Yii 2.0.0 is released

Oct 12, 2014

Yii 2.0 is finally coming, after more than three years of intensive development with almost 10,000 commits by over 300 authors! Thank you for your support and patience!

As you may have already known, Yii 2.0 is a complete rewrite over the previous version 1.1. We made this choice in order to build a state-of-the-art PHP framework by keeping the original simplicity and extensibility of Yii while adopting the latest technologies and features to make it even better. And today we are very glad to announce that we have achieved our goal.

Below are some useful links about Yii and Yii 2.0:

In the following we will summarize some of the highlights of this long awaited release. You may check out the Getting Started section if you want to rush to try it out first.


Adopting Standards and Latest Technologies

Yii 2.0 adopts PHP namespaces and traits, PSR standards, Composer and Bower. All these make the framework more refreshing and interoperable with other libraries.

Solid Foundation Classes

Like in 1.1, Yii 2.0 supports object properties defined via getters and setters, configurations, events and behaviors. The new implementation is more efficient and expressive. For example, you can write the following code to respond to an event:

$response = new yii\web\Response;
$response->on('beforeSend', function ($event) {
    // respond to the "beforeSend" event here

Yii 2.0 implements the dependency injection container and service locator. It makes the applications built with Yii more customizable and testable.

Development Tools

Yii 2.0 comes with several development tools to make the life of developers easier.

The Yii debugger allows you to examine the runtime internals of your application. It can also be used to do performance profiling to find out the performance bottlenecks in your application.

Like 1.1, Yii 2.0 also provides Gii, a code generation tool, that can cut down a large portion of your development time. Gii is very extensible, allowing you to customize or create different code generators. Gii provides both Web and console interfaces to fit for different user preferences.

The API documentation of Yii 1.1 has received a lot of positive feedback. Many people expressed the wish to create a similar documentation for their applications. Yii 2.0 realizes this with a documentation generator. The generator supports Markdown syntax which allows you to write documentation in a more succinct and expressive fashion.


Yii 2.0 helps you to write more secure code. It has built-in support to prevent SQL injections, XSS attacks, CSRF attacks, cookie tampering, etc. Security experts Tom Worster and Anthony Ferrara even helped us review and rewrite some of the security-related code.


Working with databases has never been easier. Yii 2.0 supports DB migration, database access objects (DAO), query builder and Active Record. Compared with 1.1, Yii 2.0 improves the performance of Active Record and unifies the syntax for querying data via query builder and Active Record. The following code shows how you can query customer data using either query builder or Active Record. As you can see, both approaches use chained method calls which are similar to SQL syntax.

use yii\db\Query;
use app\models\Customer;
$customers = (new Query)->from('customer')
    ->where(['status' => Customer::STATUS_ACTIVE])
$customers = Customer::find()
    ->where(['status' => Customer::STATUS_ACTIVE])

The following code shows how you can perform relational queries using Active Record:

namespace app\models;
use app\models\Order;
use yii\db\ActiveRecord;
class Customer extends ActiveRecord
    public static function tableName()
        return 'customer';
    // defines a one-to-many relation with Order model
    public function getOrders()
        return $this->hasMany(Order::className(), ['customer_id' => 'id']);
// returns the customer whose id is 100
$customer = Customer::findOne(100);
// returns the orders for the customer
$orders = $customer->orders;

And the following code shows how you can update a Customer record. Behind the scene, parameter binding is used to prevent SQL injection attacks, and only modified columns are saved to DB.

$customer = Customer::findOne(100);
$customer->address = '123 Anderson St';
$customer->save();  // executes SQL: UPDATE `customer` SET `address`='123 Anderson St' WHERE `id`=100

Yii 2.0 supports the widest range of databases. Besides the traditional relational databases, Yii 2.0 adds the support for Cubrid, ElasticSearch, Sphinx. It also supports NoSQL databases, including Redis and MongoDB. More importantly, the same query builder and Active Record APIs can be used for all these databases, which makes it an easy task for you to switch among different databases. And when using Active Record, you can even relate data from different databases (e.g. between MySQL and Redis).

