# di

**Repository Path**: mirrors_yiisoft/di

## Basic Information

- **Project Name**: di
- **Description**: PSR-11 compatible DI container and injector
- **Primary Language**: Unknown
- **License**: BSD-3-Clause
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-08-19
- **Last Updated**: 2026-02-14

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

<p align="center">
    <a href="https://github.com/yiisoft" target="_blank">
        <img src="https://yiisoft.github.io/docs/images/yii_logo.svg" height="100px" alt="Yii">
    </a>
    <h1 align="center">Yii Dependency Injection</h1>
    <br>
</p>

[![Latest Stable Version](https://poser.pugx.org/yiisoft/di/v)](https://packagist.org/packages/yiisoft/di)
[![Total Downloads](https://poser.pugx.org/yiisoft/di/downloads)](https://packagist.org/packages/yiisoft/di)
[![Build status](https://github.com/yiisoft/di/actions/workflows/build.yml/badge.svg)](https://github.com/yiisoft/di/actions/workflows/build.yml)
[![Code coverage](https://codecov.io/gh/yiisoft/di/graph/badge.svg?token=P8W1UTwgQt)](https://codecov.io/gh/yiisoft/di)
[![Mutation testing badge](https://img.shields.io/endpoint?style=flat&url=https%3A%2F%2Fbadge-api.stryker-mutator.io%2Fgithub.com%2Fyiisoft%2Fdi%2Fmaster)](https://dashboard.stryker-mutator.io/reports/github.com/yiisoft/di/master)
[![static analysis](https://github.com/yiisoft/di/workflows/static%20analysis/badge.svg)](https://github.com/yiisoft/di/actions?query=workflow%3A%22static+analysis%22)
[![type-coverage](https://shepherd.dev/github/yiisoft/di/coverage.svg)](https://shepherd.dev/github/yiisoft/di)

[PSR-11](https://www.php-fig.org/psr/psr-11/) compatible
[dependency injection](https://en.wikipedia.org/wiki/Dependency_injection) container that's able to instantiate
and configure classes resolving dependencies.

## Features

- [PSR-11](https://www.php-fig.org/psr/psr-11/) compatible.
- Supports property injection, constructor injection, and method injection.
- Detects circular references.
- Accepts array definitions. You can use it with mergeable configs.
- Provides optional autoload fallback for classes without explicit definition.
- Allows delegated lookup and has a composite container.
- Supports aliasing.
- Supports service providers.
- Has state resetter for long-running workers serving many requests, such as [RoadRunner](https://roadrunner.dev/)
  or [Swoole](https://www.swoole.co.uk/).
- Supports container delegates.
- Does auto-wiring.

> [!NOTE]
> The container contains only shared instances. If you need a factory, use the dedicated [yiisoft/factory](https://github.com/yiisoft/factory) package.

## Requirements

- PHP 8.1 - 8.5.
- `Multibyte String` PHP extension.

## Installation

You could install the package with composer:

```shell
composer require yiisoft/di
```

## Using the container

Usage of the DI container is simple: You first initialize it with an
array of *definitions*. The array keys are usually interface names. It will
then use these definitions to create an object whenever the application requests that type.
This happens, for example, when fetching a type directly from the container
somewhere in the application. But objects are also created implicitly if a
definition has a dependency on another definition.

Usually one uses a single container for the whole application. It's often
configured either in the entry script such as `index.php` or a configuration
file:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDefinitions($definitions);

$container = new Container($config);
```

You could store the definitions in a `.php` file that returns an array:

```php
return [
    // resolve EngineMarkOne dependencies automatically
    EngineInterface::class => EngineMarkOne::class,
    
    // full definition
    MyServiceInterface::class => [
        'class' => MyService::class,
        
        // call the constructor, pass named argument "amount"
        '__construct()' => [
            'amount' => 42,
            'db' => Reference::to(SecondaryConnection::class), // instance of another dependency
        ],
        
        // set a public property
        '$name' => 'Alex',
        
        // call a public method
        'setDiscount()' => [10],
    ],
    
    // closure for complicated cases
    AnotherServiceInterface::class => static function(ConnectionInterface $db) {
        return new AnotherService($db);
    },
    
