Symfony2 Meets Drupal 8

by Larry Garfield

@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

Drupal is awesome!

No REALLY!

Drupal is awesome!

Drupal is awesome if you are an end user!

Powerful admin interface

Drupal is awesome if you are a sales guy!

Well known brand

Drupal sucks if you are a developer!

Drupal sucks if you want a framework.

Drupal is CMS 1st, development framework 2nd

That is a natural result of Drupal's history

Drupal has evolved into a CMS/framework hybrid:
A "framlication"

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

It's all his fault
Continue implementing
Oh, wait, you did this already...

It's all his fault

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

I'd show a diagram here, but you've seen it already.

That's the whole point :-)

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

01function drupal_container(ContainerBuilder $reset = NULL) {
02  static $container = NULL;
03  if (isset($reset)) {
04    $container = $reset;
05  }
06  elseif (!isset($container)) {
07    $container = new ContainerBuilder();
08  }
09  return $container;
10}

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

Now we can inject the language as we move other things into the container.

Eventually remove the wrapper function and inject all the things!

EventDispatcher

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

1function mymodule_node_access($node, $op, $account) {
2  if ($op == 'edit'
3      && $node->uid == $account->uid
4      && $node->created > (REQUEST_TIME - 3600)) {
5    return NODE_ACCESS_ALLOW;
6  }
7  return NODE_ACCESS_IGNORE;
8}

`1`	`$return` `= module_invoke_all('node_access',` `$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

We must get rid of these Arrays of Doom.

--Karoly Negyesi

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 in UR pull requests, improvin' ur Framework

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...

Questions?

http://groups.drupal.org/wscci

Be nice to me on Joind.in!

https://joind.in/talk/view/6600

Stalk me on Twitter!

@Crell

Symfony2 Meets Drupal 8

by Larry Garfield

@Crell

What we do

Drupal is awesome!

No REALLY!

Drupal is awesome!

Drupal is awesome if you are an end user!

Powerful admin interface

Drupal is awesome if you are a sales guy!

Well known brand

Drupal sucks if you are a developer!

Drupal sucks if you want a framework.

Drupal is CMS 1st, development framework 2nd

That is a natural result of Drupal's history

Drupal has evolved into a CMS/framework hybrid:A "framlication"

Undesirable results of that legacy..

Web Services and Context Core Initiative (WSCCI)

The original plan...

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?

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

Routing

I'd show a diagram here, but you've seen it already.

That's the whole point :-)

Dependency Injection

Transitional state

EventDispatcher

Hooks

Hooks

Hooks

Hooks in Drupal 8

Twig

Templating in Drupal 7

Templating in Drupal 7

DrupalCon Denver - March 2012

--Karoly Negyesi

Twig in Drupal 8

Also under consideration...

Google image search for "Symfony Newbie"

We need help

Contact people

Where to find us

Collaboration

We're in UR pull requests, improvin' ur Framework

We're coming upstream

File Streaming

Odds and ends

Excited yet?

I hope so, because we are...

Questions?

http://groups.drupal.org/wscci

Drupal has evolved into a CMS/framework hybrid:
A "framlication"