For applications with big databases and high performance requirement, Yii 2.0 also provides built-in support for database replication and read-write splitting.


With a few lines of code, Yii 2.0 lets you to quickly build a set of fully functional RESTful APIs that comply to the latest protocols. The following example shows how you can create a RESTful API serving user data.

First, create a controller class app\controllers\UserController and specify app\models\User as the type of model being served:

namespace app\controllers;
use yii\rest\ActiveController;
class UserController extends ActiveController
    public $modelClass = 'app\models\User';

Then, modify the configuration about the urlManager component in your application configuration to serve user data in pretty URLs:

'urlManager' => [
    'enablePrettyUrl' => true,
    'enableStrictParsing' => true,
    'showScriptName' => false,
    'rules' => [
        ['class' => 'yii\rest\UrlRule', 'controller' => 'user'],

That's all you need to do! The API you just created supports:

  • GET /users: list all users page by page;
  • HEAD /users: show the overview information of user listing;
  • POST /users: create a new user;
  • GET /users/123: return the details of the user 123;
  • HEAD /users/123: show the overview information of user 123;
  • PATCH /users/123 and PUT /users/123: update the user 123;
  • DELETE /users/123: delete the user 123;
  • OPTIONS /users: show the supported verbs regarding endpoint /users;
  • OPTIONS /users/123: show the supported verbs regarding endpoint /users/123.

You may access your API with the curl command like the following,

$ curl -i -H "Accept:application/json" "http://localhost/users"

HTTP/1.1 200 OK
Date: Sun, 02 Mar 2014 05:31:43 GMT
Server: Apache/2.2.26 (Unix) DAV/2 PHP/5.4.20 mod_ssl/2.2.26 OpenSSL/0.9.8y
X-Powered-By: PHP/5.4.20
X-Pagination-Total-Count: 1000
X-Pagination-Page-Count: 50
X-Pagination-Current-Page: 1
X-Pagination-Per-Page: 20
Link: <http://localhost/users?page=1>; rel=self, 
      <http://localhost/users?page=2>; rel=next, 
      <http://localhost/users?page=50>; rel=last
Transfer-Encoding: chunked
Content-Type: application/json; charset=UTF-8

        "id": 1,
        "id": 2,


Like 1.1, Yii 2.0 supports a whole range of caching options, from server side caching, such as fragment caching, query caching to client side HTTP caching. They are supported on a variety of caching drivers, including APC, Memcache, files, databases, etc.


In 1.1, you can quickly create HTML forms that support both client side and server side validation. In Yii 2.0, it is even easier working with forms. The following example shows how you can create a login form.

First create a LoginForm model to represent the data being collected. In this class, you will list the rules that should be used to validate the user input. The validation rules will later be used to automatically generate the needed client-side JavaScript validation logic.

use yii\base\Model;
class LoginForm extends Model
    public $username;
    public $password;
     * @return array the validation rules.
    public function rules()
        return [
            // username and password are both required
            [['username', 'password'], 'required'],
            // password is validated by validatePassword()
            ['password', 'validatePassword'],
     * Validates the password.
     * This method serves as the inline validation for password.
    public function validatePassword()
        $user = User::findByUsername($this->username);
        if (!$user || !$user->validatePassword($this->password)) {
            $this->addError('password', 'Incorrect username or password.');

Then create the view code for the login form:

use yii\helpers\Html;
use yii\widgets\ActiveForm;
<?php $form = ActiveForm::begin() ?>
    <?= $form->field($model, 'username') ?>
    <?= $form->field($model, 'password')->passwordInput() ?>
    <?= Html::submitButton('Login') ?>
<? ActiveForm::end() ?>

Authentication and Authorization

Like 1.1, Yii 2.0 provides built-in support for user authentication and authorization. It supports features such as login, logout, cookie-based and token-based authentication, access control filter and role-based access control (RBAC).

Yii 2.0 also provides the ability of the authentication via external credentials providers. It supports OpenID, OAuth1 and OAuth2 protocols.


