README

A simple dependency injection container with focus on automatic wiring (auto-wiring) dependencies.

Introduction

Simple DIC is implemented with auto-wiring at the forefront.

This basically means that if a class can be created by automatically by recursively resolving dependencies then you will get a class back, even if you haven't manually put anything into the container!

For this to happen fully 100% automatically, all class constructor argumentss will need to have explicit type hints for instantiable types (i.e. they need to be non-abstract, non-interface, non-native).

If the types required are using interfaces and/or abstract classes then you can define a type mapping with the addTypeMapping method, to tell the container what concrete classes to resolve the types to.

If the types required have dependencies on native types (e.g. the constructor requires a string), then you can define factory methods to create the instance manually. You're factory method can define arguments which will also be autowired.

I have tried to optimise this implementation as much as possible.

Example

In the example below we are able to get an instance of the Foo class, simply be asking the container for one, no setup of the container is required other than instantiating it.

class Baz {

    public __construct();
}

class Bar {

    public __construct(Baz baz);
}

class Foo {

    public __construct(Bar bar);
}

$container = new \JBuncle\SimpleDic\Container();
$fooInstance = $container->getInstance(Foo::class);

This will automatically instantiate instances of Foo, Bar and Baz, and store those instances in the container automatically. Therefore subsequently calling $container->getInstance(Bar::class) will give you the same class instance used to create Foo.

Adding Factory Functions

Factory functions allow you define a callback to use to manually create instances (lazily) when needed.

Useful for instances that cannot be created using full automatic autowiring.

Type Mapping

Type mapping allows you to tell the container what type to use when a specific type is requested.

This is useful for when you want to define what concrete or extending class to use when a supertype or interface is required.

PSR Compatibility

A simple DIC can be easily converted into a PHP FIG PSR-11 (psr/container v2) compatible implementation using the PsrAdapter wrapper class:

$containerFactory = new \JBuncle\SimpleDic\ContainerFactory();
$container = $containerFactory->create();

/* @var $psrContainer \Psr\Container\ContainerInterface */
$psrContainer = new \JBuncle\SimpleDic\PsrAdapter($container);