@Crell

• Senior Architect, Palantir.net
• Drupal Association Advisor
• Web Services & Context Initiative Owner
• Co-Author,
  Drupal 7 Module Development,
  Packt Publishing
• Architectural Gadfly
• Nerf Gunslinger

What we do

Undesirable results of that legacy..

• .. no clean separation of configuration, logic and content
  That's how you get so much flexibility
• .. no clean deployment and staging concept
  A natural result of the first point
• .. inconsistent cache layers
  Result of highly dynamic environment
• .. function callback AOP is not everyone's cup of tea
  Very simple and powerful, though, and works in PHP 4
• .. lots of legacy baggage
  That's what happens when you're 11 years old. :-)
• .. NIH (not invented here) syndrome
  As every PHP project had until ~2010

Web Services and Context Core Initiative (WSCCI)

The original plan...

The Web Services and Context Core Initiative (WSCCI) aims to transform Drupal from a first-class CMS to a first-class REST server with a first-class CMS on top of it. To do that, we must give Drupal a unified, powerful context system that will support smarter, context- sensitive, easily cacheable block-centric layouts and non-page responses using a robust unified plugin mechanism.

Huh?

Page layout in Drupal 7

Page layout in Drupal 8 (planned)

Drupal 7 page flow

"As long as we're fixing that we may as well bake REST support in."

Why Symfony?

• Just wanted a request/response library
• Symfony2 vs. Zend: Symfony2

  

• Continue implementing
• Oh, wait, you did this already...

  

Drupal 7

Not very well separated

Symfony2

Very separated

Symfony2 Applications

One approach...

Drupal 8

(That's the plan, anyway)

So what are we using?

So far...

The kernel

• We're all in
• HttpFoundation, HttpKernel, Routing, EventDispatcher
• Steer as close to existing components as possible
• Borrow some of the full-stack extensions
  • Auto-loading of controller arguments

Routing

• For now, just wrapping our old route lookup logic
• A typical Drupal site has ~1000 routes. (That's what happens when you have a powerful UI.)
• New Matcher/MatcherDumper/Generator in progress
  • Database-backed
  • Retain fit-based path matching
  • Extend with mimetype-based routing
  • Tentative work on a new stand-alone negotiation library

Dependency Injection

• Drupal has lots of global dependencies (Procedural code is like that...)
• Start by centralizing the globals...
• "Dependency Injection Container:
  The scariest name for a giant array of objects we could come up with."
• Once they're in the container, easier to refactor

Transitional state

    function drupal_container(ContainerBuilder $reset = NULL) {
      static $container = NULL;
      if (isset($reset)) {
        $container = $reset;
      }
      elseif (!isset($container)) {
        $container = new ContainerBuilder();
      }
      return $container;
    }
    

      $langcode = drupal_container()->get('language_interface')->langcode;
    

EventDispatcher

Hooks

Hooks

Benefits

• Like EventDispatcher, but uses function_exists() for registration
• Used for procedural AOP
• Faster than EventDispatcher
• No need to compile

Limitations

• No class autoloading
• Inherently global dispatcher means hard to unit test
• Only one of each hook per module

Hooks

    function mymodule_node_access($node, $op, $account) {
      if ($op == 'edit'
          && $node->uid == $account->uid
          && $node->created > (REQUEST_TIME - 3600)) {
        return NODE_ACCESS_ALLOW;
      }
      return NODE_ACCESS_IGNORE;
    }
    

        $return = module_invoke_all('node_access', $node, 'update', $account);
      

Hooks in Drupal 8

Prediction (warning, I know better than to gamble):

• Drupal 8 will have both EventDispatcher and Hooks
• EventDispatcher closer to the core, Hooks further out
• Drupal 9: Just EventDispatcher? We'll see...

Twig

Templating in Drupal 7

• PHP-as-template-language
• Powerful preprocessing/filtering system.
• Array-based rendering: Defer rendering until the last possible moment

Templating in Drupal 7

Benefits

• Extremely flexible
• No need to compile templates (easier development)
• On-ramp for front-end developers to become PHP developers
• "All template languages eventually evolve to become Turing Complete"

Drawbacks

• Extremely opaque
• That flexibility leads to unpredictability
• Front-end need to become PHP developers

DrupalCon Denver - March 2012

Twig in Drupal 8

Maybe!

Benefits

• More secure
• More front-end developer friendly
• Twig.js (Thank you, Johannes!)
• Not Drupal-proprietary

Drawbacks

• Extremely different model makes transition difficult
• Need to figure out how to secure the compiled templates

We could use a hand!

Also under consideration...

• YAML (Oh wait, that went in already)
• Composer
• ChainRouter (Symfony CMF)
• Even some non-Symfony libraries
• ... Potentially others

Google image search for "Symfony Newbie"

We need help

Contact people

	Larry "Crell" Garfield	Kernel, Routing, Web services
	Kris "EclipseGc" Vanderwater	ESI-based page layout
	Rob Loach	Dependency Injection
	Jen Lampton	Twig
	Greg "heyrocker" Dunlap	YAML, Configuration

Where to find us

• Drupal.org issue queue, look for the "symfony" tag
• #drupal-contribute IRC
• #drupal-wscci IRC (my initiative channel)
• Also look for Drupalers in #symfony-dev...

Collaboration

• Symfony2: MIT License
• Drupal: GPL License
• Code only flows one way. :-(
• Work can begin anywhere :-)

We're coming upstream

• Symfony2 "flash messages": Too simple for us
• drupal_set_message()
• Make less code in the world!
• Drupalers designed needs for improved API
• Drak (of Zikula CMS) implemented it
• It's now in Symfony 2.1.
• Drupal issue

File Streaming

• Readfile()? fpassthru()? X-Sendfile? One response class.
• Fabien says it should be in HttpFoundation. We agree.
• Drupal issue
• Symfony pull request
• Make less code in the world!

Odds and ends

• Response::prepare() chaining
• Improve FlattenException
• UTF-8 encoding weirdness in JSON (still open)
• Allow Router matching on a full Request (still open)
• Expect more...

Excited yet?

I hope so, because we are...