Thoughts: time warp to 2009


Media through the ages

The 20th century was witness to the birth of what is arguably the most popular device in the history of mankind: the television. TV is a communications technology that has revolutionised the delivery of information, entertainment and artistic expression to the masses. More recently, we have all witnessed (and participated in) the birth of the Internet, a technology whose potential makes TV pale into insignificance in comparison (although, it seems, TV isn't leaving us anytime soon). These are fast-paced and momentous times we live in. I thought now would be a good opportunity to take a journey back through the ages, and to explore the forms of (and devices for) media and communication throughout human history.


What are fossil fuels?

Let me begin with a little bit of high school revision. Fossil fuels are composed primarily of carbon and hydrogen. There are basically three types of fossil fuels on Earth: coal, oil, and natural gas. It's common knowledge that fossil fuels are the remains of prehistoric plants and animals. That's why they're called "fossil fuels" (although they're not literally made from prehistoric bones, or at least not in any significant amount). Over a period of millions of years, these organic remains decomposed, and they got buried deep beneath rock and sea beds. A combination of heat and pressure caused the organic material to chemically alter into the fuel resources that we're familiar with today. The fuels became trapped between layers of rock in the Earth's geological structure, thus preserving them and protecting them from the elements up to the present day.

Hang on. Let's stop right there. Fossil fuels are dead plants and animals. And we burn them in order to produce the energy that powers most of our modern world (86% of it, to be precise). In other words, modern human civilisation depends (almost exclusively) upon the incineration of the final remains of some of the earliest life on Earth. In case there weren't enough practical reasons for us to stop burning fossil fuels, surely that's one hell of a philosophical reason. Wouldn't you say so?


jQuery text separator plugin

For my premiere debĂșt into the world of jQuery plugin development, I've written a little plugin called text separator. As I wrote on its jQuery project page, this plugin:

Lets you separate a text field into two parts, by dragging a slider to the spot at which you want to split the text. This plugin creates a horizontal slider above a text field. The handle on that slider is as long as its corresponding text field, and its handle 'snaps' to the delimiters in that text field (which are spaces, by default). With JS disabled, your markup should degrade gracefully to two separate text fields.

This was designed for allowing users to enter their 'full name' in one input box. The user enters their full name, and then simply drags the slider in order to mark the split betwen their first and last names. While typing, the slider automatically drags itself to the first delimiter in the input box.

Want to take it for a spin? Try a demo. You'll see something like this:

Text separator screenshot

Text separator screenshot


Hook soup

Of late, I seem to keep stumbling upon Drupal hooks that I've never heard of before. For example, I was just reading a blog post about what you can't modify in a _preprocess() function, when I saw mention of hook_theme_registry_alter(). What a mouthful. I ain't seen that one 'til now. Is it just me, or are new hooks popping up every second day in Drupal land? This got me wondering: exactly how many hooks are there in Drupal core right now? And by how much has this number changed over the past few Drupal versions? Since this information is conveniently available in the function lists on, I decided to find out for myself. I counted the number of documented hook_foo() functions for Drupal core versions 4.7, 5, 6 and 7 (HEAD), and this is what I came up with (in pretty graph form):

Drupal hooks by core version

Drupal hooks by core version

And those numbers again (in plain text form):

  • Drupal 4.7: 41
  • Drupal 5: 53
  • Drupal 6: 72
  • Drupal 7: 183

Aaaagggghhhh!!! Talk about an explosion — what we've got on our hands is nothing less than hook soup. The rate of growth of Drupal hooks is out of control. And that's not counting themable functions (and templates) and template preprocessor functions, which are the other "magically called" functions whose mechanics developers need to understand. And as for hooks defined by contrib modules — even were we only counting the "big players", such as Views — well, let's not even go there; it's really too massive to contemplate.


Installing the uploadprogress PECL extension on Leopard

The uploadprogress PECL extension is a PHP add-on that allows cool AJAX uploading like never before. Version 3 of Drupal's FileField module is designed to work best with uploadprogress enabled. As such, I found myself installing a PECL extension for the first time. No doubt, many other Drupal developers will soon be finding themselves in the same boat.

