Let's Do The Time Warp Agai-i-i-i-n!! (Please, $DEITY, no...)

For those who may somehow not be aware of it, LinkedIn is a (generally quite good) professionally-oriented social-networking site. This is not Facebook, fortunately. It's not geared towards teenagers raving about the latest corporate boy band du jour. It often can be, however, a great place to network with people from a variety of vocational, industry and/or functional backgrounds to get in contact with people, share information, and so on.

One of the essential features of LinkedIn is its groups, which are primarily used for discussions and job postings. In the venerable Usenet tradition, these discussions can have varying levels of insightful back-and-forth, or they can degenerate into a high-fidelity emulation of the "Animal House" food fight. As with Usenet, they can often give the appearance of doing both at the same time. Unlike Usenet, one has to be a member of LinkedIn to participate.

One of the (several) groups I follow is LinkedPHPers, which bills itself as "The Largest PHP Group" on LinkedIn. Discussions generally fall into at least one of a very few categories:

• How do I write code to solve "this" problem? (the 'professional' version of "Help me do my homework");

• What do people know/think about "this" practice or concept?

• I'm looking for work, or people to do work; does anybody have any leads?

As veterans of this sort of discussion would expect, the second type of discussion can lead to long and passionate exchanges with varying levels of useful content (what became known on Usenet as a "flame war.") The likelihood of such devolution seems to be inversely proportional to its specificity and proportionally to the degree which the concept in question is disregarded/unfamiliar/unknown to those with an arguable grasp of their Craft.

It should thus be no surprise that a discussion on the LinkedPHPers group of "Procedural vs Object Oriented PHP Programming" would start a flame war for both of the above reasons. With 58 responses over the past month as I write this, there are informational gems of crystal clarity buried in the thick, gruesome muck of proud ignorance. As Abraham Lincoln is reported to have said, "Better to remain silent and be thought a fool than to speak out and remove all doubt."

What's my beef here? Simply that this discussion thread is re-fighting a war that was fought and settled over a quarter-century ago by programming in general. The reality is that any language that has a reasonable implementation of OOP (with encapsulation/access control, polymorphism and inheritance, in that order by my reckoning) should be used in that way.

Several of the posts trot out the old canard about a performance 'penalty' when using OOP. In practice, that's true of only the sharpest edge cases – simple, tiny, standalone classes that should never have been developed that way because they don't provide a useful abstraction of a concept within the solution space, generally by developers who are not professionally knowledgeable of the concepts involved and quite often by those copying and pasting code they don't understand into their own projects (which they also don't understand). That bunch sharply limited the potential evolution and adoption of C++ in the '80s and '90s, and many of their ideological brethren have made their home in Web development using PHP.

Yes, I know that "real" OOP in PHP is a set of tacked-on features, late to the party; first seriously attempted in PHP 4, with successively evolving implementations in 5.0, 5.2 and 5.3, with the semi-mythological future PHP 6 adding many new features. I know that some language features are horribly unwieldy (which is why I won't use PHP namespaces in my own code; proven idea, poor implementation). But taken as a whole, it's increasingly hard to take the Other Side ("we don' need no steeeenkin' objects") at all seriously.

The main argument for ignoring the "ignore OOP" crowd is simply this: competent, thoughtful design using OOP gives you the ability to know and prove that your code works as expected, and data is accessed or modified only in the places and ways that are intended. OOP makes "software-as-building-blocks" practical, a term that first gained currency with the Simula language in the mid-1960s. OOP enables modern software proto-engineering practices such as iterative development, continuous integration and other "best practices" that have been proven in the field to increase quality and decrease risk, cost and complexity.

The 'ignore OOP in PHP' crowd like to point to popular software that was done in a non-OOP style, such as Drupal, a popular open-source Web CMS. But Drupal is a very mature project, by PHP standards; the open-source project seems to have originated in mid-2000, and it was apparently derived from code written for a project earlier still. So the Drupal code significantly predates PHP 5, if not PHP 4 (remember, the first real whack at OOP in PHP). Perusing the Drupal sources reveals an architecture initially developed by some highly experienced structured-programming developers (a precursor discipline to OOP); their code essentially builds a series of objects by convention, not depending on support in the underlying language. It is a wonder as it stands – but I would bet heavily that the original development team, if tasked with re-implementing a Web CMS in PHP from a blank screen, would use modern OO principles and the underlying language features which support them.

And why would such "underlying language features" exist and evolve, especially in an open-source project like PHP, if there was not a real, demonstrable need for them? Saying you're not going to do OOP when using PHP is metaphorically akin to saying you intend to win a Formula One race without using any gear higher than second in the race.

Good luck with that. You might want to take a good, hard look at what your (more successful) colleagues are doing, adopt what works, and help innovate your Craft further. If you don't, you'll continue to be a drag on progress, a dilettante intent upon somehow using a buggy whip to accelerate your car.

It doesn't work that way anymore.

Tutorials, best practices and staying current

A gent by the name of Brian Carey has written a very nice little tutorial on "Creating an Atom feed in PHP", and gotten it published on the IBM DeveloperWorks site. In the space of about ten pages, Brian gives a stratospheric overview of what Atom is and why PHP is a good language for developing Atom-aware apps, and then gets into the tutorial - defining a MySQL database table to hold the data used to 'feed' the Atom feed, and writing code to get the data out and put it into the form that a reader such as NetNewsWire expects an Atom feed to be in.

Now, to be fair, Brian describes himself as "an information systems consultant who specializes in the architecture, design, and implementation of Java enterprise applications", and the paper is clearly meant as a whirlwind tutorial, not to be taken by the careful/experienced reader as necessarily production-quality code. And if this had been published in, say, 2002 or so, I'd have thought it a great how-to for banging out some PHP 4 code. But this is 2009 PHP 4 is a historical artifact, and blogs and industry journals of seemingly every stripe are decrying the poor quality (security, maintainability, etc.) of PHP code... much of which is still written as if it were the turn of the century, ignoring PHP 5's numerous new features and the best practices that both spawned them and grew from them.

So what's really wrong with doing things like they did in Ye Olden Tymes™?

• Procedural code makes it harder to make changes (fix bugs, add features, change to reflect new business rules) and be certain that those changes don't introduce new defects. This is largely because...
• While it is possible to test procedural code using automatable tools like PHPUnit, it's a lot harder and more complex than testing a clean, object-oriented design.
• Hard-coding everything, interspersing 'magic values' throughout code, is a major hindrance to future reuse - or present debugging;
• Using quick-and-dirty, old-style database APIs exposes you to the risk of input data that is more 'dirty' than it should be - opening the door to SQL injection and other nastiness;
• Not staying current exposes your code to the risk that it's either using features that have since been deprecated or removed entirely, or (arguably worse), the risk that new features (such as standard library additions) make some of your existing code redundant at best.

Each of these, to varying degrees, is true of much of the PHP code I've read in the last couple of years, including that in the DeveloperWorks paper. For example, the DW paper's code makes use of the old-style PHP4 mysql_* API rather than the more abstract/portable MDB2 database abstraction layer. And there's also the rather terse implementation of a date3339() function for converting a timestamp to RFC 3339 output format, that's now nicely handled through the standard PHP DateTime class.

How would I have done things instead? Read the next few posts in this blog to find out. And, of course, comments are always welcome.