Do you know where Laravel’s $this->app and app() come from?

The following tutorial column from laravel will introduce to you how Laravel's $this->app and app() come from. I hope it will be helpful to friends who need it!

Breakpoint debugging looks for the corresponding file, ignores the minor steps, and only describes the core actions. '/' indicates the directory where index.php is located.

Address: index.php

$app = require_once __DIR__.'/../bootstrap/app.php';

$app initialization

Path/…/bootstrap/app.php

$app = new Illuminate\Foundation\Application(
    realpath(__DIR__.'/../')
);//$app初始化工作

$app initialization class and constructor

class Application extends Container implements ApplicationContract,HttpKernelInterface
{
    //继承Container类，Container类实现应用契约接口与请求接口
    public function __construct($basePath = null){
       if ($basePath) {//$basePath = '/../'
           $this->setBasePath($basePath);//路径绑定
       }
       $this->registerBaseBindings();//基础绑定
       $this->registerBaseServiceProviders();//注册基础服务提供者
       $this->registerCoreContainerAliases();//注册别名
    }
}

Path binding

Application的setBasePath(’/…/’)方法调用Container的instance(a b s t r a c t , abstract,abstract,instance)方法赋值Contaienr类instances
instances: array:9 [▼
“path” => “\var\www\app”
“path.base” => “\var\www”
“path.lang” => “\var\www\resources\lang”
“path.config” => “\var\www\config”
“path.public” => “\var\www\public”
“path.storage” => “\var\www\storage”
“path.database” => “\var\www\database”
“path.resources” => “\var\www\resources”
“path.bootstrap” => “\var\www\bootstrap”
]

Basic binding

Add binding to Container instances

    "app" => Application {#2}
      "Illuminate\Container\Container" => Application {#2}
      "Illuminate\Foundation\PackageManifest" => PackageManifest {#4 ▼
            +files: Filesystem {#5}
            +basePath: "\var\www"
            +vendorPath: "\var\www\vendor"
            +manifestPath: "\var\www\bootstrap\cache\packages.php"
            +manifest: null
        }

app and Container point to the current instance

PackageMainfest is a package management instance. In the construction method, files register a file system instance.

Register a basic service provider.

//class Application
protected function registerBaseServiceProviders()
{
    $this->register(new EventServiceProvider($this));
    $this->register(new LogServiceProvider($this));
    $this->register(new RoutingServiceProvider($this));
}

Event, Log, and Routing basic services inherit ServiceProvider and will be initialized during initialization. app attribute assignment Application instance

//class ServiceProvider    
public function __construct($app)
{
    $this->app = $app;
}

Execute the Application class register method

//Application
public function register($provider, $options = [], $force = false)
{
    if (is_string($provider)) {
        $provider = $this->resolveProvider($provider);
    }
    if (method_exists($provider, 'register')) {
        $provider->register();//赋值bindings
    }
    //将服务提供者添加到serviceProviders属性队列
    //将服务提供者类名添加到loaderProviders属性
    $this->markAsRegistered($provider);
    return $provider;
}

Provides two methods for provider registration;

One is a direct instance of the string class name,

One is to execute the $$provider->register() method to register,

Currently execute the second method,

Look back at the register method of the current EventServiceProvider instance

public function register()
{
    $this->app->singleton('events', function ($app) {
        return (new Dispatcher($app))->setQueueResolver(function () use ($app) {
            return $app->make(QueueFactoryContract::class);
        });
    });
}

Call the singleton method of the Application instance

//class Continer
public function singleton($abstract, $concrete = null)
{
    $this->bind($abstract, $concrete, true);
}

Call the bind method and assign bindings

//class Container
public function bind($abstract, $concrete = null, $shared = false)
{
    if (is_null($concrete)) {
        $concrete = $abstract;
    }
    if (! $concrete instanceof Closure) {
        $concrete = $this->getClosure($abstract, $concrete);
    }
    $this->bindings[$abstract] = compact('concrete', 'shared');
}

Go back to the Application class register method and execute markAsRegistered($provider)

//class Application
protected function markAsRegistered($provider)
{
    $this->serviceProviders[] = $provider;
    $this->loadedProviders[get_class($provider)] = true;
}

