guyber
(Vicsaints3rd)
1
Hi All,
I have big enterprise application coded in Yii 1.1.14, and this application has been serving us for almost 10 yrs already.
Now we are planning to upgrade to Yii 2. Could you guys help me on the best steps to do in migrating to Yii 2.
Is there generator or extension that can help me.
Sorry for my bad English 
Thank you in advance for your help.
There is official document available online
Here are some important code snippets:
1) Modification of entry script:
// include the customized Yii class described below
require(__DIR__ . '/../components/Yii.php');
// configuration for Yii 2 application
$yii2Config = require(__DIR__ . '/../config/yii2/web.php');
new yii\web\Application($yii2Config); // Do NOT call run()
// configuration for Yii 1 application
$yii1Config = require(__DIR__ . '/../config/yii1/main.php');
Yii::createWebApplication($yii1Config)->run();
2) Combination of Yii classes:
$yii2path = '/path/to/yii2';
require($yii2path . '/BaseYii.php'); // Yii 2.x
$yii1path = '/path/to/yii1';
require($yii1path . '/YiiBase.php'); // Yii 1.x
class Yii extends \yii\BaseYii
{
// copy-paste the code from YiiBase (1.x) here
}
Yii::$classMap = include($yii2path . '/classes.php');
// register Yii 2 autoloader via Yii 1
Yii::registerAutoloader(['Yii', 'autoload']);
// create the dependency injection container
Yii::$container = new yii\di\Container;
Usage of Yii class:
echo get_class(Yii::app()); // outputs 'CWebApplication'
echo get_class(Yii::$app); // outputs 'yii\web\Application'