The state of DI in PHP


About me

Stephan Hochdörfer, bitExpert AG

Department Manager Research Labs

enjoying PHP since 1999

7 years of DI experience (in PHP)

[email protected]

@shochdoerfer

What`s this talk about?




No framework bashing! Hopefully :)



It`s all about how DI is implemented.

What`s DI about?



Inversion of control


„Hollywood principle“

What`s DI about?


new TalkService(new TalkRepository());

What`s DI about?

Consumer


What`s DI about?

Consumer Dependencies


What`s DI about?

Consumer Dependencies Container


A little bit of history...


1988


„Designing Reusable Classes“Ralph E. Johnson & Brian Foote

1996


„The Dependency Inversion Principle“Robert C. Martin

2002


2003


Spring Framework 0.9 released

2004


„Inversion of Control Containers and the Dependency Injection pattern“

Martin Fowler

2004


Spring Framework 1.0 released

2004


PHP 5.0 released

2005 / 2006


Garden, a lightweight DI container for PHP.

2006


First PHP5 framework with DI support

2007


International PHP Conference 2007 features 2 talks about DI.

2009


PHP 5.3.0 released

2010


Fabien Potencier talks about „Dependency Injection in

PHP 5.2 and 5.3“

2011


Symfony2, Flow3, Zend Framework 2 (beta)

2012


And now?


DI has finally arrived in the PHP world!


Let`s have a look at the different implementations!

Zend\Di – First steps


<?phpnamespace Acme;

class TalkService {public function __construct() {}

public function getTalks() {}

}

Zend\Di – First steps


<?php

$di = new \Zend\Di\Di();

$service = $di->get('Acme\TalkService');$service->getTalks();

Zend\Di – Constructor Injection



interface GenericRepository {public function readTalks();

}

class TalkRepository implements GenericRepository {public function readTalks() {}

}

class TalkService {public function __construct(TalkRepository $repo) {}


}

Zend\Di – Constructor Injection


<?php



Zend\Di – Setter Injection



class Logger {public function doLog($logMsg) {}

}

class TalkService {public function __construct(TalkRepository $repo) {}

public function setLogger(Logger $logger) {}


}

Zend\Di – Setter Injection


<?php$di = new \Zend\Di\Di();$di->configure(

new Zend\Di\Configuration(array(

'definition' => array('class' => array(

'Acme\TalkService' => array('setLogger' => array('required' => true)

))

))

));

$service = $di->get('Acme\TalkService');var_dump($service);

Zend\Di – Interface Injection



class Logger {public function doLog($logMsg) {}

}

interface LoggerAware {public function setLogger(Logger $logger);

}

class TalkService implements LoggerAware {public function __construct(TalkRepository $repo) {}

public function setLogger(Logger $logger) {}


}

Zend\Di – Interface Injection


<?php



Zend\Di – General usage


<?php



$service2 = $di->get('Acme\TalkService');var_dump($service2); // same instance as $service

$service3 = $di->get('Acme\TalkService',array(

'repo' => new \phpbnl12\TalkRepository())

);var_dump($service3); // new instance

Zend\Di – Builder Definition


<?php// describe dependency$dep = new \Zend\Di\Definition\Builder\PhpClass();$dep->setName('Acme\TalkRepository');

// describe class$class = new \Zend\Di\Definition\Builder\PhpClass();$class->setName('Acme\TalkService');

// add injection method$im = new \Zend\Di\Definition\Builder\InjectionMethod();$im->setName('__construct');$im->addParameter('repo', 'Acme\TalkRepository');$class->addInjectionMethod($im);

// configure builder$builder = new \Zend\Di\Definition\BuilderDefinition();$builder->addClass($dep);$builder->addClass($class);

Zend\Di – Builder Definition


<?php

// add to Di$defList = new \Zend\Di\DefinitionList($builder);$di = new \Zend\Di\Di($defList);


Symfony2


<?phpnamespace Acme\TalkBundle\Controller;use Symfony\Bundle\FrameworkBundle\Controller\Controller;use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;use Sensio\Bundle\FrameworkExtraBundle\Configuration\Template;

class TalkController extends Controller { /** * @Route("/", name="_talk") * @Template() */ public function indexAction() { $service = $this->get('acme.talk.service'); return array(); }}

Symfony2 – Configuration file


<?xml version="1.0" ?><container xmlns="http://symfony.com/schema/dic/services" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://symfony.com/schema/dic/serviceshttp://symfony.com/schema/dic/services/services-1.0.xsd">

