The app class is responsible for path management, class location and class loading.
Make sure you follow the File and Classname Conventions.
CakePHP is organized around the idea of packages, each class belongs to a
package or folder where other classes reside. You can configure each package
location in your application using App::build('APackage/SubPackage', $paths)
to inform the framework where should each class be loaded. Almost every class in
the CakePHP framework can be swapped with your own compatible implementation. If
you wish to use you own class instead of the classes the framework provides,
just add the class to your libs folder emulating the directory location of where
CakePHP expects to find it.
For instance if you’d like to use your own HttpSocket class, put it under:
Once you’ve done this App will load your override file instead of the file
static App::uses(string $class, string $package)
Classes are lazily loaded in CakePHP, however before the autoloader
can find your classes you need to tell App, where it can find the files.
By telling App which package a class can be found in, it can properly locate
the file and load it the first time a class is used.
Some examples for common types of classes are:
- App::uses('PostsController', 'Controller');
- App::uses('AuthComponent', 'Controller/Component');
- App::uses('MyModel', 'Model');
- App::uses('TreeBehavior', 'Model/Behavior');
- App::uses('ThemeView', 'View');
- App::uses('HtmlHelper', 'View/Helper');
- App::uses('PaymentProcessor', 'Lib');
- App::uses('Textile', 'Vendor');
- App::uses('String', 'Utility');
So basically the second param should simply match the folder path of the class file in core or app.
Loading vendors usually means you are loading packages that do not follow
conventions. For most vendor packages using App::import() is
Loading files from plugins
Loading classes in plugins works much the same as loading app and
core classes except you must specify the plugin you are loading
// Load the class Comment in app/Plugin/PluginName/Model/Comment.php
// Load the class CommentComponent in app/Plugin/PluginName/Controller/Component/CommentComponent.php
Finding paths to packages using App::path()
static App::path(string $package, string $plugin = null)
Used to read information stored path:
// return the model paths in your application
This can be done for all packages that are apart of your application. You
can also fetch paths for a plugin:
// return the component paths in DebugKit
Get all the currently loaded paths from App. Useful for inspecting or
storing all paths App knows about. For a paths to a specific package
static App::core(string $package)
Used for finding the path to a package inside CakePHP:
// Get the path to Cache engines.
static App::location(string $className)
Returns the package name where a class was defined to be located at.
Adding paths for App to find packages in
static App::build(array $paths = array(), mixed $mode = App::PREPEND)
Sets up each package location on the file system. You can configure multiple
search paths for each package, those will be used to look for files one
folder at a time in the specified order. All paths should be terminated
with a directory separator.
Adding additional controller paths for example would alter where CakePHP
looks for controllers. This allows you to split your application up across
//will setup a new search path for the Model package
App::build(array('Model' => array('/a/full/path/to/models/')));
//will setup the path as the only valid path for searching models
App::build(array('Model' => array('/path/to/models/')), App::RESET);
//will setup multiple search paths for helpers
App::build(array('View/Helper' => array('/path/to/helpers/', '/another/path/')));
If reset is set to true, all loaded plugins will be forgotten and they will
be needed to be loaded again.
App::build(array('controllers' => array('/full/path/to/controllers')));
App::build(array('Controller' => array('/full/path/to/Controller')));
App::build(array('helpers' => array('/full/path/to/views/helpers')));
App::build(array('View/Helper' => array('/full/path/to/View/Helper')));
Changed in version 2.0: App::build() will not merge app paths with core paths anymore.
Add new packages to an application
App::build() can be used to add new package locations. This is useful
when you want to add new top level packages or, sub-packages to your
'Service' => array('%s' . 'Service' . DS)
The %s in newly registered packages will be replaced with the
APP path. You must include a trailing / in registered
packages. Once packages are registered, you can use App::build() to
append/prepend/reset paths like any other package.
Changed in version 2.1: Registering packages was added in 2.1
Finding which objects CakePHP knows about
static App::objects(string $type, mixed $path = null, boolean $cache = true)
|Return type:||mixed Returns an array of objects of the given type or false if incorrect.
You can find out which objects App knows about using
App::objects('Controller') for example to find which application controllers
App knows about.