    // factory
    MyObjectInterface::class => fn () => MyFactory::create('args'),
    
    // static call
    MyObjectInterface2::class => [MyFactory::class, 'create'],
    
    // direct instance
    MyInterface::class => new MyClass(),
];
```

You can define an object in several ways:

- In the simple case, an interface definition maps an id to a particular class.
- A full definition describes how to instantiate a class in more detail:
  - `class` has the name of the class to instantiate.
  - `__construct()` holds an array of constructor arguments.
  - The rest of the config is property values (prefixed with `$`) and method calls, postfixed with `()`. They're
     set/called in the order they appear in the array.
- Closures are useful if instantiation is tricky and can be better done in code. When using these, arguments are
   auto-wired by type. `ContainerInterface` could be used to get current container instance.
- If it's even more complicated, it's a good idea to move such a code into a
   factory and reference it as a static call.
- While it's usually not a good idea, you can also set an already
   instantiated object into the container.

See [yiisoft/definitions](https://github.com/yiisoft/definitions) for more information.

After you configure the container, you can obtain a service via `get()`:

```php
/** @var \Yiisoft\Di\Container $container */
$object = $container->get('interface_name');
```

Note, however, that it's bad practice using a container directly. It's much
better to rely on auto-wiring as provided by the Injector available from the
[yiisoft/injector](https://github.com/yiisoft/injector) package.

## Using aliases

The DI container supports aliases via the `Yiisoft\Definitions\Reference` class.
This way you can retrieve objects by a more handy name:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDefinitions([
        EngineInterface::class => EngineMarkOne::class,
        'engine_one' => EngineInterface::class,
    ]);

$container = new Container($config);
$object = $container->get('engine_one');
```

## Using class aliases for specific configuration

To define another instance of a class with specific configuration, you can
use native PHP `class_alias()`:

```php
class_alias(Yiisoft\Db\Pgsql\Connection::class, 'MyPgSql');

$config = ContainerConfig::create()                                                                                                                                                     
    ->withDefinitions([
        MyPgSql::class => [ ... ]
    ]);                                                                                                                                                                                 

$container = new Container($config);
$object = $container->get(MyPgSql::class);
```

It could be then conveniently used by type-hinting:

```php
final class MyService
{
    public function __construct(MyPgSql $myPgSql)
    {
        // ...    
    }
} 
```

## Composite containers

A composite container combines many containers in a single container. When
using this approach, you should fetch objects only from the composite
container.

```php
use Yiisoft\Di\CompositeContainer;
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$composite = new CompositeContainer();

$carConfig = ContainerConfig::create()
    ->withDefinitions([
        EngineInterface::class => EngineMarkOne::class,
        CarInterface::class => Car::class
    ]);
$carContainer = new Container($carConfig);

$bikeConfig = ContainerConfig::create()
    ->withDefinitions([
        BikeInterface::class => Bike::class
    ]);

$bikeContainer = new Container($bikeConfig);
$composite->attach($carContainer);
$composite->attach($bikeContainer);

// Returns an instance of a `Car` class.
$car = $composite->get(CarInterface::class);
// Returns an instance of a `Bike` class.
$bike = $composite->get(BikeInterface::class);
```

Note that containers attached earlier override dependencies of containers attached later.

```php
use Yiisoft\Di\CompositeContainer;
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$carConfig = ContainerConfig::create()
    ->withDefinitions([
        EngineInterface::class => EngineMarkOne::class,
        CarInterface::class => Car::class
    ]);

$carContainer = new Container($carConfig);

$composite = new CompositeContainer();
$composite->attach($carContainer);

// Returns an instance of a `Car` class.
$car = $composite->get(CarInterface::class);
// Returns an instance of a `EngineMarkOne` class.
$engine = $car->getEngine();

$engineConfig = ContainerConfig::create()
    ->withDefinitions([
        EngineInterface::class => EngineMarkTwo::class,
    ]);

$engineContainer = new Container($engineConfig);

$composite = new CompositeContainer();
$composite->attach($engineContainer);
$composite->attach($carContainer);

// Returns an instance of a `Car` class.
$car = $composite->get(CarInterface::class);
// Returns an instance of a `EngineMarkTwo` class.
$engine = $composite->get(EngineInterface::class);
```

## Using service providers

A service provider is a special class that's responsible for providing complex
services or groups of dependencies for the container and extensions of existing services.

A provider should extend from `Yiisoft\Di\ServiceProviderInterface` and must
contain a `getDefinitions()` and `getExtensions()` methods. It should only provide services for the container
and therefore should only contain code related to this task. It should *never*
implement any business logic or other functionality such as environment bootstrap or applying changes to a database.

The `getExtensions()` method allows implementing the decorator pattern by wrapping existing services
with additional functionality.

