Why is Yii2 using arrays for rules instead of objects?

Question

Rules in Yii2 models look like this:

[
    // checks if "level" is 1, 2 or 3
    ['level', 'in', 'range' => [1, 2, 3]],
]

Wouldn't it be better if they were objects like this?

[
  new RangeRule('level', [1, 2, 3])
]

Answer 1

You can use validator objects like this:

use yii\validators\Validator;
use yii\validators\NumberValidator;
use yii\validators\StringValidator;

class TestModel extends \yii\base\Model
{
    public $firstProperty;
    public $secondProperty;

    public function rules()
    {
        return [
            new NumberValidator(['attributes' => ['firstProperty'], 'integerOnly' => true, 'min' => 0, 'max' => 100]),
            new StringValidator(['attributes' => ['secondProperty'], 'max' => 5]),
        ];
    }
}

Moreover, you can decorate these objects as you want (using additional classes and methods):

class TestModel extends \yii\base\Model
{
    public $firstProperty;
    public $secondProperty;

    public function rules()
    {
        // Prepare Int validator
        $validatorInt              = new NumberValidator();
        $validatorInt->integerOnly = true;
        $validatorInt->min         = 0;
        $validatorInt->max         = 100;

        // Prepare String validator
        $validatorString      = new StringValidator();
        $validatorString->max = 5;

        // Make rules
        return [
            static::_makeRule(['firstProperty'], $validatorInt),
            static::_makeRule(['secondProperty'], $validatorString),
        ];
    }

    protected function _makeRule($attrName, Validator $validatorObj)
    {
        $validatorObj = clone $validatorObj;

        $validatorObj->attributes = (array)$attrName;

        $validatorObj->init();                          // Initializes validator and normalizes values

        return $validatorObj;
    }

}