</container>

File services.xml in src/Acme/DemoBundle/Resources/config

Symfony2 – Constructor Injection


<?xml version="1.0" ?><container xmlns="http://symfony.com/schema/dic/services"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"xsi:schemaLocation="http://symfony.com/schema/dic/services

http://symfony.com/schema/dic/services/services-1.0.xsd">

<services><service id="acme.talk.repo"

class="Acme\TalkBundle\Service\TalkRepository" />

<service id="acme.talk.service" class="Acme\TalkBundle\Service\TalkService">

<argument type="service" id="acme.talk.repo" /></service>

</services></container>

Symfony2 – Setter Injection





<services><service id="acme.talk.logger"

class="Acme\TalkBundle\Service\Logger" />

<service id="acme.talk.repo" class="Acme\TalkBundle\Service\TalkRepository" />


<argument type="service" id="acme.talk.repo" /><call method="setLogger">

<argument type="service" id="acme.talk.logger" /></call>

</service></services>

</container>

Symfony2 – Setter Injection (optional)






class="Acme\TalkBundle\Service\Logger" />




<argument type="service" id="acme.talk.logger" on-invalid="ignore" />

</call></service>


Symfony2 – Property Injection








<property name="talkRepository" type="service" id="acme.talk.repo" />


</container>

Symfony2 – private/public Services






class="Acme\TalkBundle\Service\Logger" public="false" />




<argument type="service" id="acme.talk.logger" /></call>


</container>

Symfony2 – Service inheritance





<services><service id="acme.talk.serviceparent"

class="Acme\TalkBundle\Service\TalkService" abstract="true"><property name="talkRepository" type="service"

id="acme.talk.repo" /></service>

<service id="acme.talk.service" parent="acme.talk.serviceparent" />

<service id="acme.talk.service2" parent="acme.talk.serviceparent" /></services>

</container>

Symfony2 – Service scoping







<service id="acme.talk.service"class="Acme\TalkBundle\Service\TalkService" scope="prototype"><property name="talkRepository" type="service"

id="acme.talk.repo" /></service>


Flow3 – Constructor Injection


<?phpnamespace Acme\Demo\Controller;

use TYPO3\FLOW3\Annotations as FLOW3;

/** * @FLOW3\Scope("session") */class StandardController extends \TYPO3\FLOW3\MVC\Controller\ActionController {

/** * @var \Acme\Demo\Service\TalkServiceInterface */protected $talkService;

public function __construct(\Acme\Demo\Service\TalkService $talkService) {$this->talkService = $talkService;

}

public function indexAction() {}

}

Flow3 – Constructor Injection (manually)






public function __construct(\Acme\Demo\Service\TalkService $talkService) {$this->talkService = $talkService;

}


}

Flow3 – Setter Injection (manually)






public function setTalkService(\Acme\Demo\Service\TalkService $talkService) {$this->talkService = $talkService;

}


}

Flow3 – Setter Injection (manually)


File Objects.yaml in Packages/Application/Acme.Demo/Configuration# @package AcmeAcme\Demo\Controller\StandardController: properties: talkService: object: Acme\Demo\Service\TalkService

Flow3 – Setter Injection (Automagic)






public function injectTalkService(\Acme\Demo\Service\TalkService $talkService) {$this->talkService = $talkService;

}


}

Flow3 – Setter Injection (Automagic)






public function injectSomethingElse(\Acme\Demo\Service\TalkService $talkService) {$this->talkService = $talkService;

}


}

Flow3 – Property Injection





/** * @var \Acme\Demo\Service\TalkService * @FLOW3\Inject */protected $talkService;


}

Flow3 – Property Injection (with Interface)





/** * @var \Acme\Demo\Service\TalkServiceInterface * @FLOW3\Inject */protected $talkService;


}

Flow3 – Property Injection (with Interface)


# @package AcmeAcme\Demo\Service\TalkServiceInterface: className: 'Acme\Demo\Service\TalkService'

File Objects.yaml in Packages/Application/Acme.Demo/Configuration

Flow3 – Scoping





/** * @var \Acme\Demo\Service\TalkServiceInterface * @FLOW3\Inject */protected $talkService;


}

The future?


The future (or what`s missing)?



PSR for DI container missing!


IDE support is missing...

Thank you!

http://joind.in/4768

The state of DI in PHP - phpbnl12

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