Inside the Symfony DIC and Config

Symfony DIC and Configuration

Andreas Hucks @meandmymonkey Senior Developer, Trainer, Consultant SensioLabs Deutschland

The Project:

http://goo.gl/rS06X

Life without Dependency Injection

class Logger { public function log($message, $level =
'INFO') { $formatter = new XmlFormatter(); $log = $formatter-‐>format( $message, $level ); $this-‐>writeLog($log); } }

Problems?

class Logger { function __construct(FormatterInterface $formatter) {
$this-‐>formatter = $formatter; } [...] }

class Logger { [...] public function
log($message, $level = 'INFO') { $log = $this-‐>formatter-‐>format( $message, $level ); $this-‐>writeLog($log); } }

Alternative: Setter Injection

class Logger { [...] function setFormatter(FormatterInterface
$formatter) { $this-‐>formatter = $formatter; } [...] }

“Dependency Injection is where components are given their dependencies through
their constructors, methods, or directly into fields.”

Interfacing with the Webservice

interface ExchangeRatesInterface { /**
* @return array */ public function getRates(); /** * @param string $currency * @return float */ public function getRate($currency); }

interface AdapterInterface { /**
* @return string */ public function getRawData(); }

interface ParserInterface { /**
* @param string $rawData * @return array */ public function parse($rawData); }

Task Implement class ExchangeRates using MockAdapter and XmlParser. Generate output
using ExchangeRatesCommand .

The Service Container

The Service Container is simply a PHP object that manages
the instantiation of services.

$container-‐>get('logger'); $container-‐>getParameter('logger.class');

Vocabulary Elements

service An object managed by the Dependency Injection Container.

argument A parameter given by the DIC to a service,
via the constructor or a mutator method (setter).

parameter A configuration value.

<service id="sensio.logger" class="Sensio\Logger" > <!-‐-‐
Constructor arguments -‐-‐> <argument>/path/to/app/logs/app.log</argument> <argument type="service" id="sensio.logger.xml_formatter" /> <!-‐-‐ Methods to call -‐-‐> <call method="setDefaultSeverity"> <argument>DEBUG</argument> </call> <!-‐-‐ Tags -‐-‐> <tag name="tools.logger" /> </service>

Vocabulary Attributes

id The service identifier or name

class The service class to instantiate

alias An alias name for this service

public Set to false to make the service private and
used internally

Vocabulary Service Elements

argument An argument to pass to a method (constructor or
setter)

call A method to call on the newly created object

tag A tag to attach to the service definition

Vocabulary Argument Attributes

type Define the nature of the argument. Allowed values: string,
constant, collection or service

id The service name, if the argument is a service

key The argument key when dealing with the collection type

http://goo.gl/FNJ9H

Task Write a container configuration!

Configuration

public function load( array $configs, ContainerBuilder
$container ) { $configuration = new Configuration(); $config = $this -‐>processConfiguration($configuration, $configs); $loader = new Loader\XmlFileLoader( $container, new FileLocator(__DIR__.'/../Resources/config') ); $loader-‐>load('exchangerates.xml'); }

Array ( [0] => Array (
[exchange_rates] => Array ( [curl] => Array ( [CURLOPT_TIMEOUT] => 5 ) ) ) [1] => Array ( [exchange_rates] => Array ( [curl] => Array ( [CURLOPT_TIMEOUT] => 10, [CURLOPT_PROXY] => http:// localhost:8888 ) ) ) )

Array ( [exchange_rates] => Array (
[curl] => Array ( [CURLOPT_TIMEOUT] => 10 [CURLOPT_PROXY] => http://localhost:8888 ) [endpoint] => http://www.ecb.europa.eu/stats... ) )

class Configuration implements ConfigurationInterface { public function getConfigTreeBuilder()
{ $treeBuilder = new TreeBuilder(); $rootNode = $treeBuilder>root('acme_dic_workshop'); $rootNode -‐>children() -‐>scalarNode('some_config_var') -‐>isRequired() -‐>defaultValue('foo') -‐>end() -‐>end(); return $treeBuilder; } }

-‐>scalarNode(‘some_url') -‐>isRequired() -‐>cannotBeEmpty() -‐>validate() -‐>ifTrue(function($value)
{ return !filter_var($value, \FILTER_VALIDATE_URL); }) -‐>thenInvalid('Not a valid url.') -‐>end() -‐>end()

http://goo.gl/8sa6Q

Thanks! https://joind.in/7778

Inside the Symfony DIC and Config

Inside the Symfony DIC and Config

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