PHP Conference Japan 2022 LT 資料

phpcon2022-lt.php

<?php

/**
 * @copyright 2022 Masaru Yamagishi
 * @license CC-BY-4.0
 * @link https://fortee.jp/phpcon-2022/proposal/51f66d0e-5bae-4902-bb63-89700407204a
 * @link https://docs.google.com/presentation/d/11NCgOhSF3ZB1Kea8VD4TW9qghQjxSZwm4-IOIP2x-aQ/edit#slide=id.p
 */

declare(strict_types=1);

// [{"id":1,"name":"PHP","level":1,"jobType":1}]

// ↓

class Job
{
  public function __construct(
    public readonly int $id,
    public readonly string $name,
    public readonly int $level,
    public readonly JobType $jobType,
  ) {
  }
}

// ---

interface MappingInterface
{
    /**
     * @template T of object
     * @param string $className
     * @psalm-param class-string<T> $className
     * @param int $id
     * @return object
     * @psalm-return T
     */
    public function instantiate(string $className, int $id): object;
}

$job = $mapping->instantiate(Job::class, 1);
assert($job instanceof Job);

// ---
       
class JsonMapping implements MappingInterface
{
    /** {@inheritDoc} */
    public function instantiate(string $className, int $id): object
    {
        $records = $this->load($className);
        $record = $this->filter($records, $id);
        return $this->map($className, $record);
    }

    /**
     * json ファイルから二次元配列でデータ読み込み
     * @param string $className
     * @return array
     */
    private function load(string $className): array { /* ... */ }

    /**
     * 指定した ID のデータを取得
     * @param array $records
     * @param int $id
     * @return array
     */
    private function filter(array $records, int $id): array { /* ... */ }

    /**
     * array のデータをクラスに変換
     * @template T of object
     * @param string $className
     * @psalm-param class-string<T> $className
     * @param array $record
     * @return object
     * @psalm-return T
     */
    private function map(string $className, array $record): object
    {
        $refClass = new \ReflectionClass($className);
        $results = [];
        foreach ($refClass->getConstructor()->getParameters() as $param) {
           $name = $param->getName();
           $type = $param->getType();
           $rawValue = $record[$name];

           if ($type->allowsNull() && is_null($rawValue)) {
               $results[$name] = null;
               continue;
           }

           $results[$name] = $this->mapValue($type->getName(), $rawValue);
        }
        return $refClass->newInstanceArgs($results);
    }

    /**
     * 型名から値を変換
     * @param string $typeName
     * @param mixed $rawValue
     * @return mixed
     */
    private function mapValue(string $typeName, mixed $rawValue): mixed
    {
        return match ($typeName) {
            'int' => \is_int($rawValue) ? \intval($rawValue) : throw new \LogicException(),
            'string' => \is_string($rawValue) ? \strval($rawValue) : throw new \LogicException(),
            'float' => \is_float($rawValue) ? \floatval($rawValue) : throw new \LogicException(),
            'bool' => \is_bool($rawValue) ? \boolval($rawValue) : throw new \LogicException(),
            // ...
            default => match (true) {
                \is_subclass_of($typeName, \BackedEnum::class, true) => $typeName::from($rawValue),
                // ...
            },
        };
    }
}