Getting started

LiteWire DI is a tiny single-file autowiring container for PHP applications, libraries, WordPress plugins, and themes. It has no runtime dependencies and does not implement Psr\Container\ContainerInterface or require psr/container.

Requirements

LiteWire DI supports PHP 7.4 and PHP 8.0–8.5.

Installation

Install it with Composer:

composer require doiftrue/litewire-di

Alternatively, copy Container.php into your project.

Use your own namespace

When copying the file, change its Kama\LiteWireDI namespace to one owned by your project so it cannot conflict with another copied version.

Resolve your first service

use Kama\LiteWireDI\Container;

final class Logger {
	public function log( string $message ): void {
		error_log( $message );
	}
}

final class ReportService {
	public function __construct(
		private readonly Logger $logger,
	) {}

	public function generate(): void {
		$this->logger->log( 'Report generated.' );
	}
}

$container = new Container();
$container->get( ReportService::class )->generate();

Neither class is registered. get() reflects ReportService, sees its Logger dependency, creates it, and stores the completed ReportService as a shared instance.

Features

• Keep the whole container in a single PHP file.
• Use no external dependencies.
• Register existing objects, classes, closure factories, and configured constructor parameters with set().
• Autowire registered and unregistered classes.
• Return shared service instances with get().
• Create a new instance every time with make().
• Pass named runtime parameters to make().
• Check whether classes and interfaces can be resolved with has().
• Use an object-first design with class and interface names as service IDs.
• Use default values for scalar constructor parameters.
• Use the modern Reflection API on PHP 8.
• Inject the container itself as a dependency.
• Cache Reflection data inside each container instance.
• Detect circular dependencies and show the full resolution chain.

Tradeoffs

• Configuration goes through parameters attached to concrete class definitions, factories, runtime parameters, or config objects. There is no standalone scalar storage.
• Invokable objects can be wrapped in closures, but are not factories automatically.
• Configuration is normal PHP code. There are no attributes or DSL (domain-specific language).

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Next step

Continue with using the container to learn when to use each public method.