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.
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.
Validators extending from CValidator all have a property named message. You can set this property in the corresponding validation rule to customize the error message. For example, the following validation rule uses an error message that is different from the default one:
Update: This wiki has been rewritten to be in line with Yii 1.1.14. Since many of the detailed complexities are now handled by Yii, the article focuses on how the crypt() built-in function works and why it's important to use it correctly.