Yii2 custom AppActiveRecord class used to extend yii\db\ActiveRecord to provide a static find($config) function for backwards-compatibility with Yii 1.1 CActiveRecord->find*(array) functions.

AppActiveRecord.php

<?php
namespace common\models\db;

class AppActiveRecord extends \yii\db\ActiveRecord
{
    /**
     * Override the \yii\db\ActiveRecord::find() static function to allow passing in an array of configuration properties.
     * Also, return a custom AppActiveQuery object that overrides functionality of ActiveQuery and allows Caching.
     * 
     * @param Array|null $config The array of key value pairs to set the ActiveQuery properties on construction.
     * @return \common\models\db\AppActiveQuery
     */
    public static function find($config = null)
    {
        $activeQuery = \Yii::createObject(\common\models\db\AppActiveQuery::className(), [get_called_class()]);
        if(is_array($config) && sizeof($config) > 0) {
            if(isset($config['select']) && is_string($config['select'])) {
                $config['select'] = self::_selectStringToArray($config['select']);
            }
            if(isset($config['orderBy']) && is_string($config['orderBy'])) {
                $config['orderBy'] = self::_orderByStringToArray($config['orderBy']);
            }
            if(!isset($config['from'])) {
                // If the 'from' clause is not specified, create one using the called class Table Name.
                // Include the default table alias of 't' for backwards compatibility. Store 'from' as an array of one string.
                $className = get_called_class();
                $tableName = $className::tableName();
                $config['from'] = [$tableName.' t'];
            }
            foreach($config as $key => $value) {
                $activeQuery->$key = $value;
            }
        }
        return $activeQuery;
    }
    
    public static function _selectStringToArray($string) {
        $array = explode(',',$string);
        if(is_array($array) && sizeof($array) > 0) {
            foreach($array as $index => $column) {
                $array[$index] = trim($column);
            }
        }
        return $array;
    }
    
    public static function _orderByStringToArray($string) {
        $strings = explode(',',$string);
        $orderByArray = array();
        if(is_array($strings) && sizeof($strings) > 0) {
            foreach($strings as $index => $orderBy) {
                $orderBy = trim($orderBy);
                $lastSpacePos = strrpos($orderBy,' ');
                $sort = SORT_ASC;
                if($lastSpacePos!==false) {
                    $column = substr($orderBy,0,$lastSpacePos);
                    $sort = strtoupper(substr($orderBy,$lastSpacePos));
                    if($sort === 'DESC') {
                        $sort = SORT_DESC;
                    }
                }
                else {
                    $column = $orderBy;
                }
                $orderByArray[$column] = $sort;
            }
        }
        return $orderByArray;
    }
}