你知道Laravel的$this->app以及app()是怎么来的吗？

下面给大家介绍Laravel的$this->app以及app()是怎么来的，希望对需要的朋友有所帮助！

断点调试寻找对应文件，忽略次要步骤，仅描述核心动作，‘/’表示index.php所在目录

地址:index.php

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

$app初始化

路径/…/bootstrap/app.php

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

$app初始化的类及构造函数

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
    }
}

路径绑定

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"
]

基础绑定

向Container的instances中添加绑定

"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与Container指向当前实例

PackageMainfest 为包管理实例，构造方法中files注册文件系统实例

注册基础服务提供者

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

Event、Log、Routing基础服务继承ServiceProvider，初始化的时候将app属性赋值Application实例

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

执行Application类register方法

//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;
}

为provider注册提供了两种方法；

一种是字符串类名直接实例，

一种是执行$$provider->register()方法注册，

当前执行第二种方法，

回看当前EventServiceProvider实例的register方法

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

调用Application实例的singleton方法

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

调用bind方法，赋值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');
}

回到Application类register方法中并执行markAsRegistered($provider)

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

LogServerProvider、RoutingServiceProvider与之类似

别名绑定

//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);
        }
    }
}

为alias属性赋值

$app核心类绑定

/…/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
);

调用bind函数

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

对字符串类名进行默认回调函数绑定

//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返回默认回调函数

//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);
    };
}

最终：返回$app

/…/bootstrap/app.php
return $app;