In this mini howto I would like to show how to add a required captcha field in the login form, after a defined number of unsuccessfull attempts.
To do this, I will use the blog demo that you have in default Yii download package (path/to/yii/demos/blog).
When using the latest stable jQuery UI themes (1.8.10) with Yii 1.1.6 (which uses 1.8.6) the widgets don't appear (they're invisible but they're there). In order to make them visible you need to change the following line:
First param in CActiveDataProvider could be a string with model name or instance of class. So, you may use CActiveRecord::cache() for cache, but you need set third param to 2, because you should cache 2 queries: counting and get data.
First declare an attribute to store the file name in the model class (either a form model or an active record model).
Also declare a file validation rule for this attribute to ensure a file is uploaded with specific extension name.