(Tutorial) Basic Breadcrumbs And Taxonomy

Tutorial : Basic Breadcrumbs And Taxonomy

In this series, I show you how to patch up some of taxonomy's bugs; how to combine it with other Drupal modules to make it more effective; and also how to extend it (by writing custom code) so that it does things that it could never do before, but that it should have been able to do right from the start. In sharing all these new ideas and techniques, I hope to make life easier for those of you that use and depend on taxonomy; to give hope to those of you that have given up altogether on taxonomy; to open up new possibilities for the future of the official taxonomy module (and for the core Drupal platform); and to kindle discussion and criticism on the material that I present.

The primary audience of this series is fellow web developers that are a part of the Drupal community. In order to appreciate the ideas presented here, and to implement the examples given, it is recommended that you have at the very least used and administered a Drupal site before. Knowledge of PHP programming and of MySQL / PostgreSQL (or even other SQL) queries would be good. You do not need to be a hardcore Drupal developer to understand this series - I personally do not consider myself to be one (yet :-)) - but it would be good if you've tinkered with Drupal's code and have at least some familiarity with it, as I do. If you're not part of this audience, then by all means read on, but don't be surprised if very soon (if not already!) you have no idea what I'm talking about.

I thought part 1 was about breadcrumbs...??

And it is - you're quite right! So, now that I've got all that introductory stuff out of the way, let's get down to the guts of this post, which is - as the title suggests - basic breadcrumbs and taxonomy (for those of you that don't see any bread, be it white, multi-grain, or wholemeal, check out this definition of a breadcrumb).

Because let's face it, that's what breadcrumbs are: basic. It's one of those fundamental things that you'd expect would work 100% right out of the box: you make a new site, you post content to it, you assign the content a category, and you take it for granted that a breadcrumb will appear, showing you where that post belongs in your site's category tree. At least, I thought it was basic when I started out on this side of town. Jakob Nielson (the web's foremost expert on usability) thinks so too, as this article on deep linking shows. But apparently, Drupal thinks differently.

It's the whole many-to-many relationship business that makes things complicated in Drupal. With a CMS that supports only one-to-many relationships (that is, each piece of content has only one parent category - but the parent category can have many children), making breadcrumbs is simple: you just trace a line from a piece of content, to its parent, to it's parent's parent, and so on. But with Drupal's taxonomy, one piece of content might have 20 parents, and each of them might have another 10 each. Try tracing a line through that jungle! The fact that although you can use many-to-many relationships, you don't have to, doesn't make a difference: taxonomy was designed to support complex relationships, and if it is to do that properly, it has to sacrifice breadcrumbs. And that's the way it works in Drupal: the taxonomy system seldom displays breadcrumbs for terms, and never displays them for nodes.

Well, I have some slightly different ideas to Drupal's taxonomy developers, when it comes to breadcrumbs. Firstly, I believe that an entire site should fall under a single 'master' category hierarchy, and that breadcrumbs should be displayed on every single page of the site without fail, reflecting a page's position in this hierarchy. I also believe that this master hierarchy system can co-exist with the power and flexibility that is inherent to Drupal's taxonomy system, but that additional categories should be considered 'secondary' to the master one.

Look at the top of this page. Check out those neat breadcrumbs. That's what this entire site looks like (check for yourself if you don't believe me). By the end of this first part of the series, you will be able to make your site's breadcrumbs as good as that. You'll also have put in place the foundations for yet more cool stuff, that can be done by extending the power of taxonomy.

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Courtesy : Greenash.net.au