Backend Development
PHP Tutorial
Detailed explanation of the loading process and principle of Facade in Laravel
Detailed explanation of the loading process and principle of Facade in Laravel
Facade is actually a static proxy of a class in the container. It allows you to statically call any method of any object stored in the container. This article mainly introduces you to the loading process and principle of Facade in Laravel. For relevant information, friends in need can refer to it. I hope to be helpful.
Preface
This article mainly introduces the relevant content about the Facade loading process and principles in Laravel, and shares it for your reference and study. Not much to say below, let’s take a look at the detailed introduction.
Introduction
Facades (pronounced: /fəˈsäd/) provide a " Static" interface. You don't have to use a bunch of namespaces or instantiate the object to access its specific methods.
use Config;
class Test
{
public function index()
{
return Config::get('app.name');
}
}Facade startup and registration
Facade startup boot is registered in Illuminate\Foundation\Bootstrap\RegisterFacades.
public function bootstrap(Application $app)
{
Facade::clearResolvedInstances();
Facade::setFacadeApplication($app);
AliasLoader::getInstance(array_merge(
$app->make('config')->get('app.aliases', []),
$app->make(PackageManifest::class)->aliases()
))->register();
}The default alias configuration is read from aliases under the app configuration file. PackageManifest is a new package automatic discovery rule added by laravel 5.5. Here we do not consider the aliases provided by the PackageManifest package for the time being.
Among them, array_merge returns an array in the following format:
"App" => "Illuminate\Support\Facades\App" "Artisan" => "Illuminate\Support\Facades\Artisan" "Auth" => "Illuminate\Support\Facades\Auth" "Blade" => "Illuminate\Support\Facades\Blade" ...
The above code will register all facades for automatic loading through AliasLoader. The core is php's spl_autoload_register.
/**
* Prepend the load method to the auto-loader stack.
*
* @return void
*/
protected function register()
{
if (! $this->registered) {
spl_autoload_register([$this, 'load'], true, true);
$this->registered = true;
}
}After the registration is completed, all subsequent use classes will be automatically loaded through the load function.
Note: When defining spl_autoload_register here, the last parameter is passed true. When this parameter is true, spl_autoload_register() will add the function to the head of the queue instead of the tail. (This function is used first to complete automatic loading)
In other words,
<?php
use Config;
use App\User;
class Test
{
public function index()
{
Config::get('app.name');
new User();
}
}No matter what we use is a specific existing class (App\User) or an alias (Config), Automatic loading will be completed first through the load function. When the function returns false, automatic loading will be completed by other automatic loading functions (such as composer psr-4).
In the load method of AliasLoader, the class_alias function is mainly used to implement automatic loading of aliases.
public function load($alias)
{
if (isset($this->aliases[$alias])) {
return class_alias($this->aliases[$alias], $alias);
}
}About class_alias Here is an official example:
class foo { }
class_alias('foo', 'bar');
$a = new foo;
$b = new bar;
// the objects are the same
var_dump($a == $b, $a === $b); //true
var_dump($a instanceof $b); //false
// the classes are the same
var_dump($a instanceof foo); //true
var_dump($a instanceof bar); //true
var_dump($b instanceof foo); //true
var_dump($b instanceof bar); //trueLoading of Facade
When we are in When using Facade, for example:
<?php
use Config;
class Test
{
public function index()
{
Config::get('app.name');
}
}actually loads the Illuminate\Support\Facades\Config class (because we have registered class_alias), which is equivalent to:
<?php
use Illuminate\Support\Facades\Config;
class Test
{
public function index()
{
Config::get('app.name');
}
}And all Facades are Inherited from the Illuminate\Support\Facades\Facade class, a __callStatic method is defined in this base class, so that we can easily use Facade (without instantiation).
