class ApiRequest extends FormRequest
{
    ...
    public function locale()
    {
        $lang = $this->header('Accept-Language');
        return $lang ? $lang : 'uz';
    }
}

class SomeResource extends JsonResource
{
    public function toArray($request)
    {
        return [
            'id' => $this->id,
            ...
        ];
    }
}