Laravel的生命周期

Posted 2021-06-20 willem_chen

Laravel的生命周期

laravel/public/index.php

/**
 * laravel的启动时间
 */
define('LARAVEL_START', microtime(true));

/**
 * 加载项目依赖。
 * 现代PHP依赖于Composer包管理器，入口文件通过引入由Composer包管理器。
 * 自动生成的类加载程序，可以轻松注册并加载所依赖的第三方组件库。
 */
require __DIR__.'/../vendor/autoload.php';

/**
 * 创建laravel应用实例。
 */
$app = require_once __DIR__.'/../bootstrap/app.php';

// 接受请求并响应
$kernel = $app->make(Illuminate\\Contracts\\Http\\Kernel::class);

$response = $kernel->handle(
    $request = Illuminate\\Http\\Request::capture()
);

// 结束请求，进行回调
$response->send();

// 终止程序
$kernel->terminate($request, $response);

laravel/boostrap/app.php

# 第一部分：创建应用实例
$app = new Illuminate\\Foundation\\Application(
    realpath(__DIR__.'/../')
);

# 第二部分：完成内核绑定
$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
);

return $app;

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

class Kernel implements KernelContract
{
    protected $bootstrappers = [
        \\Illuminate\\Foundation\\Bootstrap\\LoadEnvironmentVariables::class, // 注册系统环境配置
        \\Illuminate\\Foundation\\Bootstrap\\LoadConfiguration::class,              // 注册系统配置 
        \\Illuminate\\Foundation\\Bootstrap\\HandleExceptions::class,              // 注册异常注册
        \\Illuminate\\Foundation\\Bootstrap\\RegisterFacades::class,                // 注册门面模式
        \\Illuminate\\Foundation\\Bootstrap\\RegisterProviders::class,              // 注册服务提供者 
        \\Illuminate\\Foundation\\Bootstrap\\BootProviders::class,                    // 注册服务提供者boot
    ];

    // 处理请求
    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;
    }

    protected function sendRequestThroughRouter($request)
    {
        # 一、将$request实例注册到APP容器
        $this->app->instance('request', $request);

        # 二、清除之前的$request实例缓存
        Facade::clearResolvedInstance('request');

        # 三、启动引导程序
        $this->bootstrap();

        # 四、发送请求
        return (new Pipeline($this->app)) //创建管道
                    ->send($request)      //发送请求
                    ->through($this->app->shouldSkipMiddleware() ? [] : $this->middleware)  //通过中间件
                    ->then($this->dispatchToRouter());  //分发到路由
    }

    # 启动引导程序
    public function bootstrap()
    {
        if (! $this->app->hasBeenBootstrapped()) {
            $this->app->bootstrapWith($this->bootstrappers());
        }
    }
    
    # 路由分发
    protected function dispatchToRouter()
    {
        return function ($request) {
            $this->app->instance('request', $request);

            return $this->router->dispatch($request);
        };
    }

    #  终止程序
    public function terminate($request, $response)
    {
        $this->terminateMiddleware($request, $response);

        $this->app->terminate();
    }