//returns array('DebugKit', 'Blog', 'User');
//returns array('PagesController', 'BlogController');
You can also search only within a plugin’s objects by using the plugin dot syntax.:
// returns array('MyPluginPost', 'MyPluginComment');
Changed in version 2.0.
- Returns array() instead of false for empty results or invalid types
- Does not return core objects anymore, App::objects('core') will
- Returns the complete class name
static App::pluginPath(string $plugin)
Plugins can be located with App as well. Using App::pluginPath('DebugKit');
for example, will give you the full path to the DebugKit plugin:
$path = App::pluginPath('DebugKit');
static App::themePath(string $theme)
Themes can be found App::themePath('purple');, would give the full path to the
Including files with App::import()
static App::import(mixed $type = null, string $name = null, mixed $parent = true, array $search = array(), string $file = null, boolean $return = false)
At first glance App::import seems complex, however in most use
cases only 2 arguments are required.
This method is equivalent to require‘ing the file.
It is important to realize that the class subsequently needs to be initialized.
// The same as require('Controller/UsersController.php');
// We need to load the class
$Users = new UsersController();
// If we want the model associations, components, etc to be loaded
All classes that were loaded in the past using App::import(‘Core’, $class) will need to be
loaded using App::uses() referring to the correct package. This change has provided large
performance gains to the framework.
Changed in version 2.0.
- The method no longer looks for classes recursively, it strictly uses the values for the
paths defined in App::build()
- It will not be able to load App::import('Component', 'Component') use
- Using App::import('Lib', 'CoreClass'); to load core classes is no longer possible.
- Importing a non-existent file, supplying a wrong type or package name, or
null values for $name and $file parameters will result in a false return
- App::import('Core', 'CoreClass') is no longer supported, use
App::uses() instead and let the class autoloading do the rest.
- Loading Vendor files does not look recursively in the vendors folder, it
will also not convert the file to underscored anymore as it did in the
Overriding classes in CakePHP
You can override almost every class in the framework, exceptions are the
App and Configure classes. Whenever you like to
perform such overriding, just add your class to your app/Lib folder mimicking
the internal structure of the framework. Some examples to follow
- To override the Dispatcher class, create app/Lib/Routing/Dispatcher.php
- To override the CakeRoute class, create app/Lib/Routing/Route/CakeRoute.php
- To override the Model class, create app/Lib/Model/Model.php
When you load the replaced files, the app/Lib files will be loaded instead of
the built-in core classes.
Loading Vendor Files
You can use App::uses() to load classes in vendors directories. It follows
the same conventions as loading other files:
// Load the class Geshi in app/Vendor/Geshi.php
To load classes in subdirectories, you’ll need to add those paths
// Load the class ClassInSomePackage in app/Vendor/SomePackage/ClassInSomePackage.php
App::build(array('Vendor' => array(APP . 'Vendor' . DS . 'SomePackage')));
Your vendor files may not follow conventions, have a class that differs from
the file name or does not contain classes. You can load those files using
App::import(). The following examples illustrate how to load vendor
files from a number of path structures. These vendor files could be located in
any of the vendor folders.
To load app/Vendor/geshi.php:
The geshi file must be a lower-case file name as Cake will not
find it otherwise.
To load app/Vendor/flickr/flickr.php:
To load app/Vendor/some.name.php:
App::import('Vendor', 'SomeName', array('file' => 'some.name.php'));
To load app/Vendor/services/well.named.php:
App::import('Vendor', 'WellNamed', array('file' => 'services' . DS . 'well.named.php'));
It wouldn’t make a difference if your vendor files are inside your /vendors
directory. Cake will automatically find it.
To load vendors/vendorName/libFile.php:
App::import('Vendor', 'aUniqueIdentifier', array('file' => 'vendorName' . DS . 'libFile.php'));
App Init/Load/Shutdown Methods
Initializes the cache for App, registers a shutdown function.
static App::load(string $className)
Method to handle the automatic class loading. It will look for each class’
package defined using App::uses() and with this information it
will resolve the package name to a full path to load the class from. File
name for each class should follow the class name. For instance, if a class
is name MyCustomClass the file name should be MyCustomClass.php
Object destructor. Writes cache file if changes have been made to the