Unfortunately, for those of us on Mac OS X 10.5 (Leopard), installing uploadprogress ain't all smooth sailing. The problem is that the extension must be compiled from source in order to be installed; and on Leopard machines, which all run on a 64-bit processor, it must be compiled as a 64-bit binary. However, the gods of Mac (in their infinite wisdom) decided to include with Leopard (after Xcode is installed) a C compiler that still behaves in the old-school way, and that by default does its compilation in 32-bit mode. This is a right pain in the a$$, and if you're unfamiliar with the consequences of it, you'll likely see a message like this coming up in your Apache error log when you try to install uploadprogress and restart your server:

PHP Warning:  PHP Startup: Unable to load dynamic library '/usr/local/php5/lib/php/extensions/no-debug-non-zts-20060613/' - (null) in Unknown on line 0

Hmmm… (null) in Unknown on line 0. WTF is that supposed to mean? (You ask). Well, it means that the extension was compiled for the wrong environment; and when Leopard tries to execute it, a low-level error called a segmentation fault occurs. In short, it means that your binary is $#%&ed.

But fear not, Leopard PHP developers! Read on for some instructions for how to install uploadprogress by compiling it as a 64-bit binary.


Self-referencing symlinks can hang your IDE

One of my current Drupal projects has been giving me a headache lately, due to a small but very annoying problem. My PHP development tools of choice, at the moment, are Eclipse PDT and TextMate. Both of these generally work great for me. I prefer TextMate if I have the choice (better config options + much more usable), but I switch to Eclipse whenever I need a good debugger (or a bit of contextual help / autocomplete). However, they haven't been working well for me in this case. Every time I try to load in the source code for this one particular project, the IDE either hangs indefinitely (in Eclipse), or it slows down to a crawl (in TextMate). I've been tearing my hair out, trying to work out the cause of this problem, which has forced me to edit individual files for several weeks, and which has meant that I can't have a debugger or an IDE workspace for this project. Finally, I've nailed it: self-referencing symlinks are the culprit.

The project is a Drupal multisite setup, and like most multisite setups, it uses a bunch of symlinks in order for multiple subdomains to share a single codebase. For each subdomain, I create a symlink that points to the directory in which it resides; in effect, each symlink points to itself. When Apache comes along, it treats a symlink as the "directory" for a subdomain, and it follows it. By the time Drupal is invoked, we're in the root of the Drupal codebase shared by all the subdomains. Everything works great. All our favourite friends throw a party. Champagne bottles pop.

The bash command to create the symlinks is pretty simple — for each symlink, it looks something like this:

ln -s . subdomain

Unfortunately, a symlink like this does not play well with certain IDEs that try to walk your filesystem. When they hit such a symlink, they get stuck infinitely recursing (or at least, they keep recursing for a long time before they give up). The solution? Simple: delete such symlinks from your development environment. If this is what's been dragging your system down, then removing them will instantly cure all your woes. For each symlink, deleting it is as simple as:

rm subdomain

(Don't worry, deleting a symlink doesn't also delete the thing that it's pointing at).


Deployment and migration: hot at DrupalCon DC

There was no shortage of kick-a$$ sessions at the recent DrupalCon DC. The ones that really did it for me, however, were those that dealt with the thorny topic of deployment and migration. This is something that I've been thinking about for quite a long time, and it's great to see that a lot of other Drupal people have been doing likewise.

The thorniness of the topic is not unique to Drupal. It's a tough issue for any system that stores a lot of data in a relational database. Deploying files is easy: because files can be managed by any number of modern VCSes, it's a snap to version, to compare, to merge and to deploy them. But none of this is easily available when dealing with databases. The deployment problem is similar for all of the popular open source CMSes. There are also solutions available for many systems, but they tend to vary widely in their approach and in their effectiveness. In Drupal's case, the problem is exacerbated by the fact that a range of different types of data are stored together in the database (e.g. content, users, config settings, logs). What's more, different use cases call for different strategies regarding what to stage, and what to "edit live".

Read on to find out about:

  • Context, Spaces and Exportables
  • Deploy module
  • Other solutions presented
  • How we've come a long way