README

A lightweight dependency injection container for PHP with automatic constructor resolution.

Supported PHP Versions

This library requires PHP 8.1 or higher.

Build Status

Features

• Instance-based API — fully testable, multiple containers can coexist
• Static facade (ContainerFacade) for quick usage without DI
• Auto-resolution of constructor dependencies via reflection
• Singleton support — resolve once, return same instance on subsequent calls
• Callable factories for complex construction logic
• Nullable parameter handling — resolves to null if dependency is unbound
• Default value support — uses parameter defaults for unresolvable scalar types
• Zero dependencies — requires only PHP 8.1+

Installation

composer require webfiori/container

Usage

Basic Binding

use WebFiori\Container\Container;

$container = new Container();

// Bind interface to implementation
$container->bind(LoggerInterface::class, FileLogger::class);

$logger = $container->make(LoggerInterface::class);
// Returns a new FileLogger instance

Singletons

$container->singleton(DatabaseConnection::class, MySQLConnection::class);

$a = $container->make(DatabaseConnection::class);
$b = $container->make(DatabaseConnection::class);
// $a === $b (same instance)

Auto-Resolution

The container automatically resolves constructor dependencies:

class UserRepository {
    public function __construct(DatabaseConnection $db) {
        // ...
    }
}

class UserService {
    public function __construct(UserRepository $repo, LoggerInterface $logger) {
        // ...
    }
}

$container->singleton(DatabaseConnection::class, MySQLConnection::class);
$container->bind(LoggerInterface::class, FileLogger::class);

// Automatically resolves UserRepository and LoggerInterface
$service = $container->make(UserService::class);

Callable Factories

$container->bind(CacheInterface::class, function (Container $c) {
    $config = $c->make(Config::class);
    return new RedisCache($config->get('redis.host'), $config->get('redis.port'));
});

Registering Existing Instances

$config = new Config('/path/to/config.json');
$container->instance(Config::class, $config);

Static Facade

use WebFiori\Container\ContainerFacade;

ContainerFacade::singleton(LoggerInterface::class, FileLogger::class);
$logger = ContainerFacade::make(LoggerInterface::class);

API

Container

ContainerFacade

Static wrapper around a default Container instance. Same methods as Container plus:

Behavior

• Auto-resolution: If a class is not explicitly bound, the container attempts to instantiate it by resolving its constructor dependencies recursively.
• Nullable parameters: If a dependency cannot be resolved and the parameter is nullable, null is used.
• Default values: Scalar parameters with default values use those defaults when not resolvable.
• Exceptions: ContainerException is thrown when a dependency cannot be resolved (non-existent class, abstract class, unresolvable parameter).

License

MIT