16-php-di-5-1-released.md

layout	title	author	date
blogpost	PHP-DI 5.1 released	Matthieu Napoli	September 8th 2015

I am happy to announce that PHP-DI version 5.1 has been released. This new version comes with:

• many performances improvements - some benchmarks show up to 35% performance improvements, real results will vary of course
• Zend Framework 2 integration
• factory resolution by the container
• many documentation improvements
• several bugfixes

Factory resolution

Note: examples below use the PHP 5.6 shortcut factory() instead of DI\factory().

You can define a service using a factory, the simplest example would be using a closure:

return [
    'db' => factory(function ($container) {
        return ...;
    }),
];

It can be sometimes useful to put such code in its own class, for example:

class DbFactory
{
    public function create($container)
    {
        return ...;
    }
}

You could configure this like so:

return [
    'db' => factory([new DbFactory(), 'create']),
];

But it comes with its problems:

• the DbFactory object is created for every request, even if not used
• you can't pass dependencies to the factory (you only get the $container parameter)

From v5.1 and up you can now ask PHP-DI to create the factory object on-demand (with the benefits of using dependency injection there too):

return [
    'db' => factory(['DbFactory', 'create']),
    // or with PHP 5.5
    'db' => factory([DbFactory::class, 'create']),
];

// You can use dependency injection in the factory now:
class DbFactory
{
    private $dependency;

    public function __construct(Foo $dependency)
    {
        $this->dependency = $dependency;
    }

    public function create()
    {
        return ...;
    }
}

As you can see above, it uses the notation of a PHP callable except the first array item is a class name (or any container entry) instead of the actual instance: ['DbFactory', 'create'].

To give you an idea, factory(['DbFactory', 'create']) is equivalent to the following code:

$factory = $container->get('DbFactory');
$factory->create();

(technically the $container is passed in create() but you probably don't need it)

Two things to note:

• if DbFactory::create() is a static method then the object will not be created: DbFactory::create() will be called statically (as you would expect)
• you can set any container entry name in the array, e.g. factory(['foo_bar_baz', 'create']), allowing you to configure foo_bar_baz and its dependencies like any other object

Change log

If you want the complete list of changes in this new version, head over to the change log.

Let's finish on a "Thank you" to all contributors involved in this release!