02. HTTP Kernel Handle 解析

[xiaohuilam]

Kernel Handle

App\Http\Kernel 继承自 Illuminate\Foundation\Http\Kernel 类，所以本文章的分析主要集中在 app/Http/Kernel.php 和 vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php 两个类中

__construct 解析

因为 App\Http\Kernel 没有 __construct 方法，所以穿透到了 Illuminate\Foundation\Http\Kernel 的 __construct：

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 82 to 103 in d081c91

	/**
	* Create a new HTTP kernel instance.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @param \Illuminate\Routing\Router $router
	* @return void
	*/
	public function __construct(Application $app, Router $router)
	{
	$this->app = $app;
	$this->router = $router;
	$router->middlewarePriority = $this->middlewarePriority;
	foreach ($this->middlewareGroups as $key => $middleware) {
	$router->middlewareGroup($key, $middleware);
	}
	foreach ($this->routeMiddleware as $key => $middleware) {
	$router->aliasMiddleware($key, $middleware);
	}
	}

首先是此方法传入参数的 __construct(Application $app, Router $router) 声明，这里恰好使用了 Laravel 容器的依赖注入(Dependency Injection，Inversion of Control的一种)设计。具体的在本篇不讲述，可参见本篇末尾的单独分析的链接的文章。

执行到 __construct 时， Illuminate\Foundation\Application 容器会将 Illuminate\Foundation\Application（即应用容器自身）和 Illuminate\Routing\Router 注入到方法内。然后逻辑代码将两个对象赋给 App\Http\Kernel 的 $this 属性中。

然后将 Illuminate\Foundation\Http\Kernel 的 $middlewarePriority 属性

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 66 to 80 in d081c91

	/**
	* The priority-sorted list of middleware.
	*
	* Forces the listed middleware to always be in the given order.
	*
	* @var array
	*/
	protected $middlewarePriority = [
	\Illuminate\Session\Middleware\StartSession::class,
	\Illuminate\View\Middleware\ShareErrorsFromSession::class,
	\Illuminate\Auth\Middleware\Authenticate::class,
	\Illuminate\Session\Middleware\AuthenticateSession::class,
	\Illuminate\Routing\Middleware\SubstituteBindings::class,
	\Illuminate\Auth\Middleware\Authorize::class,
	];

赋值给 Illuminate\Routing\Router 的 $middlewarePriority 属性

根据其注释，此属性是强制对 middleward 中间件执行顺序进行排序的作用。

在后面将 App\Http\Kernel 中声明的 $middlewareGroup

laravel/app/Http/Kernel.php

Lines 24 to 44 in d081c91

	/**
	* The application's route middleware groups.
	*
	* @var array
	*/
	protected $middlewareGroups = [
	'web' => [
	\App\Http\Middleware\EncryptCookies::class,
	\Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse::class,
	\Illuminate\Session\Middleware\StartSession::class,
	// \Illuminate\Session\Middleware\AuthenticateSession::class,
	\Illuminate\View\Middleware\ShareErrorsFromSession::class,
	\App\Http\Middleware\VerifyCsrfToken::class,
	\Illuminate\Routing\Middleware\SubstituteBindings::class,
	],
	'api' => [
	'throttle:60,1',
	'bindings',
	],
	];

在 Illuminate\Foundation\Http\Kernel 的 96-98行，调用 Illuminate\Routing\Router 的 middlewareGroup 方法，存到 $router 的 $middlewareGroup 中

laravel/vendor/laravel/framework/src/Illuminate/Routing/Router.php

Lines 854 to 866 in d081c91

	/**
	* Register a group of middleware.
	*
	* @param string $name
	* @param array $middleware
	* @return $this
	*/
	public function middlewareGroup($name, array $middleware)
	{
	$this->middlewareGroups[$name] = $middleware;
	return $this;
	}

紧接着，将

laravel/app/Http/Kernel.php

Lines 46 to 63 in d081c91

	/**
	* The application's route middleware.
	*
	* These middleware may be assigned to groups or used individually.
	*
	* @var array
	*/
	protected $routeMiddleware = [
	'auth' => \App\Http\Middleware\Authenticate::class,
	'auth.basic' => \Illuminate\Auth\Middleware\AuthenticateWithBasicAuth::class,
	'bindings' => \Illuminate\Routing\Middleware\SubstituteBindings::class,
	'cache.headers' => \Illuminate\Http\Middleware\SetCacheHeaders::class,
	'can' => \Illuminate\Auth\Middleware\Authorize::class,
	'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class,
	'signed' => \Illuminate\Routing\Middleware\ValidateSignature::class,
	'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class,
	'verified' => \Illuminate\Auth\Middleware\EnsureEmailIsVerified::class,
	];

