The state of DI in PHP - phpbnl12

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)
 S.Hochdoerfer@bitExpert.de
 @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


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!


ZendDi – First steps
<?php
namespace Acme;

class TalkService {
public function __construct() {
}

public function getTalks() {
}
}


ZendDi – First steps
<?php

$di = new ZendDiDi();

$service = $di->get('AcmeTalkService');
$service->getTalks();


ZendDi – Constructor Injection
<?php
namespace Acme;

interface GenericRepository {
public function readTalks();
}

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

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

}
}


ZendDi – Constructor Injection
<?php




ZendDi – Setter Injection
<?php
namespace Acme;

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

class TalkService {
}

public function setLogger(Logger $logger) {
}

}
}


ZendDi – Setter Injection
<?php
$di->configure(
new ZendDiConfiguration(
array(
'definition' => array(
'class' => array(
'AcmeTalkService' => array(
'setLogger' => array('required' => true)
)
)
)
)
)
);

var_dump($service);


ZendDi – Interface Injection
<?php
namespace Acme;

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

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

class TalkService implements LoggerAware {
}

public function setLogger(Logger $logger) {
}

}
}


ZendDi – Interface Injection
<?php




ZendDi – General usage
<?php


var_dump($service);

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

$service3 = $di->get(
'AcmeTalkService',
array(
'repo' => new phpbnl12TalkRepository()
)
);
var_dump($service3); // new instance


ZendDi – Builder Definition
<?php
// describe dependency
$dep = new ZendDiDefinitionBuilderPhpClass();
$dep->setName('AcmeTalkRepository');

// describe class
$class = new ZendDiDefinitionBuilderPhpClass();
$class->setName('AcmeTalkService');

// add injection method
$im = new ZendDiDefinitionBuilderInjectionMethod();
$im->setName('__construct');
$im->addParameter('repo', 'AcmeTalkRepository');
$class->addInjectionMethod($im);

// configure builder
$builder = new ZendDiDefinitionBuilderDefinition();
$builder->addClass($dep);
$builder->addClass($class);


ZendDi – Builder Definition
<?php

// add to Di
$defList = new ZendDiDefinitionList($builder);
$di = new ZendDiDi($defList);

var_dump($service);


Symfony2
<?php
namespace AcmeTalkBundleController;
use SymfonyBundleFrameworkBundleControllerController;
use SensioBundleFrameworkExtraBundleConfigurationRoute;
use SensioBundleFrameworkExtraBundleConfigurationTemplate;

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


Symfony2 – Configuration file
File services.xml in src/Acme/DemoBundle/Resources/config
<?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">

</container>


Symfony2 – Constructor Injection

<services>
<service id="acme.talk.repo"
class="AcmeTalkBundleServiceTalkRepository" />

<service id="acme.talk.service"
class="AcmeTalkBundleServiceTalkService">
<argument type="service" id="acme.talk.repo" />
</service>
</services>
</container>


Symfony2 – Setter Injection

<services>
<service id="acme.talk.logger"
class="AcmeTalkBundleServiceLogger" />


<call method="setLogger">
<argument type="service" id="acme.talk.logger" />
</call>
</service>
</services>
</container>


Symfony2 – Setter Injection (optional)

<services>
class="AcmeTalkBundleServiceLogger" />


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


Symfony2 – Property Injection

<services>

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


Symfony2 – private/public Services

<services>
class="AcmeTalkBundleServiceLogger" public="false" />


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


Symfony2 – Service inheritance

<services>
<service id="acme.talk.serviceparent"
class="AcmeTalkBundleServiceTalkService" abstract="true">
</service>

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

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


Symfony2 – Service scoping

<services>

class="AcmeTalkBundleServiceTalkService" scope="prototype">
</service>
</services>
</container>


Flow3 – Constructor Injection
<?php
namespace AcmeDemoController;

use TYPO3FLOW3Annotations as FLOW3;

/**
* @FLOW3Scope("session")
*/
class StandardController extends TYPO3FLOW3MVCControllerActionController {
/**
* @var AcmeDemoServiceTalkServiceInterface
*/
protected $talkService;

public function __construct(
AcmeDemoServiceTalkService $talkService) {
$this->talkService = $talkService;
}

}
}


Flow3 – Constructor Injection (manually)
<?php


/**
*/
/**
*/

public function __construct(
}

}
}


Flow3 – Setter Injection (manually)
<?php


/**
*/
/**
*/

public function setTalkService(
}

}
}


Flow3 – Setter Injection (manually)
File Objects.yaml in Packages/Application/Acme.Demo/Configuration
# @package Acme
AcmeDemoControllerStandardController:
properties:
talkService:
object: AcmeDemoServiceTalkService


Flow3 – Setter Injection (Automagic)
<?php


/**
*/
/**
*/

public function injectTalkService(
}

}
}


Flow3 – Setter Injection (Automagic)
<?php


/**
*/
/**
*/

public function injectSomethingElse(
}

}
}


Flow3 – Property Injection
<?php


/**
*/
/**
* @var AcmeDemoServiceTalkService
* @FLOW3Inject
*/

}
}


Flow3 – Property Injection (with Interface)
<?php


/**
*/
/**
* @FLOW3Inject
*/

}
}


Flow3 – Property Injection (with Interface)
File Objects.yaml in Packages/Application/Acme.Demo/Configuration
# @package Acme
AcmeDemoServiceTalkServiceInterface:
className: 'AcmeDemoServiceTalkService'


Flow3 – Scoping
<?php


/**
*/
/**
* @FLOW3Inject
*/

}
}


The future?


The future (or what`s missing)?


PSR for DI container missing!


IDE support is missing...

http://joind.in/4768

The state of DI in PHP - phpbnl12

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