A typical service provider could look like:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ServiceProviderInterface;

class CarFactoryProvider extends ServiceProviderInterface
{
    public function getDefinitions(): array
    {
        return [
            CarFactory::class => [
                'class' => CarFactory::class,
                '$color' => 'red',
            ], 
            EngineInterface::class => SolarEngine::class,
            WheelInterface::class => [
                'class' => Wheel::class,
                '$color' => 'black',
            ],
            CarInterface::class => [
                'class' => BMW::class,
                '$model' => 'X5',
            ],
        ];    
    }
     
    public function getExtensions(): array
    {
        return [
            // Note that Garage should already be defined in a container 
            Garage::class => function(ContainerInterface $container, Garage $garage) {
                $car = $container
                    ->get(CarFactory::class)
                    ->create();
                $garage->setCar($car);
                
                return $garage;
            }
        ];
    } 
}
```

Here you created a service provider responsible for bootstrapping of a car factory with all its dependencies.

An extension is callable that returns a modified service object.
In this case you get existing `Garage` service
and put a car into the garage by calling the method `setCar()`.
Thus, before applying this provider, you had
an empty garage and with the help of the extension you fill it.

To add this service provider to a container, you can pass either its class or a
configuration array in the extra config:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withProviders([CarFactoryProvider::class]);

$container = new Container($config);
```

When you add a service provider, DI calls its `getDefinitions()` and `getExtensions()` methods
*immediately* and both services and their extensions get registered into the container.

### Using service providers for decorator pattern

Service provider extensions are a powerful feature that allows implementing the decorator pattern.
This lets you wrap existing services with additional functionality without modifying their original implementation.

Here's an example of using the decorator pattern to add logging to an existing mailer service:

```php
use Psr\Container\ContainerInterface;
use Psr\Log\LoggerInterface;
use Yiisoft\Di\ServiceProviderInterface;

interface MailerInterface 
{
    public function send(string $to, string $subject, string $body): void;
}

class Mailer implements MailerInterface 
{
    public function send(string $to, string $subject, string $body): void 
    {
        // Original mailer implementation
        // Sends email via SMTP or external service
    }
}

class LoggingMailerDecorator implements MailerInterface 
{
    public function __construct(
        private MailerInterface $mailer,
        private LoggerInterface $logger
    ) {
    }
    
    public function send(string $to, string $subject, string $body): void 
    {
        $this->logger->info("Sending email to {$to}");
        $this->mailer->send($to, $subject, $body);
        $this->logger->info("Email sent to {$to}");
    }
}

class MailerDecoratorProvider implements ServiceProviderInterface 
{
    public function getDefinitions(): array 
    {
        return [];
    }
    
    public function getExtensions(): array 
    {
        return [
            MailerInterface::class => static function (ContainerInterface $container, MailerInterface $mailer) {
                // Wrap the original mailer with logging decorator
                return new LoggingMailerDecorator($mailer, $container->get(LoggerInterface::class));
            }
        ];
    }
}
```

In this example, the extension receives the original `MailerInterface` instance and wraps it with
`LoggingMailerDecorator`, which adds logging before and after sending emails. The decorator pattern
allows you to add cross-cutting concerns like logging, caching, or monitoring without changing the
original service implementation.

## Container tags

You can tag services in the following way:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDefinitions([  
        BlueCarService::class => [
            'class' => BlueCarService::class,
            'tags' => ['car'], 
        ],
        RedCarService::class => [
            'definition' => fn () => new RedCarService(),
            'tags' => ['car'],
        ],
    ]);

$container = new Container($config);
```

Another way to tag services is setting tags via container constructor:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDefinitions([  
        BlueCarService::class => [
            'class' => BlueCarService::class,
        ],
        RedCarService::class => fn () => new RedCarService(),
    ])
    ->withTags([
        // "car" tag has references to both blue and red cars
        'car' => [BlueCarService::class, RedCarService::class]
    ]);

$container = new Container($config);
```

### Getting tagged services

You can get tagged services from the container in the following way:

```php
$container->get(\Yiisoft\Di\Reference\TagReference::id('car'));
```

The result is an array that has two instances: `BlueCarService` and `RedCarService`.

### Using tagged services in configuration

Use `TagReference` to get tagged services in configuration:

```php
[
    Garage::class => [
        '__construct()' => [
            \Yiisoft\Di\Reference\TagReference::to('car'),
        ],    
    ],
],
```

## Resetting services state

Despite stateful services isn't a great practice, these are often inevitable. When you build long-running
applications with tools like [Swoole](https://www.swoole.co.uk/) or [RoadRunner](https://roadrunner.dev/) you should
reset the state of such services every request. For this purpose you can use `StateResetter` with resetters callbacks:

```php
$resetter = new StateResetter($container);
$resetter->setResetters([
    MyServiceInterface::class => function () {
        $this->reset(); // a method of MyServiceInterface
    },
]);
```

The callback has access to the private and protected properties of the service instance,
so you can set the initial state of the service efficiently without creating a new instance.

