Module Development

Building Custom Panel Panes (CTools Content Types) in Drupal 7


Content types (a.k.a. panel panes) are one of CTools' most visible, versatile, and easy to learn APIs. In this tutorial, we're going to build a custom content type (or panel pane depending on what you call it) that display's a twitter user's latest feeds. As with any new CTools content type, you need to have at minimum three files in following structure:

Intro to Drupal 6 Multistep Form Domination Using Chaos Tools

The mere words "multistep form" once gave me a feeling of dread. There are several techniques (arguably hacks) that enable multistep forms in drupal 6. However, if you've ever used them, you'll know that they are a not techniques for the faint of heart.

While Merlinofchaos's multistep form wizard is not for the faint of heart either, I will say I found programming the forms to be fun. The setup takes a bit of focus, but after that, writing the steps is almost too easy.

Chaos Tool's is distinct:

wombat wizard
  1. See that stepper and buttons in the above image? You never will need to micromanage what step your form is on using the wizard. If you set up the form, it figures that sort of stuff out for you. Since it knows about stuff like "$step", its perfectly happy to figure out whether it should display a next, back, or finish button. I like code that works for me.
  2. Every step in a form is a distinct form_id, that has its own #submit, #validate, and(god knows what else can be done with it via form api). Within the steps, you should never need to think any harder than you would writing a simple form with a message, and an email address. Proof can be found below in the actual form arrays, and the submit functions.
  3. There are thousands of ways you can mess up a multistep form -- in a sense, the wizard lets you make your biggest mistakes in one $form_info array, while keeping the majority of the code (the formapi arrays, and form processing/validation functions) in small, easy to understand units that anyone with even intermediate formapi knowledge could work with.
  4. This wizard DOES power a number of complicated multistep forms that you may use every day - the multistep forms in panels in particular. In a way, its just the most recent chapter of Earl Miles vs. Drupal's formapi -- a saga that has gone on since version 4.7. [come to think of it, i think lullabot needs to make a feature film about that epic story]

Interested? Start Here

Here's a Live Demo of the Wombat Deployment tool I wrote that uses the wizard. Only impressive in how easily it was written, and how easily i could write a 3rd, 4th, 5th, or 20 steps following the same pattern [ the subject of future posts are hinted in a rogue file in the download.]

To get started building multistep forms, follows these steps.

  1. Download Chaos Tools
  2. Advanced Help. If you start futzing with this, you'll want the docs merlinofchaos wrote on the wizard. They are available through this module only.
  3. My example module, the wombat tool to rule them all!
  4. check back in a few for all the corrections

The full code, and detailed doc on the $form_info array will only be made available to freaks who click the "read more" link.

PHP5 Reflection And You


The phpdocs put it kind of weirdly:

PHP 5 comes with a complete reflection API that adds the ability to reverse-engineer classes, interfaces, functions and methods as well as extensions.

I prefer the notorious c.h.x.'s definition

chx: it's like this insane cool weaponset of PHP which is like totally unknown :)

Reflection is a very powerful too that lets you understand the code running in your enviroment. This is particularly important for drupal development, as so much of drupal is based on functions that call functions (e.g. hooks).

The point of this tutorial is to show you how much ass reflection can kick, in so little code. The following page finds out every menu item that calls a function hidden away in a remote file, and gives you the location of the callback function: filepath, and line number and all. Note that the vast majority of code is merely used to output the test table. Obviously, this example merely scratches the surface of useful things you could do with this api.

hook_views_query_alter : alter views queries with array keys

While building a product comparison website, I ran into a situation that required a view to sort using one of 2 possible price totals depending on a users profile: lets say "red state", "blue state". The goal was to open up the product comparison tables (order, fields, field names, and filtering questions and all), as well as the underlying data to this companies' staff, so a homebrew wasn't an option (which it shouldn't be, almost 99% of the time).

Luckily, there were only two possible prices for those products, so all I had to do was create two CCK *decimal* fields [ this is important, because text, and integer fields don't properly store or sort decimal points for prices ]. Then, on hook_cron, or a node submit, I updated the two totals based on other itemized fields.

However, how would the view know which column to sort products by based on a flag stored in the users session? There's about 5 ways to do that, so I went with the 1 minute solution:

Set up two sorts in a single view, and implement hook_views_query_alter(&$view, &$query)

function product_compare_views_query_alter(&$view, &$query) {
// fyi, anonymous sessions need a record in the user table of 0 to work at all....
if ($_SESSION['pref']['state_color'] == 'red') {
// we'll have to do the less popular red query
    // which's key is [1] (weighted second in the views sort order interface)
  else {
// otherwise, don't do the hill billy logic at all....


In theory, you could write a custom algorithm that built its own sort queries based on a criteria using this method. You could also probably alter filters, or fields. However, this isn't the only way to have accomplished this -- but its the easiest for me to stomach. Never use this method when existing views features, or view arguments, or even other views hooks may be the proper hammer for this nail.

If I learned anything, its that views a complex beast; flexible like F-22 -- an amazing piece of technology that offers tremendous freedom -- but often that freedom will cause you to crash in the ground if you don't think about what you are doing carefully.

Overriding Menu Page Callbacks

Sometimes you need to override more than a theme function: the entire page needs to be overridden. Drupal 6 makes it rather easy to do this.

In the example below, we call hook_menu_alter(&$callback) to override the display of every single node page view.

Instead of returning a node page, we return "[author's username] is great... for me to poop on.".


Loading a Menu, and Theming the Links in Two Lines of Code

When creating a menu [ admin/build/menu/add ] there's a field for "Menu name". We use that value to load whatever array of menu links we want. In this example, we're using "secondary-links" which comes default on most drupal installs.

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