mrclay/props-dic

Props is a simple DI container that allows retrieving values via custom property and method names

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github.com/mrclay/Props

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3.0.0 2019-11-26 17:56 UTC

This package is auto-updated.

Last update: 2021-09-05 18:30:19 UTC


README

Most Dependency Injection containers have fetch operations, like $di->get('foo') or $di['foo'], which don't allow your IDE to know the type of value received, nor offer you any help remembering/typing key names.

With Props, you access values via custom property reads $di->foo or method calls $di->new_foo(). This allows you to subclass the container and provide @property and/or @method PHPDoc declarations, giving your IDE and static analysis tools valuable runtime type information.

An example will help:

/**
 * @property-read Foo $foo
 * @method        Foo new_foo()
 */
class MyContainer extends \Props\Container {
    public function __construct() {
        $this->foo = function (MyContainer $c) {
            return new Foo();
        };
    }
}

$c = new MyContainer();

$foo1 = $c->foo; // your IDE knows this is a Foo instance

$foo2 = $c->new_foo(); // A fresh Foo instance

$foo3 = $c->foo; // same as $foo1

Here's a more complex example:

/**
 * @property-read string $style
 * @property-read Dough  $dough
 * @property-read Cheese $cheese
 * @property-read Pizza  $pizza
 * @method        Slice  new_slice()
 */
class PizzaServices extends \Props\Container {
    public function __construct() {
        $this->style = 'deluxe';

        $this->dough = function (PizzaServices $c) {
            return new Dough();
        };

        $this->setFactory('cheese', 'CheeseFactory::getCheese');

        $this->pizza = function (PizzaServices $c) {
            $pizza = new Pizza($c->style, $c->cheese);
            $pizza->setDough($c->dough);
            return $pizza;
        };

        $this->slice = function (PizzaServices $c) {
            return $c->pizza->getSlice();
        };
    }
}

$c = new PizzaServices;

$c->pizza; // This first resolves and caches the cheese and dough.

$c->pizza; // The same pizza instance as above (no factories called).

Since "slice" has a factory function set, we can call new_slice() to get fresh instances from it:

$c->new_slice(); // a new Slice instance
$c->new_slice(); // a new Slice instance

Your IDE sees the container as a plain old class of typed properties, allowing it to offer suggestions of available properties, autocomplete their names, and autocomplete the objects returned. It gives you much more power when providing static analysis and automated refactoring.

Compatibility

Props\Container implements ContainerInterface.

Overview

You can specify dependencies via direct setting:

$c->aaa = new AAA();

You can specify factories by setting a Closure, or by using the setFactory() method. These are functionally equivalent:

$c->bbb = function ($c) {
    return BBB::factory($c);
};

$c->setFactory('bbb', 'BBB::factory');

Resolved dependencies are cached, returning the same instance:

$c->bbb === $c->bbb; // true

Using factories

If you don't want a cached value, use new_PROPERTYNAME() to always fetch a fresh instance:

$c->new_bbb() === $c->new_bbb(); // false

Regular value sets do not store a factory, so you may want to check hasFactory() before you use new_PROPERTYNAME():

// store a value
$c->ccc = new CCC();
$c->hasFactory('ccc'); // false

// store a factory
$c->ccc = function () {
    return new CCC();
};
$c->hasFactory('ccc'); // true

You can also get access to a set factory:

$callable = $c->getFactory('ccc');

Extending a factory

Use extend to have the return value of a factory filtered before it's returned:

$c->foo = function ($c) {
    return new Foo($c->bar);
};

$c->extend('foo', function ($value, Container $c) {
    return array($value, $c->bing);
});

$c->foo; // [Foo, "bing"]

$c->new_foo(); // re-call original foo factory and re-extend output (`bar` and `bing` will be re-read)

Pimple with property access

If you're used to the Pimple API, try Props\Pimple, which just adds property access. With that you can add @property declarations and get the same typing benefits.

You can see an example that's similar to the Pimple docs.

Requirements

  • PHP 5.3

License (MIT)

See LICENSE.