Parameter Resolver

🇷🇺 Русская версия

A powerful and flexible parameter resolution library for PHP that automatically resolves function and method parameters from various sources including arrays, DI containers, and configuration.

Features

• Multiple Resolution Strategies: Resolve parameters by name, position, type, or attributes
• DI Container Integration: Seamless integration with PSR-11 containers
• Attribute Support: Native PHP 8+ attributes (#[Config], #[Inject])
• Union Types: Full support for PHP 8 union types
• Extensible Architecture: Easy to add custom resolvers
• Zero Dependencies: Core functionality requires no external dependencies
• High Performance: Optimized resolver chain with early termination

Installation

composer require bermudaphp/di-resolver

Quick Start

use Bermuda\ParameterResolver\ParameterResolver;
use Bermuda\ParameterResolver\ArrayResolver;
use Bermuda\ParameterResolver\DefaultValueResolver;

// Create resolver with basic resolvers
$resolver = new ParameterResolver([
    new ArrayResolver(),           // Resolve from provided array
    new DefaultValueResolver()     // Use default values
]);

// Define a function
function greetUser(string $name, string $greeting = 'Hello', ?int $age = null) {
    return "$greeting, $name" . ($age ? " (age: $age)" : "");
}

// Resolve parameters
$reflection = new ReflectionFunction('greetUser');
$parameters = $reflection->getParameters();

$resolvedParams = $resolver->resolve($parameters, [
    'name' => 'John',
    'age' => 25
]);

// Result: ['John', 'Hello', 25]
echo greetUser(...$resolvedParams); // "Hello, John (age: 25)"

Core Resolvers

ArrayResolver

Resolves parameters by name or position from provided array:

$resolver = new ArrayResolver();

// By name
$params = ['username' => 'john', 'email' => 'john@example.com'];

// By position  
$params = [0 => 'john', 1 => 'john@example.com'];

ArrayTypedResolver

Resolves parameters by object type scanning:

$resolver = new ArrayTypedResolver();

$params = [
    'userService' => new UserService(),
    'logger' => new Logger()
];

function processUser(UserService $service, Logger $logger) {
    // Parameters resolved automatically by type
}

ContainerResolver

Resolves from PSR-11 DI containers with attribute support:

use Bermuda\DI\Attribute\Config;
use Bermuda\DI\Attribute\Inject;

$resolver = new ContainerResolver($container);

function createUser(
    #[Config('database.host')] string $dbHost,
    #[Inject('user.repository')] UserRepository $repo,
    UserService $service  // Resolved by type from container
) {
    // All parameters resolved automatically
}

DefaultValueResolver

Uses parameter default values:

function processData(array $data, bool $validate = true, ?string $format = null) {
    // $validate will be true, $format will be null if not provided
}

NullableResolver

Resolves nullable parameters to null:

function optionalService(?LoggerInterface $logger = null) {
    // $logger will be null if not resolvable
}

DI Container Integration

Full Integration Example

use Bermuda\ParameterResolver\ParameterResolver;

// Create resolver with all standard resolvers
$resolver = ParameterResolver::createDefaults($container);

class UserController
{
    public function createUser(
        #[Config('app.name')] string $appName,
        #[Inject('user.validator')] UserValidator $validator,
        UserRepository $repository,           // From container by type
        array $userData,                      // From provided parameters
        bool $sendEmail = true,               // Default value
        ?LoggerInterface $logger = null       // Nullable fallback
    ) {
        // All parameters resolved automatically
        $user = new User($userData);
        
        if ($validator->validate($user)) {
            $repository->save($user);
            
            if ($sendEmail && $logger) {
                $logger->info("User created in $appName");
            }
        }
        
        return $user;
    }
}

// Usage
$method = new ReflectionMethod(UserController::class, 'createUser');
$resolvedParams = $resolver->resolve(
    $method->getParameters(),
    ['userData' => $_POST, 'sendEmail' => false]
);

$controller = new UserController();
$user = $controller->createUser(...$resolvedParams);

Configuration Management

The Config attribute supports dot notation and various data sources:

use Bermuda\DI\Attribute\Config;

// Simple config access
function connectDatabase(#[Config('database.host')] string $host) {}

// With default values
function getApiKey(#[Config('api.key', 'default-key')] string $key) {}

// Disable dot notation
function getLiteralKey(#[Config('app.debug', explodeDots: false)] bool $debug) {}

// Deep nesting
function getNestedValue(
    #[Config('services.external.api.endpoints.users')] string $endpoint
) {}

ArrayAccess Support

$config = new ArrayObject([
    'database' => ['host' => 'localhost', 'port' => 3306]
]);

$container->set('config', $config);

function connect(#[Config('database.host')] string $host) {
    // Works with ArrayAccess objects
}

Advanced Usage

Custom Resolvers

class EnvironmentResolver implements ParameterResolverInterface
{
    public function resolve(
        ReflectionParameter $parameter,
        array $providedParameters = [],
        array $resolvedParameters = []
    ): ?array {
        $envVar = 'APP_' . strtoupper($parameter->getName());
        $value = $_ENV[$envVar] ?? null;
        
        return $value !== null ? [$parameter->getPosition(), $value] : null;
    }
}

// Add to resolver chain
$resolver = new ParameterResolver([
    new EnvironmentResolver(),
    new ArrayResolver(),
    new DefaultValueResolver()
]);

Union Type Support

function flexibleHandler(string|UserService $handler, int|float $value) {
    // Resolves first matching type from union
}

$params = [
    'UserService' => new UserService(),  // Matches UserService from union
    'value' => 42                        // Matches int from union
];

Resolver Priorities

$resolver = new ParameterResolver([
    new ArrayResolver(),           // Priority 1: Explicit parameters
    new ArrayTypedResolver(),      // Priority 2: Type matching
    new ContainerResolver($container), // Priority 3: DI container
    new DefaultValueResolver(),    // Priority 4: Default values
    new NullableResolver()         // Priority 5: Nullable fallback
]);

Error Handling

use Bermuda\ParameterResolver\ParameterResolutionException;

try {
    $resolvedParams = $resolver->resolve($parameters, $providedParams);
} catch (ParameterResolutionException $e) {
    echo "Failed to resolve parameter: " . $e->parameter->getName();
    echo "Provided parameters: " . print_r($e->providedParameters, true);
    echo "Already resolved: " . print_r($e->resolvedParameters, true);
}

Performance Tips

1. Order resolvers by frequency - put most commonly used resolvers first
2. Use typed parameters when possible for faster ArrayTypedResolver matching
3. Avoid deep nesting in Config paths for better performance
4. Cache reflection objects when resolving the same signatures repeatedly

Requirements

• PHP 8.4 or higher

License

MIT License. See LICENSE for details.