RestService::getFilter: Bitrix method

      
<?php 
//  Bitrix\Bizproc\RestService :: getFilter()
//  /dist/bitrix/modules/bizproc/lib/restservice.php:1268

    private static function getFilter($rules, $fields, array $datetimeFieldsList = array())
    {
        $filter = array();
        if (!empty($rules) && is_array($rules))
        {
            foreach ($rules as $key => $value)
            {
                if (preg_match('/^([^a-zA-Z]*)(.*)/', $key, $matches))
                {
                    $operation = $matches[1];
                    $field = $matches[2];

                    if (in_array($operation, static::$allowedOperations, true) && isset($fields[$field]))
                    {
                        if (in_array($field, $datetimeFieldsList))
                            $value = \CRestUtil::unConvertDateTime($value);

                        $filter[$operation.$fields[$field]] = $value;
                    }
                }
            }
        }

        return $filter;
    }