本文实例讲述了Laravel框架生命周期与原理。分享给大家供大家参考,具体如下:
引言:
如果你对一件工具的使用原理了如指掌,那么你在用这件工具的时候会充满信心!
正文:
一旦用户(浏览器)发送了一个HTTP请求,我们的apache或者nginx一般都转到index.php,因此,之后的一系列步骤都是从index.php开始的,我们先来看一看这个文件代码。
<?php require __DIR__.'/../bootstrap/autoload.php'; $app = require_once __DIR__.'/../bootstrap/app.php'; /* |-------------------------------------------------------------------------- | Run The Application |-------------------------------------------------------------------------- | | Once we have the application, we can handle the incoming request | through the kernel, and send the associated response back to | the client's browser allowing them to enjoy the creative | and wonderful application we have prepared for them. | */ $kernel = $app->make(Illuminate\Contracts\Http\Kernel::class); $response = $kernel->handle( $request = Illuminate\Http\Request::capture() ); $response->send(); $kernel->terminate($request, $response);
作者在注释里谈了kernel的作用,kernel的作用,kernel处理来访的请求,并且发送相应返回给用户浏览器。
这里又涉及到了一个app对象,所以附上app对象,所以附上app对象的源码,这份源码是\bootstrap\app.php
<?php /* |-------------------------------------------------------------------------- | Create The Application |-------------------------------------------------------------------------- | | The first thing we will do is create a new Laravel application instance | which serves as the "glue" for all the components of Laravel, and is | the IoC container for the system binding all of the various parts. | */ $app = new Illuminate\Foundation\Application( realpath(__DIR__.'/../') ); /* |-------------------------------------------------------------------------- | Bind Important Interfaces |-------------------------------------------------------------------------- | | Next, we need to bind some important interfaces into the container so | we will be able to resolve them when needed. The kernels serve the | incoming requests to this application from both the web and CLI. | */ $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 The Application |-------------------------------------------------------------------------- | | This script returns the application instance. The instance is given to | the calling script so we can separate the building of the instances | from the actual running of the application and sending responses. | */ return $app;
请看app变量是Illuminate\Foundation\Application类的对象,所以调用了这个类的构造函数,具体做了什么事,我们看源码。
public function __construct($basePath = null) { if ($basePath) { $this->setBasePath($basePath); } $this->registerBaseBindings(); $this->registerBaseServiceProviders(); $this->registerCoreContainerAliases(); }
构造器做了3件事,前两件事很好理解,创建Container,注册了ServiceProvider,看代码
/** * Register the basic bindings into the container. * * @return void */ protected function registerBaseBindings() { static::setInstance($this); $this->instance('app', $this); $this->instance(Container::class, $this); } /** * 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)); }
最后一件事,是做了个很大的数组,定义了大量的别名,侧面体现程序员是聪明的懒人。
/** * Register the core class aliases in the container. * * @return void */ 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); } } }
这里出现了一个instance函数,其实这并不是Application类的函数,而是Application类的父类Container类的函数
/** * Register an existing instance as shared in the container. * * @param string $abstract * @param mixed $instance * @return void */ public function instance($abstract, $instance) { $this->removeAbstractAlias($abstract); unset($this->aliases[$abstract]); // We'll check to determine if this type has been bound before, and if it has // we will fire the rebound callbacks registered with the container and it // can be updated with consuming classes that have gotten resolved here. $this->instances[$abstract] = $instance; if ($this->bound($abstract)) { $this->rebound($abstract); } }
Application是Container的子类,所以$app
不仅是Application类的对象,还是Container的对象,所以,新出现的singleton函数我们就可以到Container类的源代码文件里查。bind函数和singleton的区别见这篇博文。
singleton这个函数,前一个参数是实际类名,后一个参数是类的“别名”。
$app
对象声明了3个单例模型对象,分别是HttpKernel,ConsoleKernel,ExceptionHandler。请注意,这里并没有创建对象,只是声明,也只是起了一个“别名”。
大家有没有发现,index.php中也有一个$kernel变量,但是只保存了make出来的HttpKernel变量,因此本文不再讨论,ConsoleKernel,ExceptionHandler。。。
继续在文件夹下找到App\Http\Kernel.php,既然我们把实际的HttpKernel做的事情都写在这个php文件里,就从这份代码里看看究竟做了哪些事?
<?php namespace App\Http; use Illuminate\Foundation\Http\Kernel as HttpKernel; class Kernel extends HttpKernel { /** * The application's global HTTP middleware stack. * * These middleware are run during every request to your application. * * @var array */ protected $middleware = [ \Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode::class, //\App\Http\Middleware\MyMiddleware::class, ]; /** * 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\View\Middleware\ShareErrorsFromSession::class, \App\Http\Middleware\VerifyCsrfToken::class, ], 'api' => [ 'throttle:60,1', ], ]; /** * 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, 'guest' => \App\Http\Middleware\RedirectIfAuthenticated::class, 'throttle' => \Illuminate\Routing\Middleware\ThrottleRequests::class, 'mymiddleware'=>\App\Http\Middleware\MyMiddleware::class, ]; }
一目了然,HttpKernel里定义了中间件数组。
该做的做完了,就开始了请求到响应的过程,见index.php
$response = $kernel->handle( $request = Illuminate\Http\Request::capture() ); $response->send();
最后在中止,释放所有资源。
/** * Call the terminate method on any terminable middleware. * * @param \Illuminate\Http\Request $request * @param \Illuminate\Http\Response $response * @return void */ public function terminate($request, $response) { $this->terminateMiddleware($request, $response); $this->app->terminate(); }
总结一下,简单归纳整个过程就是:
1.index.php加载\bootstrap\app.php,在Application类的构造函数中创建Container,注册了ServiceProvider,定义了别名数组,然后用app变量保存构造函数构造出来的对象。
2.使用app这个对象,创建1个单例模式的对象HttpKernel,在创建HttpKernel时调用了构造函数,完成了中间件的声明。
3.以上这些工作都是在请求来访之前完成的,接下来开始等待请求,然后就是:接受到请求-->处理请求-->发送响应-->中止app变量
希望本文所述对大家基于Laravel框架的PHP程序设计有所帮助。
Laravel框架生命周期与原理分析
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