的中间件，调用 Illuminate\Routing\Router 的 aliasMiddleware 的方法，绑定到 $router 的 $middleware 中

laravel/vendor/laravel/framework/src/Illuminate/Routing/Router.php

Lines 819 to 831 in d081c91

	/**
	* Register a short-hand name for a middleware.
	*
	* @param string $name
	* @param string $class
	* @return $this
	*/
	public function aliasMiddleware($name, $class)
	{
	$this->middleware[$name] = $class;
	return $this;
	}

至此， Kernel::__construct() 解析完毕。

handle 解析

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 105 to 132 in d081c91

	/**
	* Handle an incoming HTTP request.
	*
	* @param \Illuminate\Http\Request $request
	* @return \Illuminate\Http\Response
	*/
	public function handle($request)
	{
	try {
	$request->enableHttpMethodParameterOverride();
	$response = $this->sendRequestThroughRouter($request);
	} catch (Exception $e) {
	$this->reportException($e);
	$response = $this->renderException($request, $e);
	} catch (Throwable $e) {
	$this->reportException($e = new FatalThrowableError($e));
	$response = $this->renderException($request, $e);
	}
	$this->app['events']->dispatch(
	new Events\RequestHandled($request, $response)
	);
	return $response;
	}

调用到 Symfony\Component\HttpFoundation\Request 的 enableHttpMethodParameterOverride 方法

Illuminate\Http\Request 继承自 Symfony\Component\HttpFoundation\Request
并且 Illuminate\Http\Request 未覆盖 enableHttpMethodParameterOverride

laravel/vendor/symfony/http-foundation/Request.php

Lines 638 to 652 in d081c91

	/**
	* Enables support for the _method request parameter to determine the intended HTTP method.
	*
	* Be warned that enabling this feature might lead to CSRF issues in your code.
	* Check that you are using CSRF tokens when required.
	* If the HTTP method parameter override is enabled, an html-form with method "POST" can be altered
	* and used to send a "PUT" or "DELETE" request via the _method request parameter.
	* If these methods are not protected against CSRF, this presents a possible vulnerability.
	*
	* The HTTP method can only be overridden when the real HTTP method is POST.
	*/
	public static function enableHttpMethodParameterOverride()
	{
	self::$httpMethodParameterOverride = true;
	}

然后，调用 Illuminate\Foundation\Http\Kernel 的 sendRequestThroughRouter

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 134 to 152 in d081c91

	/**
	* Send the given request through the middleware / router.
	*
	* @param \Illuminate\Http\Request $request
	* @return \Illuminate\Http\Response
	*/
	protected function sendRequestThroughRouter($request)
	{
	$this->app->instance('request', $request);
	Facade::clearResolvedInstance('request');
	$this->bootstrap();
	return (new Pipeline($this->app))
	->send($request)
	->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)
	->then($this->dispatchToRouter());
	}

通过第142行，将 $request 注入进 Illuminate\Foundation\Application 容器。

144行，将门面类中的 request 数据清理掉

laravel/vendor/laravel/framework/src/Illuminate/Support/Facades/Facade.php

Lines 164 to 173 in d081c91

	/**
	* Clear a resolved facade instance.
	*
	* @param string $name
	* @return void
	*/
	public static function clearResolvedInstance($name)
	{
	unset(static::$resolvedInstance[$name]);
	}

Bootstrap 解析

然后146行，调用 Illuminate\Foundation\Http\Kernel 的 bootstrap 方法

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 154 to 164 in d081c91

	/**
	* Bootstrap the application for HTTP requests.
	*
	* @return void
	*/
	public function bootstrap()
	{
	if (! $this->app->hasBeenBootstrapped()) {
	$this->app->bootstrapWith($this->bootstrappers());
	}
	}

第161执行到容器的 hasBeenBootstrapped 方法

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Application.php

Lines 249 to 257 in d081c91

	/**
	* Determine if the application has been bootstrapped before.
	*
	* @return bool
	*/
	public function hasBeenBootstrapped()
	{
	return $this->hasBeenBootstrapped;
	}

第162实际得到这个数组

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 31 to 43 in d081c91

	/**
	* The bootstrap classes for the application.
	*
	* @var array
	*/
	protected $bootstrappers = [
	\Illuminate\Foundation\Bootstrap\LoadEnvironmentVariables::class,
	\Illuminate\Foundation\Bootstrap\LoadConfiguration::class,
	\Illuminate\Foundation\Bootstrap\HandleExceptions::class,
	\Illuminate\Foundation\Bootstrap\RegisterFacades::class,
	\Illuminate\Foundation\Bootstrap\RegisterProviders::class,
	\Illuminate\Foundation\Bootstrap\BootProviders::class,
	];