Yii 2.0 comes with a rich set of user interface elements, called widgets, to help you quickly build interactive user interfaces. It has built-in support for Bootstrap widgets and jQuery UI widgets. It also provides commonly used widgets such as pagers, grid view, list view, detail, all of which make Web application development a truly speedy and enjoyable process. For example, with the following lines of code, you can create a fully functional jQuery UI date picker in Russian:

use yii\jui\DatePicker;
echo DatePicker::widget([
    'name' => 'date',
    'language' => 'ru',
    'dateFormat' => 'yyyy-MM-dd',


Yii 2.0 provides many useful helper classes to simplify some common tasks. For example, the Html helper includes a set of methods to create different HTML tags, and the Url helper lets you more easily creates various URLs, like shown below:

use yii\helpers\Html;
use yii\helpers\Url;
// creates a checkbox list of countries
echo Html::checkboxList('country', 'USA', $countries);
// generates a URL like "/index?r=site/index&src=ref1#name"
echo Url::to(['site/index', 'src' => 'ref1', '#' => 'name']);


Yii has strong support for internationalization, as it is being used all over the world. It supports message translation as well as view translation. It also supports locale-based plural forms and data formatting, which complies to the ICU standard. For example,

// message translation with date formatting
echo \Yii::t('app', 'Today is {0, date}', time());
// message translation with plural forms
echo \Yii::t('app', 'There {n, plural, =0{are no cats} =1{is one cat} other{are # cats}}!', ['n' => 0]);

Template Engines

Yii 2.0 uses PHP as its default template language. It also supports Twig and Smarty through its template engine extensions. And it is also possible for you to create extensions to support other template engines.


Yii 2.0 strengthens the testing support by integrating Codeception and Faker. It also comes with a fixture framework which coupled with DB migrations, allows you to manage your fixture data more flexible.

Application Templates

To further cut down your development time, Yii is released with two application templates, each being a fully functional Web application. The basic application template can be used as a starting point for developing small and simple Web sites, such as company portals, personal sites. The advanced application template is more suitable for building large enterprise applications that involve multiple tiers and a big developer team.


While Yii 2.0 already provides many powerful features, one thing that makes Yii even more powerful is its extension architecture. Extensions are redistributable software packages specifically designed to be used in Yii applications and provide ready-to-use features. Many built-in features of Yii are provided in terms of extensions, such as mailing, Bootstrap. Yii also boasts a big user-contributed extension library consisting of almost 1700 extensions, as the time of this writing. We also find there are more than 1300 Yii-related packages on packagist.org.

Getting Started

To get started with Yii 2.0, simply run the following commands:

# install the composer-asset-plugin globally. This needs to be run only once.
php composer.phar global require "fxp/composer-asset-plugin:1.0.0-beta3"

# install the basic application template
php composer.phar create-project yiisoft/yii2-app-basic basic 2.0.0

The above commands assume you already have Composer. If not, please follow the Composer installation instructions to install it.

Note that you may be prompted to enter your GitHub username and password during the installation process. This is normal. Just enter them and continue.

With the above commands, you have a ready-to-use Web application that may be accessed through the URL http://localhost/basic/web/index.php.


If you are upgrading from previous Yii 2.0 development releases (e.g. 2.0.0-beta, 2.0.0-rc), please follow the upgrade instructions.

If you are upgrading from Yii 1.1, we have to warn you that it will not be smooth, mainly because Yii 2.0 is a complete rewrite with many syntax changes. However, most of your Yii knowledge still apply in 2.0. Please read the upgrade instructions to learn the major changes introduced in 2.0.


Yii 2.0 has a definitive guide as well as a class reference. The definitive guide is also being translated into many languages.

There are also a few books about Yii 2.0 just published or being written by famous writers such as Larry Ullman. Larry even spends his time helping us polish the definitive guide. And Alexander Makarov is coordinating a community-contributed cookbook about Yii 2.0, following his well-received cookbook about Yii 1.1.


We hereby thank everyone who has contributed to Yii. Your support and contributions are invaluable!