LogServerProvider and RoutingServiceProvider are similar

Alias ​​binding

//class Application
public function registerCoreContainerAliases()
{
    foreach ([
        'app'                  => [self::class, \Illuminate\Contracts\Container\Container::class, \Illuminate\Contracts\Foundation\Application::class,  \Psr\Container\ContainerInterface::class],
        'auth'                 => [\Illuminate\Auth\AuthManager::class, \Illuminate\Contracts\Auth\Factory::class],
        'auth.driver'          => [\Illuminate\Contracts\Auth\Guard::class],
        'blade.compiler'       => [\Illuminate\View\Compilers\BladeCompiler::class],
        'cache'                => [\Illuminate\Cache\CacheManager::class, \Illuminate\Contracts\Cache\Factory::class],
        'cache.store'          => [\Illuminate\Cache\Repository::class, \Illuminate\Contracts\Cache\Repository::class],
        'config'               => [\Illuminate\Config\Repository::class, \Illuminate\Contracts\Config\Repository::class],
        'cookie'               => [\Illuminate\Cookie\CookieJar::class, \Illuminate\Contracts\Cookie\Factory::class, \Illuminate\Contracts\Cookie\QueueingFactory::class],
        'encrypter'            => [\Illuminate\Encryption\Encrypter::class, \Illuminate\Contracts\Encryption\Encrypter::class],
        'db'                   => [\Illuminate\Database\DatabaseManager::class],
        'db.connection'        => [\Illuminate\Database\Connection::class, \Illuminate\Database\ConnectionInterface::class],
        'events'               => [\Illuminate\Events\Dispatcher::class, \Illuminate\Contracts\Events\Dispatcher::class],
        'files'                => [\Illuminate\Filesystem\Filesystem::class],
        'filesystem'           => [\Illuminate\Filesystem\FilesystemManager::class, \Illuminate\Contracts\Filesystem\Factory::class],
        'filesystem.disk'      => [\Illuminate\Contracts\Filesystem\Filesystem::class],
        'filesystem.cloud'     => [\Illuminate\Contracts\Filesystem\Cloud::class],
        'hash'                 => [\Illuminate\Contracts\Hashing\Hasher::class],
        'translator'           => [\Illuminate\Translation\Translator::class, \Illuminate\Contracts\Translation\Translator::class],
        'log'                  => [\Illuminate\Log\Writer::class, \Illuminate\Contracts\Logging\Log::class, \Psr\Log\LoggerInterface::class],
        'mailer'               => [\Illuminate\Mail\Mailer::class, \Illuminate\Contracts\Mail\Mailer::class, \Illuminate\Contracts\Mail\MailQueue::class],
        'auth.password'        => [\Illuminate\Auth\Passwords\PasswordBrokerManager::class, \Illuminate\Contracts\Auth\PasswordBrokerFactory::class],
        'auth.password.broker' => [\Illuminate\Auth\Passwords\PasswordBroker::class, \Illuminate\Contracts\Auth\PasswordBroker::class],
        'queue'                => [\Illuminate\Queue\QueueManager::class, \Illuminate\Contracts\Queue\Factory::class, \Illuminate\Contracts\Queue\Monitor::class],
        'queue.connection'     => [\Illuminate\Contracts\Queue\Queue::class],
        'queue.failer'         => [\Illuminate\Queue\Failed\FailedJobProviderInterface::class],
        'redirect'             => [\Illuminate\Routing\Redirector::class],
        'redis'                => [\Illuminate\Redis\RedisManager::class, \Illuminate\Contracts\Redis\Factory::class],
        'request'              => [\Illuminate\Http\Request::class, \Symfony\Component\HttpFoundation\Request::class],
        'router'               => [\Illuminate\Routing\Router::class, \Illuminate\Contracts\Routing\Registrar::class, \Illuminate\Contracts\Routing\BindingRegistrar::class],
        'session'              => [\Illuminate\Session\SessionManager::class],
        'session.store'        => [\Illuminate\Session\Store::class, \Illuminate\Contracts\Session\Session::class],
        'url'                  => [\Illuminate\Routing\UrlGenerator::class, \Illuminate\Contracts\Routing\UrlGenerator::class],
        'validator'            => [\Illuminate\Validation\Factory::class, \Illuminate\Contracts\Validation\Factory::class],
        'view'                 => [\Illuminate\View\Factory::class, \Illuminate\Contracts\View\Factory::class],
    ] as $key => $aliases) {
        foreach ($aliases as $alias) {
            $this->alias($key, $alias);
        }
    }
}

Assign a value to the alias attribute

$app core class binding

/…/bootstrap/app.php
/**
 *核心类绑定
 */
$app->singleton(
    Illuminate\Contracts\Http\Kernel::class,
    App\Http\Kernel::class
);
$app->singleton(
    Illuminate\Contracts\Console\Kernel::class,
    App\Console\Kernel::class
);
$app->singleton(
    Illuminate\Contracts\Debug\ExceptionHandler::class,
    App\Exceptions\Handler::class
);

Call the bind function

//class Container
public function singleton($abstract, $concrete = null)
{
    $this->bind($abstract, $concrete, true);
}

Bind the default callback function to the string class name

//class Container
public function bind($abstract, $concrete = null, $shared = false)
{
    // If the factory is not a Closure, it means it is just a class name which is
    // bound into this container to the abstract type and we will just wrap it
    // up inside its own Closure to give us more convenience when extending.
    if (! $concrete instanceof Closure) {
        $concrete = $this->getClosure($abstract, $concrete);
    }
    $this->bindings[$abstract] = compact('concrete', 'shared');
}

getClosure returns the default callback function

//class Container
protected function getClosure($abstract, $concrete)
{
    return function ($container, $parameters = []) use ($abstract, $concrete) {
        if ($abstract == $concrete) {
            return $container->build($concrete);
        }
        return $container->make($concrete, $parameters);
    };
}

Finally: return $app

/…/bootstrap/app.php
return $app;

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