README

PHP Dependency Injection Container

Installation

composer require mts7/php-dependency-injection

Usage

Set

Getting an instantiated object can only happen after the container knows about the class. One way to tell the container about the definition is to use the set method. set can take an alias or fully-qualified class name as the first parameter and a fully-qualified class name, instantiated object, or null as the second parameter.

Full Example

$container = new Container();

// set an alias with a reference to the class name
$container->set('car', Car::class);
$car = $container->get('car');

// set the name to the class name and provide an instantiated object
$container->set(Car::class, new Car());
$car = $container->get(Car::class);

// provide only the name of the class and get an instantiated object
$container->set(Car::class);
$car = $container->get(Car::class);

Load

To make things easier for projects, passing the abstract and concrete values to Container can happen through the load method. Provide an array indexed by the abstract ID (key, class name, etc.) with a value of a concretion.

Load handles a variety of parameters, allowing for most implementations to work out-of-the-box. When both the key and value are present, the list of definitions available adds valid values and their keys. When the config array has no key, load uses the value to determine the key (which should be the fully-qualified class name). Each value goes through validation to determine if the concretion provided is a valid class or object. Check the tests for examples.

Load is best used when combined with a factory that provides auto-loading of a preconfigured list of abstractions and their concretions.

Full Example

// the factory would create a new Container, then call ->load($config) with the appropriate values
$container = ContainerFactory::create();

$car = $container->get(Car::class);
$car->setName('Taco');
echo $car->getName();

Get

When a class has its own dependencies, all dependencies can exist once they are set in the container. The container uses auto-wiring through Reflection to determine which parameters are classes and then instantiate each one.

Full Example

$container = new Container();
$container->load([Color::class, Car::class]);

// there is no need to pass `Color` to the container since all dependencies load automatically
$car = $container->get(Car::class, ['Alice']);
// getting the color comes from Car's dependency rather than an outside influence
$car->getColor()->setHex('#F0F8FF');
echo $car->getName() . ' is ' . $car->getColor()->getHex();