O Guia Definitivo do Yii 1.1

Info: Using skin may degrade the performance because Yii needs to look for the skin
file the first time a widget is being created.
Skin is very similar to the global widget customization feature. The main differences are as
follows.
• Skin is more related with the customization of presentational property values;
• A widget can have multiple skins;
• Skin is themeable;
• Using skin is more expensive than using global widget customization.
Registros (Logs)
Yii provides a flexible and extensible logging feature. Messages logged can be classified
according to log levels and message categories. Using level and category filters, selected
messages can be further routed to different destinations, such as files, emails, browser
windows, etc.
Message Logging
Messages can be logged by calling either Yii::log or Yii::trace. The difference between
these two methods is that the latter logs a message only when the application is in debug
mode.
Yii::log($message, $level, $category);
Yii::trace($message, $category);
When logging a message, we need to specify its category and level. Category is a string in
the format ofxxx.yyy.zzz which resembles to the path alias. For example, if a message is
logged in CController, we may use the category system.web.CController. Message level
should be one of the following values:
• trace: this is the level used by Yii::trace. It is for tracing the execution flow of the
application during development.
• info: this is for logging general information.
• profile: this is for performance profile which is to be described shortly.
• warning: this is for warning messages.
• error: this is for fatal error messages.
Message Routing
Messages logged using Yii::log or Yii::trace are kept in memory. We usually need to
display them in browser windows, or save them in some persistent storage such as files,
emails. This is called message routing, i.e., sending messages to different destinations.
In Yii, message routing is managed by a CLogRouter application component. It manages a
set of the so-calledlog routes. Each log route represents a single log destination.
Messages sent along a log route can be filtered according to their levels and categories.