然后将数组做为参数，执行容器的 bootstrapWith 方法

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Application.php

Lines 193 to 210 in d081c91

	/**
	* Run the given array of bootstrap classes.
	*
	* @param array $bootstrappers
	* @return void
	*/
	public function bootstrapWith(array $bootstrappers)
	{
	$this->hasBeenBootstrapped = true;
	foreach ($bootstrappers as $bootstrapper) {
	$this['events']->fire('bootstrapping: '.$bootstrapper, [$this]);
	$this->make($bootstrapper)->bootstrap($this);
	$this['events']->fire('bootstrapped: '.$bootstrapper, [$this]);
	}
	}

特别留意206行的 make 调用

关于容器 make 方法的细节
请查阅 10. 容器的 singleton 和 bind 的实现 的 “揭开 Container::make() 神秘的面纱” 段落

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Application.php

Lines 716 to 734 in d081c91

	/**
	* Resolve the given type from the container.
	*
	* (Overriding Container::make)
	*
	* @param string $abstract
	* @param array $parameters
	* @return mixed
	*/
	public function make($abstract, array $parameters = [])
	{
	$abstract = $this->getAlias($abstract);
	if (isset($this->deferredServices[$abstract]) && ! isset($this->instances[$abstract])) {
	$this->loadDeferredProvider($abstract);
	}
	return parent::make($abstract, $parameters);
	}

关于 loadDeferredProvider 的逻辑会最终执行到

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Application.php

Lines 691 to 714 in d081c91

	/**
	* Register a deferred provider and service.
	*
	* @param string $provider
	* @param string|null $service
	* @return void
	*/
	public function registerDeferredProvider($provider, $service = null)
	{
	// Once the provider that provides the deferred service has been registered we
	// will remove it from our local list of the deferred services with related
	// providers so that this container does not try to resolve it out again.
	if ($service) {
	unset($this->deferredServices[$service]);
	}
	$this->register($instance = new $provider($this));
	if (! $this->booted) {
	$this->booting(function () use ($instance) {
	$this->bootProvider($instance);
	});
	}
	}

第710行的 booting 方法，是登记一个闭包 (并不会马上执行这个闭包)， 然后这个服务提供者在 boot() 阶段的 $this->fireAppCallbacks($this->bootingCallbacks) 才会真正被创建。 关联阅读请见 04. ServiceProvider Boot 解析

然后结果就是依次执行

• \Illuminate\Foundation\Bootstrap\LoadEnvironmentVariables
• \Illuminate\Foundation\Bootstrap\LoadConfiguration
• \Illuminate\Foundation\Bootstrap\HandleExceptions
• \Illuminate\Foundation\Bootstrap\RegisterFacades
• \Illuminate\Foundation\Bootstrap\RegisterProviders
• \Illuminate\Foundation\Bootstrap\BootProviders

这些 Bootstrap 类的 bootstrap 方法

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadEnvironmentVariables.php

Lines 13 to 35 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	public function bootstrap(Application $app)
	{
	if ($app->configurationIsCached()) {
	return;
	}
	$this->checkForSpecificEnvironmentFile($app);
	try {
	(new Dotenv($app->environmentPath(), $app->environmentFile()))->load();
	} catch (InvalidPathException $e) {
	//
	} catch (InvalidFileException $e) {
	echo 'The environment file is invalid: '.$e->getMessage();
	die(1);
	}
	}

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/LoadConfiguration.php

Lines 14 to 52 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	public function bootstrap(Application $app)
	{
	$items = [];
	// First we will see if we have a cache configuration file. If we do, we'll load
	// the configuration items from that file so that it is very quick. Otherwise
	// we will need to spin through every configuration file and load them all.
	if (file_exists($cached = $app->getCachedConfigPath())) {
	$items = require $cached;
	$loadedFromCache = true;
	}
	// Next we will spin through all of the configuration files in the configuration
	// directory and load each one into the repository. This will make all of the
	// options available to the developer for use in various parts of this app.
	$app->instance('config', $config = new Repository($items));
	if (! isset($loadedFromCache)) {
	$this->loadConfigurationFiles($app, $config);
	}
	// Finally, we will set the application's environment based on the configuration
	// values that were loaded. We will pass a callback which will be used to get
	// the environment in a web context where an "--env" switch is not present.
	$app->detectEnvironment(function () use ($config) {
	return $config->get('app.env', 'production');
	});
	date_default_timezone_set($config->get('app.timezone', 'UTC'));
	mb_internal_encoding('UTF-8');
	}

