Yii 2 CompareValidator的一点思考

Yii 2 CompareValidator的一点思考

起因是YiiChina社区里的一个问题：

为什么用compareAttribute验证两个密码是否一致时,我两个密码输入是个数不同的0时,验证通过了? 
array('pwd2', 'compare', 'compareAttribute' => 'password', 'message' => '两次密码必须一致'),

看了下CompareValidator的实现，发现针对字符串的比较处理上，确实有待商榷的地方。

/**
 * Compares two values with the specified operator.
 * @param string $operator the comparison operator
 * @param string $type the type of the values being compared
 * @param mixed $value the value being compared
 * @param mixed $compareValue another value being compared
 * @return boolean whether the comparison using the specified operator is true.
 */
protected function compareValues($operator, $type, $value, $compareValue)
{
    if ($type === 'number') {
        $value = (float) $value;
        $compareValue = (float) $compareValue;
    } else {
        $value = (string) $value;
        $compareValue = (string) $compareValue;
    }
    switch ($operator) {
        case '==':
            return $value == $compareValue;
        case '===':
            return $value === $compareValue;
        case '!=':
            return $value != $compareValue;
        case '!==':
            return $value !== $compareValue;
        case '>':
            return $value > $compareValue;
        case '>=':
            return $value >= $compareValue;
        case '<':
            return $value < $compareValue;
        case '<=':
            return $value <= $compareValue;
        default:
            return false;
    }
}

这里，无论是数值还是字符串的比较，都是用的比较运算符。

其实针对字符串比较的时候，如果用比较运算符而非比较函数（strcmp）时，当比较的字符串为含有前导0的数字字符串的时候是会有问题的。

比如：’001’ == ‘01’,’000’ == ‘00’，都是为”真”。因为用比较运算符对可以转换为数值的纯数字字符串’001’和’01’进行比较时，它们会被自动的转换为数值1进行比较，这个时候，它们值相等，测试代码：

if('00' == '0') {
    echo '==';
}
else echo '!=';

这里，对compareValues做了调整，针对’==’,’!=’,’>’,’<’,’>=’,’<=’的几种场景，用strcmp。注意对于’===’,’!==’时因为值和类型一起比较，所以没法使用strcmp。

调整后的代码为：

/**
 * Compares two values with the specified operator.
 * @param string $operator the comparison operator
 * @param string $type the type of the values being compared
 * @param mix $value the value being compared
 * @param mix $compareValue another value being compared
 * @return boolean whether the comparison using the specified operator is true.
 */
protected function compareValues($operator, $type, $value, $compareValue) 
{
    if($this->type === 'number') {
        return $this->compareNumbericValues($operator, $type, $value, $compareValue);
    }
    else return $this->compareStringValues($operator, $type, $value, $compareValue);
}
/**
 * Compares two numberic values with the specified operator.
 * @param string $operator the comparison operator
 * @param string $type the type of the values being compared
 * @param numberic $value the value being compared
 * @param numberic $compareValue another value being compared
 * @return boolean whether the comparison using the specified operator is true.
 */
protected function compareNumbericValues($operator, $type, $value, $compareValue)
{
    $value = (float) $value;
    $compareValue = (float) $compareValue;
    
    switch ($operator) {
        case '==':
            return $value == $compareValue;
        case '===':
            return $value === $compareValue;
        case '!=':
            return $value != $compareValue;
        case '!==':
            return $value !== $compareValue;
        case '>':
            return $value > $compareValue;
        case '>=':
            return $value >= $compareValue;
        case '<':
            return $value < $compareValue;
        case '<=':
            return $value <= $compareValue;
        default:
            return false;
    }
}

/**
 * Compares two string values with the specified operator.
 * @param string $operator the comparison operator
 * @param string $type the type of the values being compared
 * @param mix $value the value being compared
 * @param mix $compareValue another value being compared
 * @return boolean whether the comparison using the specified operator is true.
 */
protected function compareStringValues($operator, $type, $value, $compareValue)
{
    $value = (string) $value;
    $compareValue = (string) $compareValue;
    switch ($operator) {
        case '==':
            return strcmp($value, $compareValue) == 0;
        case '===':
            return $value === $compareValue;
        case '!=':
            return strcmp($value, $compareValue) != 0;
        case '!==':
            return $value !== $compareValue;
        case '>':
            return strcmp($value, $compareValue) > 0;
        case '>=':
            return strcmp($value, $compareValue) >= 0;
        case '<':
            return strcmp($value, $compareValue) < 0;
        case '<=':
            return strcmp($value, $compareValue) <= 0;
        default:
            return false;
    }
}

经过测试，修复了上述问题。