<?php namespace Illuminate\Foundation\Http;
use Exception;
use Illuminate\Routing\Router;
use Illuminate\Pipeline\Pipeline;
use Illuminate\Support\Facades\Facade;
use Illuminate\Contracts\Foundation\Application;
use Illuminate\Contracts\Routing\TerminableMiddleware;
use Illuminate\Contracts\Http\Kernel as KernelContract;
class Kernel implements KernelContract {
/**
* The application implementation.
*
* @var \Illuminate\Contracts\Foundation\Application
*/
protected $app;
/**
* The router instance.
*
* @var \Illuminate\Routing\Router
*/
protected $router;
/**
* The bootstrap classes for the application.
* 应用程序启动时需要引导的类。
*
* @var array
*/
protected $bootstrappers = [
// 检测运行环境，载入对应的 `.env` 文件
'Illuminate\Foundation\Bootstrap\DetectEnvironment',
// 载入配置项，设置时区、编码
'Illuminate\Foundation\Bootstrap\LoadConfiguration',
// 读取 app.log 配置，调用对应的的日志处理方法，绑定日志处理实例为 Monolog
'Illuminate\Foundation\Bootstrap\ConfigureLogging',
// 设置“错误”“异常”“shutdown”处理函数，控制错误输出
'Illuminate\Foundation\Bootstrap\HandleExceptions',
// 为 Facade 设置应用程序实例，注册别名自动加载
'Illuminate\Foundation\Bootstrap\RegisterFacades',
// 注册 providers 配置项中的所有服务提供者
'Illuminate\Foundation\Bootstrap\RegisterProviders',
// 启动应用程序的服务提供者
'Illuminate\Foundation\Bootstrap\BootProviders',
];
/**
* The application's middleware stack.
*
* @var array
*/
protected $middleware = [];
/**
* The application's route middleware.
*
* @var array
*/
protected $routeMiddleware = [];
/**
* 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 = $router;
foreach ($this->routeMiddleware as $key => $middleware)
{
$router->middleware($key, $middleware);
}
}
/**
* Handle an incoming HTTP request.
* 处理传入的 HTTP 请求。
*
* @param \Illuminate\Http\Request $request 请求实例
* @return \Illuminate\Http\Response
*/
public function handle($request)
{
try
{
// 通过中间件或路由发送给定的请求
$response = $this->sendRequestThroughRouter($request);
}
catch (Exception $e)
{
$this->reportException($e);
$response = $this->renderException($request, $e);
}
// 触发 kernel.handled 事件，参数 $request, $response
$this->app['events']->fire('kernel.handled', [$request, $response]);
return $response;
}
/**
* Send the given request through the middleware / router.
* 通过中间件或路由发送给定的请求。
*
* @param \Illuminate\Http\Request $request
* @return \Illuminate\Http\Response
*/
protected function sendRequestThroughRouter($request)
{
// 在容器中注册共享实例
$this->app->instance('request', $request);
// 清除一个已经解析的 facade 实例
Facade::clearResolvedInstance('request');
// 通过 HTTP 请求引导应用程序
// 运行各引导类，调用其 bootstrap 方法，并触发“bootstrapping: Xxx”和“bootstrapped: Xxx”事件
$this->bootstrap();
// 获取响应实例
// 调用 router.before 路由前置过滤器，参数 $request
// 若路由前置过滤器没有返回响应实例，则从一个路由调度请求，并取得响应实例
// 调用 router.after 路由后置过滤器，参数 $request, $response
return (new Pipeline($this->app))
->send($request)
->through($this->middleware)
->then($this->dispatchToRouter());
}
/**
* Call the terminate method on any terminable middleware.
* 在所有需要结束的中间件中调用 terminate 方法。
*
* @param \Illuminate\Http\Request $request
* @param \Illuminate\Http\Response $response
* @return void
*/
public function terminate($request, $response)
{
$routeMiddlewares = $this->gatherRouteMiddlewares($request);
foreach (array_merge($routeMiddlewares, $this->middleware) as $middleware)
{
$instance = $this->app->make($middleware);
if ($instance instanceof TerminableMiddleware)
{
$instance->terminate($request, $response);
}
}
$this->app->terminate();
}
/**
* Gather the route middleware for the given request.
*
* @param \Illuminate\Http\Request $request
* @return array
*/
protected function gatherRouteMiddlewares($request)
{
if ($request->route())
{
return $this->router->gatherRouteMiddlewares($request->route());
}
return [];
}
/**
* Add a new middleware to beginning of the stack if it does not already exist.
*
* @param string $middleware
* @return $this
*/
public function prependMiddleware($middleware)
{
if (array_search($middleware, $this->middleware) === false)
{
array_unshift($this->middleware, $middleware);
}
return $this;
}
/**
* Add a new middleware to end of the stack if it does not already exist.
*
* @param string $middleware
* @return $this
*/
public function pushMiddleware($middleware)
{
if (array_search($middleware, $this->middleware) === false)
{
$this->middleware[] = $middleware;
}
return $this;
}
/**
* Bootstrap the application for HTTP requests.
* 通过 HTTP 请求引导应用程序。
*
* @return void
*/
public function bootstrap()
{
// 若应用程序未被引导
if ( ! $this->app->hasBeenBootstrapped())
{
// 运行各引导类，调用其 bootstrap 方法，并触发“bootstrapping: Xxx”和“bootstrapped: Xxx”事件
$this->app->bootstrapWith($this->bootstrappers());
}
}
/**
* Get the route dispatcher callback.
* 获取路由回调。
*
* @return \Closure
*/
protected function dispatchToRouter()
{
return function($request)
{
$this->app->instance('request', $request);
return $this->router->dispatch($request);
};
}
/**
* Get the bootstrap classes for the application.
* 从应用程序中获取引导类。
*
* @return array
*/
protected function bootstrappers()
{
return $this->bootstrappers;
}
/**
* Report the exception to the exception handler.
*
* @param \Exception $e
* @return void
*/
protected function reportException(Exception $e)
{
$this->app['Illuminate\Contracts\Debug\ExceptionHandler']->report($e);
}
/**
* Render the exception to a response.
*
* @param \Illuminate\Http\Request $request
* @param \Exception $e
* @return \Symfony\Component\HttpFoundation\Response
*/
protected function renderException($request, Exception $e)
{
return $this->app['Illuminate\Contracts\Debug\ExceptionHandler']->render($request, $e);
}
/**
* Get the Laravel application instance.
*
* @return \Illuminate\Contracts\Foundation\Application
*/
public function getApplication()
{
return $this->app;
}
}