DI Container

The DependencyInjection component allows you to standardize and centralize the way objects are constructed in your application.

Remember the Car Class From Studygroup 06

We can update it to set the make and the number of passengers it can accomodate

class Car implements Vehicle {
    // . . . 
    public function __construct($make, $size = 5) {
        $this->make = $make;
        $this->size = $size;
    }
    // . . . 
    public function getMake() {
        return $this->make;
    }

    public function getSize() {
        return $this->size;
    }

    public function getPerson($name, $type = Person::PASSENGER) {
        return $this->personList[$type][$name];
    }
}

Use the DI Container

To create a new Car

use Symfony\Component\DependencyInjection\ContainerBuilder;

$container = new ContainerBuilder();
$container->register('car', '\SDPHP\StudyGroup07\Car')
    ->addArgument('Toyota')
    ->addArgument(12);



$car = $container->get('car');


echo $car->getMake() . ' Size: ' . $car->getSize();

Use the DI Container

To create a more flexible vehicles using Parameters (config values)

use Symfony\Component\DependencyInjection\ContainerBuilder;

$container = new ContainerBuilder();
$container->setParameter('car.make', 'Mazda');
$container->setParameter('car.size', 2);


$container->register('car', '\SDPHP\StudyGroup07\Car')
    ->addArgument('%car.make%')
    ->addArgument('%car.size%');

$car = $container->get('car');

echo $car->getMake() . ' Size: ' . $car->getSize();

Use the DI Container

Let's make sure every car has a driver

use Symfony\Component\DependencyInjection\Reference;
use SDPHP\StudyGroup07\Person;

// . . .
$container->register('person_driver.class', '\SDPHP\StudyGroup07\Person')
    ->addArgument('Juan')
    ->addArgument(Person::DRIVER);

$container->register('car', '\SDPHP\StudyGroup07\Car')
    ->addArgument('%car.make%')
    ->addArgument('%car.size%')
    ->addMethodCall(
        'addPerson', 
        [new Reference('person_driver.class')]);
$car = $container->get('car');
echo $car->getMake() . ' Size: ' . $car->getSize() . '. ';
echo 'The Driver name is: ' . $car->getPerson('Juan', Person::DRIVER)->getName();

Setting up the COntainer with Configuration Files

Use the DI Container

To create set other values. Let's make sure every car has a driver

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;
use SDPHP\StudyGroup07\Person;

$container = new ContainerBuilder();
$loader = new YamlFileLoader($container, new FileLocator(__DIR__));
$loader->load('/vagrant/studygroup/app/config/services.yml');

$car = $container->get('car');

echo $car->getMake() . ' Size: ' . $car->getSize() . PHP_EOL;
echo 'The Driver name is: ' . $car->getPerson('Joe', Person::DRIVER)->getName();

services.yml

parameters:
    car.make: Ford
    car.size: 4
services:
    person_driver.class:
        class: \SDPHP\StudyGroup07\Person
        arguments: ["Joe", "driver"]
    car:
        class: \SDPHP\StudyGroup07\Car
        arguments: ["%car.make%", "%car.size%"]
        calls:
            - [addPerson, ["@person_driver.class"] ]