You should trigger the reset itself after each request-response cycle. For RoadRunner, it would look like the following:

```php
while ($request = $psr7->acceptRequest()) {
    $response = $application->handle($request);
    $psr7->respond($response);
    $application->afterEmit($response);
    $container
        ->get(\Yiisoft\Di\StateResetter::class)
        ->reset();
    gc_collect_cycles();
}
```

### Setting resetters in definitions

You define the reset state for each service by providing "reset" callback in the following way:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDefinitions([
        EngineInterface::class => EngineMarkOne::class,
        EngineMarkOne::class => [
            'class' => EngineMarkOne::class,
            'setNumber()' => [42],
            'reset' => function () {
                $this->number = 42;
            },
        ],
    ]);

$container = new Container($config);
```

Note: resetters from definitions work only if you don't set `StateResetter` in definition or service providers.

### Configuring `StateResetter` manually

To manually add resetters or in case you use Yii DI composite container with a third party container that doesn't support state reset natively, you could configure state resetter separately. The following example is PHP-DI:

```php
MyServiceInterface::class => function () {
    // ...
},
StateResetter::class => function (ContainerInterface $container) {
    $resetter = new StateResetter($container);
    $resetter->setResetters([
        MyServiceInterface::class => function () {
            $this->reset(); // a method of MyServiceInterface
        },
    ]);
    return $resetter;
}
```

## Specifying metadata for non-array definitions

To specify some metadata, such as in cases of "resetting services state" or "container tags," for non-array
definitions, you could use the following syntax:

```php
LogTarget::class => [
    'definition' => static function (LoggerInterface $logger) use ($params) {
        $target = ...
        return $target;
    },
    'reset' => function () use ($params) {
        ...
    },
],
```

Now you've explicitly moved the definition itself to "definition" key.

## Delegates

Each delegate is a callable returning a container instance that's used in case DI
can't find a service in a primary container:

```php
function (ContainerInterface $container): ContainerInterface
{

}
```

To configure delegates use extra config:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withDelegates([
        function (ContainerInterface $container): ContainerInterface {
            // ...
        }
    ]);


$container = new Container($config);
```

## Tuning for production

By default, the container validates definitions right when they're set. In the production environment, it makes sense to
turn it off:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withValidate(false);

$container = new Container($config);
```

## Strict mode

Container may work in a strict mode, that's when you should define everything in the container explicitly.
To turn it on, use the following code:

```php
use Yiisoft\Di\Container;
use Yiisoft\Di\ContainerConfig;

$config = ContainerConfig::create()
    ->withStrictMode(true);

$container = new Container($config);
```

## Documentation

- [Internals](docs/internals.md)

If you need help or have a question, the [Yii Forum](https://forum.yiiframework.com/c/yii-3-0/63) is a good place for that.
You may also check out other [Yii Community Resources](https://www.yiiframework.com/community).

## License

The Yii Dependency Injection is free software. It is released under the terms of the BSD License.
Please see [`LICENSE`](./LICENSE.md) for more information.

Maintained by [Yii Software](https://www.yiiframework.com/).

## Support the project

[![Open Collective](https://img.shields.io/badge/Open%20Collective-sponsor-7eadf1?logo=open%20collective&logoColor=7eadf1&labelColor=555555)](https://opencollective.com/yiisoft)

## Follow updates

[![Official website](https://img.shields.io/badge/Powered_by-Yii_Framework-green.svg?style=flat)](https://www.yiiframework.com/)
[![Twitter](https://img.shields.io/badge/twitter-follow-1DA1F2?logo=twitter&logoColor=1DA1F2&labelColor=555555?style=flat)](https://twitter.com/yiiframework)
[![Telegram](https://img.shields.io/badge/telegram-join-1DA1F2?style=flat&logo=telegram)](https://t.me/yii3en)
[![Facebook](https://img.shields.io/badge/facebook-join-1DA1F2?style=flat&logo=facebook&logoColor=ffffff)](https://www.facebook.com/groups/yiitalk)
[![Slack](https://img.shields.io/badge/slack-join-1DA1F2?style=flat&logo=slack)](https://yiiframework.com/go/slack)