[Laravel 5.2 Document] architecture--façade (facades)

1. Introduction

The façade provides a "static" interface for the binding class in the application's service container. Laravel has many facades built in, and you may be using them without knowing. Laravel's façade serves as a "static proxy" for the underlying class in the service container, providing easier to test, more flexible, concise, and expressive syntax than traditional static methods in maintenance.

2. Use the façade

In the context of the Laravel application, the façade is a class that provides access to objects in the container. The mechanism is implemented by the facade class, and the Laravel comes with the façade, and the custom façade that is created, inherits from the Illuminate\support\facades\facade base class.

The façade class only needs to implement one method: Getfacadeaccessor. It is the Getfacadeaccessor method that defines what is parsed from the container and then facade the base class using the Magic Method __callstatic () to invoke the parsed object from your façade.

In the following example, we will call the Laravel cache system, and after browsing the code, you might think that we have called the cache's static method get:

 
  $user]);}    }

Note that we introduced the cache façade in the top position. The façade acts as an agent to access the implementation of the underlying Illuminate\contracts\cache\factory interface. All calls to the façade will be passed to the underlying instance of the Laravel cache service.

If we look at the source code of the Illuminate\support\facades\cache class, we will find that there is no static method get:

Class Cache extends facade{    /**     * Get component Registration name     *     * @return String */    protected static function Getfacadeaccessor () {         return ' cache ';     }}

The cache façade inherits the facade base class and defines the Getfacadeaccessor method, which works by returning the alias of the service container binding class, and when the user references any static method of the cache class, Laravel resolves the cache binding from the service container. Then all the request methods (in this case, get) are invoked on the parsed object.

3. List of façade classes

Each façade and its underlying class are listed below, which is a useful tool for delving into the API documentation for a given root façade. The service container binding key is also included:

Façade	class	service Container binding aliases
App	Illuminate\foundation\application	App
Artisan	Illuminate\console\application	Artisan
Auth	Illuminate\auth\authmanager	Auth
Auth (Instance)	Illuminate\auth\guard
Blade	Illuminate\view\compilers\bladecompiler	Blade.compiler
Bus	Illuminate\contracts\bus\dispatcher
Cache	Illuminate\cache\repository	Cache
Config	Illuminate\config\repository	Config
Cookies	Illuminate\cookie\cookiejar	Cookies
Crypt	Illuminate\encryption\encrypter	Encrypter
Db	Illuminate\database\databasemanager	Db
DB (Instance)	Illuminate\database\connection
Event	Illuminate\events\dispatcher	Events
File	Illuminate\filesystem\filesystem	Files
Hash	Illuminate\contracts\hashing\hasher	Hash
Input	Illuminate\http\request	Request
Lang	Illuminate\translation\translator	Translator
Log	Illuminate\log\writer	Log
Mail	Illuminate\mail\mailer	Mailer
Password	Illuminate\auth\passwords\passwordbroker	Auth.password
Queue	Illuminate\queue\queuemanager	Queue
Queue (Instance)	Illuminate\queue\queueinterface
Queue (Base Class)	Illuminate\queue\queue
Redirect	Illuminate\routing\redirector	redirect
Redis	Illuminate\redis\database	Redis
Request	Illuminate\http\request	Request
Response	Illuminate\contracts\routing\responsefactory
Route	Illuminate\routing\router	Router
Schema	Illuminate\database\schema\blueprint
Session	Illuminate\session\sessionmanager	Session
Session (Instance)	Illuminate\session\store
Storage	Illuminate\contracts\filesystem\factory	FileSystem
Url	Illuminate\routing\urlgenerator	Url
Validator	Illuminate\validation\factory	Validator
Validator (Instance)	Illuminate\validation\validator
View	Illuminate\view\factory	View
View (Instance)	Illuminate\view\view

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