tsufeki/hmcontainer

Hierarchical dependency injection container inspired by Angular

0.3.4 2018-11-01 22:47 UTC

README

HMContainer is a dependency injection container for PHP.

Installation

With Composer:

$ composer require tsufeki/hmcontainer

Usage

Create a container:

use Tsufeki\HmContainer\Container;

$c = new Container();

Add a value (constant parameter):

$c->setValue("key", 42);

Retrieve it (HMContainer implements PSR-11):

$c->has("key"); // true
$c->get("key"); // 42
$c->get("non-existent-key"); // throws NotFoundException
$c->getOrDefault("non-existent-key", 5); // 5

Container is frozen during first get() or freeze() call and no new items can be added afterwards.

Definition objects

There are to ways to add items to the container: convenience methods Container::setValue(), ::setClass() etc. or through creating Definition objects yourself and calling Container::set(). I.e. those two lines are equivalent:

use Tsufeki\HmContainer\Definition\Value;

$c->setValue("key", 42);
$c->set("key", new Value(42));

Multi-valued keys

Add multiple items to be retrieved as an array:

$c->setValue("primes", 2, true);
$c->setValue("primes", 3, true);
$c->setValue("primes", 5, true);
$c->isMulti("primes"); // true
$c->get("primes"); // [2, 3, 5]

Class instantiation and autowiring

Add a class which will be instantiated once, during first get():

$c->setClass("aobject", AClass::class, false, ["dep1", "dep2"]);
$c->get("aobject"); // returns new AClass($c->get("dep1"), $c->get("dep2"))
$c->get("aobject"); // returns the same instance as above

Dependencies can be automatically deduced (autowired) if you use class names as DI keys:

class BClass { }

class CClass {
  public function __construct(BClass $b) { }
}

$c->setClass(BClass::class);
$c->setClass(CClass::class);
$c->get(CClass::class); // correctly contructed CClass object

Autowiring key is guessed from parameter type hint, @param tag type or special @Inject tag:

class DClass {
  /**
   * @param CClass $c
   * @param $d @Inject("dkey")
   */
  public function __construct(BClass $b, $c, $d) { }
}

Multi items are supported as well:

class Aggregator {
  /**
   * @param SomeInterface[] $impls
   */
  public function __construct(array $impls) { }
}

$c->setClass(SomeInterface::class, ConcreteImplementation1::class, true);
$c->setClass(SomeInterface::class, ConcreteImplementation2::class, true);
$c->setClass(Aggregator::class);
$c->get(Aggregator::class);

Mark parameter with @Optional to have null injected when dependency can't be found:

class Maybe {
  /**
   * @param $dep @Optional
   */
  public function __construct(Dep $dep = null) { }
}

Mix manual dependencies and autowiring by putting some nulls in dependency array:

$c->setClass(DClass::class, null, false, [null, "dep2"]);

Using Definitions as dependencies is also supported:

use Tsufeki\HmContainer\Definition\Reference;

$c->setClass(DClass::class, null, false, [null, new Reference("dep2")]);

Aliases

Add an alias to other key:

$c->setAlias("alias", "target");
$c->get("alias"); // same as $c->get("target")

Lazy items

Add a lazy item, it will return parameterless callable:

$c->setLazy('lazy', new Value(42));
$c->get('lazy'); // a callable $f such that $f() === 42

Custom definitions

You can add your custom instantiators by implementing Definition interface and using set() method:

$myFactory = new MyFactory();
$c->set("mykey", $myFactory);

Serialization

Container can be serialized and unserialized for caching with standard PHP serialize() and unserialize(), but only if you use serializable factories.

License

MIT - see LICENCE.