laravel框架启动过程

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一篇让读者对laravel框架启动过程有清晰了解的文章

阅读本文前，建议先阅读laravel生命周期

核心文件

了解laravel的读者都知道，public目录是laravel项目的入口，所以，laravel框架的整个启动流程就定义在public/index.php文件中。

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define('LARAVEL_START', microtime(true));

// 注册自动加载器
require __DIR__.'/../vendor/autoload.php';

// 实例化应用
$app = require_once __DIR__.'/../bootstrap/app.php';

// 处理请求和响应
$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

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

$response->send();

$kernel->terminate($request, $response);

上面短短几行代码是如何将laravel框架运行起来的呢？请看下面具体分析

注册自动加载器

启动一个框架，自然少不了在文件中加载大量的类，而laravel实现类的加载是十分轻松的！

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// 记录项目启动的时刻
define('LARAVEL_START', microtime(true));

// 注册类自动加载器
require __DIR__.'/../vendor/autoload.php';

autoload.php是由composer提供的类自动加载器文件，包含它即可以实现自动加载框架类。

实例化应用

包含了类文件后，接下来，就是实例化laravel应用。

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$app = require_once __DIR__.'/../bootstrap/app.php';
``` 
通过上述一条语句实现了laravel application的实例化，下面分析下`$app`实例化的具体过程：
``` php
// bootstrap/app.php文件
// 实例化$app
$app = new Illuminate\Foundation\Application(
    realpath(__DIR__.'/../')
);

// 单例绑定共享的Kernel和异常处理器
$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;

  • 实例化$app

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    /**
     * Create a new Illuminate application instance.
     *
     * @param  string|null  $basePath
     * @return void
     */
    public function __construct($basePath = null)
    {
        // 设置基础路径
        if ($basePath) {
            $this->setBasePath($basePath);
        }

        // 注册基础绑定
        $this->registerBaseBindings();

        // 注册基础服务
        $this->registerBaseServiceProviders();

        // 注册核心容器别名
        $this->registerCoreContainerAliases();
    }

    • 设置基础路径
      在容器中设置app、/、config、public、storage、database等目录的路径

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      /**
       * Set the base path for the application.
       *
       * @param  string  $basePath
       * @return $this
       */
      public function setBasePath($basePath)
      {
          $this->basePath = rtrim($basePath, '\/');

          $this->bindPathsInContainer();

          return $this;
      }

      /**
       * Bind all of the application paths in the container.
       *
       * @return void
       */
      protected function bindPathsInContainer()
      {
          $this->instance('path', $this->path());
          $this->instance('path.base', $this->basePath());
          $this->instance('path.lang', $this->langPath());
          $this->instance('path.config', $this->configPath());
          $this->instance('path.public', $this->publicPath());
          $this->instance('path.storage', $this->storagePath());
          $this->instance('path.database', $this->databasePath());
          $this->instance('path.resources', $this->resourcePath());
          $this->instance('path.bootstrap', $this->bootstrapPath());
      }

      绑定后的数组 $this->instances 如下:

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      $this->instances['path'] = '/var/www/laravel/app';  
      $this->instances['path.base'] = '/var/www/laravel';  
      $this->instances['path.lang'] = '/var/www/laravel/resources/lang';  
      $this->instances['path.config'] = '/var/www/laravel/config';  
      $this->instances['path.public'] = '/var/www/laravel/public';  
      $this->instances['path.storage'] = '/var/www/laravel/storage';  
      $this->instances['path.database'] = '/var/www/laravel/database';  
      $this->instances['path.resources'] = '/var/www/laravel/resources';  
      $this->instances['path.bootstrap'] = '/var/www/laravel/bootstrap';

    • 注册基础绑定

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      /**
       * Register the basic bindings into the container.
       *
       * @return void
       */
      protected function registerBaseBindings()
      {
          static::setInstance($this);

          $this->instance('app', $this);

          $this->instance(Container::class, $this);

          // 包清单实例
          $this->instance(PackageManifest::class, new PackageManifest(
              new Filesystem, $this->basePath(), $this->getCachedPackagesPath()
          ));
      }

      追加$this->instances 如下:

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      $this->instances['app'] = object(Illuminate\Foundation\Application);  
      $this->instances['Illuminate\Container\Container'] = object(Illuminate\Foundation\Application);
      $this->instances['PackageManifest'] = object(PackageManifest);

    • 注册基础服务
      注册事件、日志、路由服务

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      /**
       * Register all of the base service providers.
       *
       * @return void
       */
      protected function registerBaseServiceProviders()
      {
          $this->register(new EventServiceProvider($this));

          $this->register(new LogServiceProvider($this));

