script, otherwise enjoy. The content will be following close on the heels.

I wanted to just reach out to let you know the second part of the script and tutorial on converting from Wordpress to Joomla is in the works, I am only managing about 5 minutes a day working on it but am at the stage where I am writing the major parts of the code.

Whilst it seems fairly simple to write a category importer, Joomla and Wordpress manage categories in very different ways. Wordpress also allows for an infinite level of categories, whilst Joomla restricts you to Section and dingle category hierarchy. This presents a fairly complex set of problems and it means a lot of work in order to sort out and create a new structure that still makes some sense and holds true when we move to Joomla.

On the surface it isn’t a complex problem but as the developer we have made some pretty harsh decisions on behalf of the people that will be using the script to convert their systems, it also means that we have to do some lateral thinking about how we are going to progrematically take something that may be a hierarchy of “foo >> Bar >> doe >> Ray” into something like “Foo >> Ray” or “doe >> Ray” essentially we cant make everyone happy and we are going to have to make some people happy and others unhappy. I plan on writing a switch into the converter also, that allows a site administrator to say they want it to work so that any parent, no matter it’s place in the hierarchy becomes a section as well as staying a child, this allowing for everyone brings drama of it’s own though!

Stay tuned
Dan

I didn’t want to start the site with one of those first “welcome” posts, because well they generally lack merit and offer nothing on the reading front for new and old viewers, however I find it incredibly hard to resist or really start with anything other than a welcome message.

I am still finalising design and much more about the site, and the setup is of course going to take a few days until I am happy.

But I thought I would offer you a an idea of what you are going to find on this site once we are fully alive and kicking.

The hope is that this will become an active outlet for me to provide some insights for new coders and old coders alike. I am not the worlds best PHP programmer but I have yet to be confronted with something I could not put together, even if it was not the right way.
Over the coming weeks months and maybe years I am going to start posting some blog posts about some of the bits of code that I have written across the years, and share much of this code with you for your own use and critique.

I have often written snippets of code to automate tasks and that I use in my day to day usage of the net, many of the things I write are mere hacks and changes to functionality of other code.
In my never ending search for the perfect application for my busiest site http://www.silvertails.net, I have had cause to write many a converter between the various open source software packages available on the net. As a result I have a good collection of code where some has been of value to only me, but through this site I will be releasing these chunks of code, so that you can use them, change them and mold them into something useful for you.

Finally the site is going to be an avenue for me to “Geek Out” and spare more poor fiance the boredom when I begin waxing lyrical about some crazy code idea or internet scheme I have dreamed up during the night.

So with that said, I look forward to getting under way and getting something to you and as such I extend a warm welcome to any who take the time to read and visit this site.