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/HandleExceptions.php

Lines 22 to 43 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	public function bootstrap(Application $app)
	{
	$this->app = $app;
	error_reporting(-1);
	set_error_handler([$this, 'handleError']);
	set_exception_handler([$this, 'handleException']);
	register_shutdown_function([$this, 'handleShutdown']);
	if (! $app->environment('testing')) {
	ini_set('display_errors', 'Off');
	}
	}

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/RegisterFacades.php

Lines 12 to 28 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	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();
	}

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/RegisterProviders.php

Lines 9 to 18 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	public function bootstrap(Application $app)
	{
	$app->registerConfiguredProviders();
	}

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Bootstrap/BootProviders.php

Lines 9 to 18 in d081c91

	/**
	* Bootstrap the given application.
	*
	* @param \Illuminate\Contracts\Foundation\Application $app
	* @return void
	*/
	public function bootstrap(Application $app)
	{
	$app->boot();
	}

上面列出的清单中，分别作用为

类	作用
\Illuminate\Foundation\Bootstrap\LoadEnvironmentVariables	加载环境变量
\Illuminate\Foundation\Bootstrap\LoadConfiguration	加载config
\Illuminate\Foundation\Bootstrap\HandleExceptions	错误处理者
\Illuminate\Foundation\Bootstrap\RegisterFacades	注册门面类
\Illuminate\Foundation\Bootstrap\RegisterProviders	注册服务提供者
\Illuminate\Foundation\Bootstrap\BootProviders	启动服务提供者

其中最后两项在 laravel 请求的生命周期中是至关重要的，我们将在后续文章中重点讲解。

在 bootstrap 阶段结束后，Kernel::sendRequestThroughRouter 后面带 pipeline 关键字的代码就是管道。

关于管道请查阅 05. Pipeline 解析

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 148 to 151 in d081c91

	return (new Pipeline($this->app))
	->send($request)
	->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)
	->then($this->dispatchToRouter());

在进入管道前， 调用了 dispatchToRouter 返回一个闭包对象

laravel/vendor/laravel/framework/src/Illuminate/Foundation/Http/Kernel.php

Lines 166 to 178 in d081c91

	/**
	* Get the route dispatcher callback.
	*
	* @return \Closure
	*/
	protected function dispatchToRouter()
	{
	return function ($request) {
	$this->app->instance('request', $request);
	return $this->router->dispatch($request);
	};
	}

匹配路由的逻辑清晰可见

laravel/vendor/laravel/framework/src/Illuminate/Routing/Router.php

Lines 601 to 682 in d081c91

	/**
	* Dispatch the request to the application.
	*
	* @param \Illuminate\Http\Request $request
	* @return \Illuminate\Http\Response|\Illuminate\Http\JsonResponse
	*/
	public function dispatch(Request $request)
	{
	$this->currentRequest = $request;
	return $this->dispatchToRoute($request);
	}
	/**
	* Dispatch the request to a route and return the response.
	*
	* @param \Illuminate\Http\Request $request
	* @return mixed
	*/
	public function dispatchToRoute(Request $request)
	{
	return $this->runRoute($request, $this->findRoute($request));
	}
	/**
	* Find the route matching a given request.
	*
	* @param \Illuminate\Http\Request $request
	* @return \Illuminate\Routing\Route
	*/
	protected function findRoute($request)
	{
	$this->current = $route = $this->routes->match($request);
	$this->container->instance(Route::class, $route);
	return $route;
	}
	/**
	* Return the response for the given route.
	*
	* @param \Illuminate\Http\Request $request
	* @param \Illuminate\Routing\Route $route
	* @return mixed
	*/
	protected function runRoute(Request $request, Route $route)
	{
	$request->setRouteResolver(function () use ($route) {
	return $route;
	});
	$this->events->dispatch(new Events\RouteMatched($route, $request));
	return $this->prepareResponse($request,
	$this->runRouteWithinStack($route, $request)
	);
	}
	/**
	* Run the given route within a Stack "onion" instance.
	*
	* @param \Illuminate\Routing\Route $route
	* @param \Illuminate\Http\Request $request
	* @return mixed
	*/
	protected function runRouteWithinStack(Route $route, Request $request)
	{
	$shouldSkipMiddleware = $this->container->bound('middleware.disable') &&
	$this->container->make('middleware.disable') === true;
	$middleware = $shouldSkipMiddleware ? [] : $this->gatherRouteMiddleware($route);
	return (new Pipeline($this->container))
	->send($request)
	->through($middleware)
	->then(function ($request) use ($route) {
	return $this->prepareResponse(
	$request, $route->run()
	);
	});
	}

如果一路抽丝剥茧，我们便能找到 Router 调用 controller 的逻辑了。 请见06. RouteServiceProvider 详解 最后段落。