Yii 2.0 RC is released

Sep 28, 2014

We are very pleased to announce the release of Yii 2.0 RC (Release Candidate). You may follow the instructions on yiiframework.com to install or upgrade to this version.

This RC release includes about 100 bug fixes and 200 new features and enhancements. It is a result of five months of intensive development since the prior Beta release. During this period, we have received a lot of help from the Yii community users. We hereby thank everyone who has contributed to Yii and made this release possible. You are the best!

Commonly Asked Questions

  • What does 2.0 RC mean? RC means Release Candidate. It is the last development release before the GA (General Availability) release. The remaining work for us to release GA mainly include minor issue fixing and documentation.

  • When will 2.0 GA be released? It depends on the feedback we receive about this RC release. We have a tentative plan to release 2.0 GA in about two weeks, if the RC version is proven to be stable enough.

  • Can I use RC for my projects? Yes, and we strongly recommend you to try it out in your new projects and give us feedback about it. As 2.0 GA is just around the corner, we suggest you do not use RC for production use because we may still introduce breaking changes, even though this possibility is very small.

  • Are there any documentation for 2.0? Yes, the Definitive Guide which is the most comprehensive and in-depth tutorial about Yii 2.0, and the API documentation which is the reference that you would use to look up the usage of individual classes in the framework.

  • How can I upgrade my application written in 1.1 to 2.0? Please refer to Upgrading from Yii 1.1. Note that since 2.0 is a complete rewrite of 1.1, the upgrade will not be trivial. If your application in 1.1 is already running stably, we suggest you keep using 1.1 unless you have enough time and resource to do the upgrade.

  • How can I upgrade from 2.0 Beta or Alpha? Please follow the instructions in UPGRADE.

  • How can I follow the 2.0 development? All development activities of Yii 2.0 occur on GitHub: https://github.com/yiisoft/yii2. You may watch or star this project to receive development updates. You may also follow our Twitter updates at https://twitter.com/yiiframework and/or join our Facebook Group.

Major Enhancements in 2.0 RC

In this release, we have included many useful features and changes. Below we summarize some of the most important ones. Complete list of changes in this release can be found in CHANGELOG. Please read the Definitive Guide if you want to learn what you can do with Yii 2.0 in general.


Several security experts, including Tom Worster and Anthony Ferrara, have helped review the Yii code about its security aspect and left many important feedbacks on how to improve the security of Yii in general. Tom even helped us rewrite some of the security code, which results in better key generation and encryption, protection from timing attacks, and many other things.

To support customization of some security features, we have turned the previous Security helper class into the security application component. As a result, you can access security-related features through expressions such as Yii::$app->security->encrypt().

We have also made several other minor yet important changes to further improve the security of Yii. For example, httpOnly is now turned on for all cookies by default; CSRF tokens can be stored in sessions instead of cookies if you set yii\web\Request::enableCsrfCookie to be false.


Database Replication and Read-Write Splitting

Yii now has built-in support for database replication and read-write splitting. With database replication, data are replicated from the so-called master servers to slave servers. All writes and updates must take place on the master servers, while reads may take place on the slave servers. To use this feature, simply configure your DB connection like the following:

    'class' => 'yii\db\Connection',
    // configuration for the master
    'dsn' => 'dsn for master server',
    'username' => 'master',
    'password' => '',
    // common configuration for slaves
    'slaveConfig' => [
        'username' => 'slave',
        'password' => '',
    // list of slave configurations
    'slaves' => [
        ['dsn' => 'dsn for slave server 1'],
        ['dsn' => 'dsn for slave server 2'],
        ['dsn' => 'dsn for slave server 3'],

With this configuration, you can continue writing DB query code as usual. If a query is fetching data from database, one of the slaves will be used automatically to perform the query (a simple load balancing algorithm is implemented regarding slave selection); if the query is updating or inserting data into database, the master will be used.


There are several enhancements about using DB transactions.

First, you can now work with transactions in a callback style like the following:

$connection->transaction(function() {
    $order = new Order($customer);

This is equivalent to the following lengthy code:

$transaction = $connection->beginTransaction();
try {
    $order = new Order($customer);
} catch (\Exception $e) {
    throw $e;

Second, a few events are triggered for transactions. For example, a beginTransaction event is triggered by a DB connection when you start a new transaction; and a commitTransaction event is triggered when the transaction is successfully committed. You can respond to these events to perform some preprocessing and post-processing tasks when using transactions.

Last, you can set transaction isolation levels (e.g. READ COMMITTED) when starting a new transaction. For example,

$transaction = $connection->beginTransaction(Transaction::READ_COMMITTED);

Building Query Conditions

You can use arbitrary operators when building a query condition. In the following example, the operator >= is used to build a query condition age >= 30. Yii will properly quote the column name and use parameter binding to handle the value.