          $this->register(new RoutingServiceProvider($this));
      }

      生成数组如下：

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      event:
      $this->bindings['events'] = [
          'concrete' => function ($app) {
                              return (new Dispatcher($app))->setQueueResolver(function () use ($app) {
                                  return $app->make(QueueFactoryContract::class);
                              });
                          }
          'shared' => 'true',
      ];
      log:
      $this->bindings['log'] = [
          'concrete' => function () {
                              return function createLogger()
                                      {
                                          $log = new Writer(
                                              new Monolog($this->channel()), $this->app['events']
                                          );

                                          if ($this->app->hasMonologConfigurator()) {
                                              call_user_func($this->app->getMonologConfigurator(), $log->getMonolog());
                                          } else {
                                              $this->{$this->{'configure'.ucfirst($this->handler()).'Handler'}($log)}($log);
                                          }

                                          return $log;
                                      }
                          }
          'shared' => 'true',
      ];
      router:
      $this->bindings['router'] = [
          'concrete' => function ($app) {
                              return new Router($app['events'], $app);
                          },
          'shared' => 'true',
      ];
      $this->bindings['url'] = [
          'concrete' => function ($app) {
                              $routes = $app['router']->getRoutes();

                              $app->instance('routes', $routes);

                              $url = new UrlGenerator(
                                  $routes, $app->rebinding(
                                      'request', $this->requestRebinder()
                                  )
                              );

                              $url->setSessionResolver(function () {
                                  return $this->app['session'];
                              });

                              $app->rebinding('routes', function ($app, $routes) {
                                  $app['url']->setRoutes($routes);
                              });

                              return $url;
                          },
          'shared' => 'true',
      ];
      $this->bindings['redirect'] = [
          'concrete' => function ($app) {
                          $redirector = new Redirector($app['url']);

                          if (isset($app['session.store'])) {
                              $redirector->setSession($app['session.store']);
                          }

                          return $redirector;
                      },
          'shared' => 'true',
      ];
      $this->bindings[ServerRequestInterface::class] = [
          'concrete' => function ($app) {
                              return (new DiactorosFactory)->createRequest($app->make('request'));
                          },
          'shared' => 'true',
      ];
      $this->bindings[ResponseInterface::class] = [
          'concrete' => function ($app) {
                              return new PsrResponse();
                          },
          'shared' => 'true',
      ];
      $this->bindings[ResponseFactoryContract::class] = [
          'concrete' => function ($app) {
                              return new ResponseFactory($app[ViewFactoryContract::class], $app['redirect']);
                          },
          'shared' => 'true',
      ];

    • 注册核心容器别名

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      public function registerCoreContainerAliases()
      {
          $aliases = [
              'app'                  => [\Illuminate\Foundation\Application::class, \Illuminate\Contracts\Container\Container::class, \Illuminate\Contracts\Foundation\Application::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],
          ];

          foreach ($aliases as $key => $aliases) {
              foreach ($aliases as $alias) {
                  $this->alias($key, $alias);
              }
          }
      }

      public function alias($abstract, $alias)
      {
          $this->aliases[$alias] = $abstract;

          $this->abstractAliases[$abstract][] = $alias;
      }

      生成数组如下：

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      $this->aliases['Illuminate\Foundation\Application'] = 'app';
      $this->aliases['Illuminate\Contracts\Container\Container'] = 'app';
      $this->aliases['Illuminate\Contracts\Foundation\Application'] = 'app';
      $this->abstractAliases['app'][] = 'Illuminate\Foundation\Application';
      $this->abstractAliases['app'][] = 'Illuminate\Contracts\Container\Container';
      $this->abstractAliases['app'][] = 'Illuminate\Contracts\Foundation\Application';
      ……

  • 单例绑定共享的Kernel和异常处理器
    单例绑定Http、Console的Kernel和异常处理器

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    $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
    );

总结：

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设置基础路径（$this->instances['path.*']） => 
注册基础绑定($this->instances['app|Container']) => 
注册基础服务($this->bindings[]) => 
注册核心容器别名($this->aliases[],$this->abstractAliases[])
至此，应用的实例化完成。

处理请求和响应

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// 通过前面在$app中注册的Illuminate\Contracts\Http\Kernel::class，现在获取Http实例
$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

// Kernel处理器调用handle方法处理当前请求，得到response
$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
);

// 发送响应信息到浏览器
$response->send();

// 请求结束，进行回调
$kernel->terminate($request, $response);

终于，laravel的启动讲完了。能看到这里说明你是一个有决心看源码的读者！加油，前路依然不平坦…
参考：https://segmentfault.com/a/1190000008848349

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