<?php
public static function __callStatic($method, $args)
{
$instance = static::getFacadeRoot();
if (! $instance) {
throw new RuntimeException('A facade root has not been set.');
}
return $instance->$method(...$args);
}The getFacadeRoot method is used to obtain the specific instance column of the alias class. We know that all Facade classes need to define a getFacadeAccessor method. Possible return values of this method are:
String type string (such as config, db)
String type string-like ( Such as App\Service\SomeService)
Object specific instantiated object
Closure closure
For example, the getFacadeAccessor method of Config Facade is as follows:
protected static function getFacadeAccessor()
{
return 'config';
}The getFacadeRoot method will retrieve the corresponding real column object from the container based on the return value of getFacadeAccessor() .
public static function getFacadeRoot()
{
$name = static::getFacadeAccessor();
if (is_object($name)) {
return $name;
}
if (isset(static::$resolvedInstance[$name])) {
return static::$resolvedInstance[$name];
}
return static::$resolvedInstance[$name] = static::$app[$name];
}Since the actual column of config has been registered in the APP container
<?php //Illuminate\Foundation\Bootstrap/LoadConfiguration $app->instance('config', $config = new Repository($items));
, so \Config::get('app.name', 'dafault) actually accessed It is the get('app.name', 'default') method of the Repository actual column.
Related recommendations:
##Detailed explanation of Laravel using salt and password authentication by modifying Auth
Detailed explanation of Laravel’s localization module
Detailed explanation of how to rewrite resource routing in Laravel
The above is the detailed content of Detailed explanation of the loading process and principle of Facade in Laravel. For more information, please follow other related articles on the PHP Chinese website!
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1668
14
1428
52
1329
25
1273
29
1256
24
Laravel Introduction Example
Apr 18, 2025 pm 12:45 PM
Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.
Solve caching issues in Craft CMS: Using wiejeben/craft-laravel-mix plug-in
Apr 18, 2025 am 09:24 AM
When developing websites using CraftCMS, you often encounter resource file caching problems, especially when you frequently update CSS and JavaScript files, old versions of files may still be cached by the browser, causing users to not see the latest changes in time. This problem not only affects the user experience, but also increases the difficulty of development and debugging. Recently, I encountered similar troubles in my project, and after some exploration, I found the plugin wiejeben/craft-laravel-mix, which perfectly solved my caching problem.
How to learn Laravel How to learn Laravel for free
Apr 18, 2025 pm 12:51 PM
Want to learn the Laravel framework, but suffer from no resources or economic pressure? This article provides you with free learning of Laravel, teaching you how to use resources such as online platforms, documents and community forums to lay a solid foundation for your PHP development journey from getting started to master.
Laravel user login function
Apr 18, 2025 pm 12:48 PM
Laravel provides a comprehensive Auth framework for implementing user login functions, including: Defining user models (Eloquent model), creating login forms (Blade template engine), writing login controllers (inheriting Auth\LoginController), verifying login requests (Auth::attempt) Redirecting after login is successful (redirect) considering security factors: hash passwords, anti-CSRF protection, rate limiting and security headers. In addition, the Auth framework also provides functions such as resetting passwords, registering and verifying emails. For details, please refer to the Laravel documentation: https://laravel.com/doc
What versions of laravel are there? How to choose the version of laravel for beginners
Apr 18, 2025 pm 01:03 PM
In the Laravel framework version selection guide for beginners, this article dives into the version differences of Laravel, designed to assist beginners in making informed choices among many versions. We will focus on the key features of each release, compare their pros and cons, and provide useful advice to help beginners choose the most suitable version of Laravel based on their skill level and project requirements. For beginners, choosing a suitable version of Laravel is crucial because it can significantly impact their learning curve and overall development experience.
Laravel framework installation method
Apr 18, 2025 pm 12:54 PM
Article summary: This article provides detailed step-by-step instructions to guide readers on how to easily install the Laravel framework. Laravel is a powerful PHP framework that speeds up the development process of web applications. This tutorial covers the installation process from system requirements to configuring databases and setting up routing. By following these steps, readers can quickly and efficiently lay a solid foundation for their Laravel project.
How to view the version number of laravel? How to view the version number of laravel
Apr 18, 2025 pm 01:00 PM
The Laravel framework has built-in methods to easily view its version number to meet the different needs of developers. This article will explore these methods, including using the Composer command line tool, accessing .env files, or obtaining version information through PHP code. These methods are essential for maintaining and managing versioning of Laravel applications.
The difference between laravel and thinkphp
Apr 18, 2025 pm 01:09 PM
Laravel and ThinkPHP are both popular PHP frameworks and have their own advantages and disadvantages in development. This article will compare the two in depth, highlighting their architecture, features, and performance differences to help developers make informed choices based on their specific project needs.
