Want to be a Drupal 8 Expert? Start with Symfony

I'm not a Drupal developer, but I do know a lot about Drupal 8. I know how the event system works, what a service is, how it relates to a dependency injection container and how the deepest and darkest of Drupal's request-response workflow looks.

How?

Because I'm a Symfony developer. And if you want to get a jumpstart on Drupal 8, you should be to. I'm not saying use Symfony instead of Drupal - they each solve very different problems.

Use both.

What you can Learn from Symfony

How about a list?

1) Code

Simply put: Drupal 8 and Symfony share a lot of code, called components (think, little PHP libraries). You can see these right inside the Drupal core on GitHub and Symfony documents these individually (Symfony Components). If you use Symfony right now, you're using a lot of code from Drupal 8.

2) Double your Weaponry

Symfony isn't always the right tool for a job, and neither is Drupal. But when you learn Symfony, you're doubling the arsenal that you can throw at any problem.

And because so much is shared, you get these 2 tools at a discounted learning price. Value!

3) PHP Namespaces

Drupal 8 uses PHP namespaces. But great news! These aren't that hard, and after using Symfony for a bit (or any modern PHP framework or library), this learning curve will be a thing of the past.

Bonus: if you have 2 minutes, we have a screencast for you: PHP Namespaces in 120 Seconds.

4) Object-Oriented-ness

Yay, objects! Interfaces! Flexibility!

Objects are everywhere in Symfony and Drupal (and again, in almost every PHP library these days). Use Symfony for a day to get way ahead on this.

5) The Container

If you're a geek, one of the most exciting things about Drupal 8 is its use of a "dependency injection container". Quick, take 20 minutes and learn about dependency injection and containers: Dependency Injection and the art of services and containers. I'll wait.

In Symfony, everything stops and starts with the container. And in Drupal 8, things will be much the same. The container (and good use of object-oriented principles) allows you to modify any part of the Drupal core without - as Larry Garfield puts it - killing any kittens (see D8FTW: Hacking Core Without Killing Kittens).

Get into Symfony and you'll get right into the container. We even intro it early in our Symfony series (Rendering a Template) cause it's just so darn important.

6) HttpKernel

HttpKernel: the beating heart of Symfony2 and Drupal 8.

It's a Symfony component (little PHP library!) and I'd tell you what it does, but then I'd have to kill you, or at least dive you into a bunch of deep code over coffee.

But basically: it's the code that starts with request information and transforms it into a response. It involves dispatching Symfony events (another concept!), executing a controller and returning a Response. Geek out here: The HttpKernel Component.

So the code-sharing between Symfony and Drupal 8 doesn't include frivolous pieces: they share the most fundamental code that makes things go. No matter how different 2 different cars are, under the hood, they move using the same basic mechanics. (Bad pun:) So take Symfony for a drive.

Start using Symfony!

If you want to step through a real project, do yourself a favor and go through our Symfony2 series and then build something. I've listed the 4 episodes, with highlights that directly affect Drupalers:

• Symfony2 Ep1 (install, bundles, routing, controller, services, Composer)
• Symfony2 Ep2 (a lot more controllers)
• Symfony2 Ep3 (JSON, dependency injection container, services, DI tags)
• Symfony2 Ep4 (Assetic, Deployment)

And for an even lower barrier to entry, try Silex! Here's a Silex app::

require_once __DIR__.'/../vendor/autoload.php';

$app = new Silex\Application();

$app->get('/drupal/{version}', function($version) {
    return 'You\'re using Drupal '.$version;
});

$app->run();

And this still uses all the most important components used in Drupal 8 - HttpKernel, EventDispatcher and a dependency injection container.

So start kicking butt in Drupal 8 right now and add another tool to your arsenal.

Happy Drupal-Symfonying!