$query = new \yii\db\Query;
$query->where(['>=', 'age', 30]);

When building an in or not condition, you can use sub-queries like the following:

$subquery = (new \yii\db\Query)
    ->where(['>=', 'age', 30]);
// fetch orders that are placed by customers who are older than 30  
$orders = (new \yii\db\Query)
    ->where(['in', 'customer_id', $subquery])

Asset Management

Yii is embracing Bower and NPM packages. It uses the excellent Composer Asset Plugin to manage the dependencies on Bower/NPM packages (e.g. jQuery, jQuery UI, Bootstrap) through the interface of Composer.

Because of this change, it is required that you install the plugin first by running the following command (once for all), before you start to install or upgrade to Yii 2.0 RC:

php composer.phar global require "fxp/composer-asset-plugin:1.0.0-beta2"

Now if you run the following command, you will be able to install the jQuery Bower package under the vendor directory:

php composer.phar require bower-asset/jquery:2.1.*

Please refer to the Definitive Guide about assets for more details about asset management in general.

Data Formatting

We did significant refactoring of the data formatting classes and the previous yii\base\Formatter and yii\i18n\Formatter classes into a single one yii\i18n\Formatter. The new formatter class provides a consistent interface regardless whether the PHP intl extension is installed or not. If the extension is not installed, it will fallback nicely to support data formatting without internationalization.

We also unified the way of specifying date and time formats to be the ICU format. Classes such as DateValidator and the JUI DatePicker all use such format by default. You can, however, still use PHP date format by prefxing it with php:. For example,

$formatter = Yii::$app->formatter;
$value = time();
echo $formatter->asDate($value, 'MM/dd/yyyy'); // same as date('m/d/Y', $value)
echo $formatter->asDate($value, 'php:Y/m/d');  // same as date('Y/m/d', $value)
echo $formatter->asDate($value, 'long');       // same as date('F j, Y', $value)


Several improvements were made to the JavaScript code for ActiveForm.

Instead of using callbacks to inject code during the client-side validation process, a set of events are triggered. You can easily write JavaScript code to respond to these events. For example,

$('#myform').on('beforeValidate', function (event, messages, deferreds) {
    // called before validating the whole form when the submit button is clicked
    // You may do some custom validation here

$('#myform').on('beforeSubmit', function () {
    // called after all validations pass and the form should be submitted
    // You may perform AJAX form submission here. Make sure you return false to prevent the default form submission.

Deferred validation is also supported. In the above example, the deferreds parameter for the beforeValidate event allows you to add new Deferred object. Utilizing this deferred validation support, FileValidator and ImageValidator both support client-side validation now.

Several methods in the ActiveForm JavaScript code are now exposed so that you can more easily build dynamic forms on the client and support validation of input fields that are dynamically created. For example, the following JavaScript can be used to add validation support for a newly created input field "address":

$('#myform').yiiActiveForm('add', {
    'id': 'address',
    'name': 'address',
    'container': '.field-address',
    'input': '#address',
    'error': '.field-address .help-block'

Logging and Error Handling

You can now use arrays or objects as log messages. The default log targets will automatically convert them into text display; while your customize log target classes can handle such complex data specially.

InvalidCallException, InvalidParamException, UnknownMethodException are now extending from SPL BadMethodCallException to make exception hierarchy more logical.

Exception display is improved by showing the arguments in the stack trace method class.

Development Tools

The Yii debugger is a useful tool to show you detailed debug information when a Yii application runs. We have added a new debugger panel to show the loaded asset bundles and their content.

The Yii code generator Gii can now be run as a console command! Previously it only provides a Web interface, which although very intuitive and easy to use, is not liked by some hardcore users. Now everyone should be happy. More importantly, you can still create a new Gii generator as usual, and it can be used in both Web and console modes without any extra work.

To try Gii in console mode, run the following commands:

# change path to your application's base path
cd path/to/AppBasePath

# show help information about Gii
yii help gii

# show help information about the model generator in Gii
yii help gii/model

# generate City model from city table
yii gii/model --tableName=city --modelClass=City


We have added a new behavior yii\behaviors\SluggableBehavior which can fill the specified model attribute with the transliterated and adjusted version so that it can be used in URLs. You may use this behavior like follows,

use yii\behaviors\SluggableBehavior;
public function behaviors()
   return [
           'class' => SluggableBehavior::className(),
           'attribute' => 'title',
           // 'slugAttribute' => 'alias',   // store slug in "alias" column
           // 'ensureUnique' => true,       // ensure generation of unique slugs

Behaviors can now be specified and attached anonymously. For example,

    'myBehavior1' => new MyBehavior,  // a named behavior
    MyBehavior::className(),          // an anonymous behavior

Template Engines

Both Smarty and Twig view renderers have received significant improvements. Special syntaxes are introduced for many Yii concepts, and we have received feedback that these new syntaxes allow one to work with Smarty and Twig as efficiently as normal PHP templates. To learn more about new syntaxes, please refer to the Definitive Guide.