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。
<?phprequire __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?
<?phpnamespace 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
更多关于Laravel相关内容感兴趣的读者可查看本站专题:《Laravel框架入门与进阶教程》、《php优秀开发框架总结》、《php面向对象程序设计入门教程》、《php+mysql数据库操作入门教程》及《php常见数据库操作技巧汇总》
希望本文所述对大家基于Laravel框架的PHP程序设计有所帮助。
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