README

A minimal, zero-dependency PSR-11 container implementation for PHP.

All services are resolved lazily on first access and reused on subsequent calls.

Requirements

• PHP >= 8.4
• psr/container ^2.0

Installation

composer require karolak/psr-container

Usage

use Karolak\PsrContainer\Container;

$container = new Container([
    LoggerInterface::class => static fn (): FileLogger => new FileLogger('/var/log/app.log'),
    Connection::class      => static fn (): Connection => new Connection('sqlite::memory:'),
    UserRepository::class  => static function (Container $c): UserRepository {
        return new UserRepository(
            $c->get(Connection::class),
            $c->get(LoggerInterface::class),
        );
    },
]);

$repository = $container->get(UserRepository::class);

Each factory receives the container instance as its only argument, so you can resolve other services as dependencies. Every factory is called at most once — subsequent calls to get() return the cached instance.

OPcache optimization

For best performance, define your container factories in a dedicated PHP file. This allows OPcache to compile and cache the file, avoiding repeated parsing on every request.

// config/services.php
return [
    LoggerInterface::class => static fn (): FileLogger => new FileLogger('/var/log/app.log'),
    Connection::class      => static fn (): Connection => new Connection('sqlite::memory:'),
];

// public/index.php
$container = new Container(require __DIR__ . '/../config/services.php');

License

MIT