what is Yii::app() in php framework yii

Question

I am new to yii. I want to know about Yii::app(). I searched for it, but I am not able to understand it exactly.

Answer 1

Yii is the Yii singleton: http://www.yiiframework.com/doc/api/1.1/Yii

Yii::app() returns the instance of CApplication: http://www.yiiframework.com/doc/api/1.1/CApplication

Which has many handy methods and variables such as user (referenced by Yii::app()->user which was information about the user)

Answer 2

The application object encapsulates the execution context within which a request is processed. Its main task is to collect some basic information about the request, and dispatch it to an appropriate controller for further processing. It also serves as the central place for keeping application-level configuration settings. For this reason, the application object is also called the front-controller.

The application object is instantiated as a singleton by the entry script. The application singleton can be accessed at any place via Yii::app().