Path Aliases
Note: This chapter is under development.
Yii 2.0 expands the usage of path aliases to both file/directory paths and URLs. An alias
must start with an @
symbol so that it can be differentiated from file/directory paths and URLs.
For example, the alias @yii
refers to the Yii installation directory while @web
contains the base URL for the currently running web application. Path aliases are supported in most places in the Yii core code. For example, FileCache::cachePath
can accept both a path alias and a normal directory path.
Path aliases are also closely related to class namespaces. It is recommended that a path
alias should be defined for each root namespace so that Yii's class autoloader can be used without
any further configuration. For example, because @yii
refers to the Yii installation directory,
a class like yii\web\Request
can be autoloaded by Yii. If you use a third party library
such as Zend Framework, you may define a path alias @Zend
which refers to its installation
directory and Yii will be able to autoload any class in this library.
The following aliases are predefined by the core framework:
-
@yii
- framework directory. -
@app
- base path of currently running application. -
@runtime
- runtime directory. -
@vendor
- Composer vendor directory. -
@webroot
- web root directory of currently running web application. -
@web
- base URL of currently running web application.