Many Yii users ask how to create helper classes and functions, and though there are numerous approaches spread out among the forum and wiki articles, this Tutorial tries to bring it all together in one place.
Authentication and Authorization is a good tutorial. Among other topics, it describes basic aspects of Yii's RBAC implementation. But however hard I read the tutorial, I couldn't understand how exactly the hierarchy works. I found how to define authorization hierarchy, how business rules are evaluated, how to configure authManager, but almost nothing about how I should build my hierarchy, in what sequence its nodes are checked, when the checking process stops and what would be the checking result.
In Yii, we can define an action class and ask the controller to instantiate it. And we always create ourselves actions class in rootPath/protected/extensions, and the view file we called in the actions class always are located in rootPath/protected/views/ControllerNAME or rootPath/themes/ThemeNAME/ControllerNAME, then when we use the same actions class in different controllers, we have to copy it from one controller to the other controller, so we also need the "same" view file work for us, here is an example.