概述
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(IlluminateContractsHttpKernel::class); $response = $kernel->handle( $request = IlluminateHttpRequest::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bootstrapapp.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 IlluminateFoundationApplication( 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( IlluminateContractsHttpKernel::class, AppHttpKernel::class ); $app->singleton( IlluminateContractsConsoleKernel::class, AppConsoleKernel::class ); $app->singleton( IlluminateContractsDebugExceptionHandler::class, AppExceptionsHandler::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 $app;
请看app变量是IlluminateFoundationApplication类的对象,所以调用了这个类的构造函数,具体做了什么事,我们看源码。
public function __construct($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' => [IlluminateFoundationApplication::class, IlluminateContractsContainerContainer::class, IlluminateContractsFoundationApplication::class], 'auth' => [IlluminateAuthAuthManager::class, IlluminateContractsAuthFactory::class], 'auth.driver' => [IlluminateContractsAuthGuard::class], 'blade.compiler' => [IlluminateViewCompilersBladeCompiler::class], 'cache' => [IlluminateCacheCacheManager::class, IlluminateContractsCacheFactory::class], 'cache.store' => [IlluminateCacheRepository::class, IlluminateContractsCacheRepository::class], 'config' => [IlluminateConfigRepository::class, IlluminateContractsConfigRepository::class], 'cookie' => [IlluminateCookieCookieJar::class, IlluminateContractsCookieFactory::class, IlluminateContractsCookieQueueingFactory::class], 'encrypter' => [IlluminateEncryptionEncrypter::class, IlluminateContractsEncryptionEncrypter::class], 'db' => [IlluminateDatabaseDatabaseManager::class], 'db.connection' => [IlluminateDatabaseConnection::class, IlluminateDatabaseConnectionInterface::class], 'events' => [IlluminateEventsDispatcher::class, IlluminateContractsEventsDispatcher::class], 'files' => [IlluminateFilesystemFilesystem::class], 'filesystem' => [IlluminateFilesystemFilesystemManager::class, IlluminateContractsFilesystemFactory::class], 'filesystem.disk' => [IlluminateContractsFilesystemFilesystem::class], 'filesystem.cloud' => [IlluminateContractsFilesystemCloud::class], 'hash' => [IlluminateContractsHashingHasher::class], 'translator' => [IlluminateTranslationTranslator::class, IlluminateContractsTranslationTranslator::class], 'log' => [IlluminateLogWriter::class, IlluminateContractsLoggingLog::class, PsrLogLoggerInterface::class], 'mailer' => [IlluminateMailMailer::class, IlluminateContractsMailMailer::class, IlluminateContractsMailMailQueue::class], 'auth.password' => [IlluminateAuthPasswordsPasswordBrokerManager::class, IlluminateContractsAuthPasswordBrokerFactory::class], 'auth.password.broker' => [IlluminateAuthPasswordsPasswordBroker::class, IlluminateContractsAuthPasswordBroker::class], 'queue' => [IlluminateQueueQueueManager::class, IlluminateContractsQueueFactory::class, IlluminateContractsQueueMonitor::class], 'queue.connection' => [IlluminateContractsQueueQueue::class], 'queue.failer' => [IlluminateQueueFailedFailedJobProviderInterface::class], 'redirect' => [IlluminateRoutingRedirector::class], 'redis' => [IlluminateRedisRedisManager::class, IlluminateContractsRedisFactory::class], 'request' => [IlluminateHttpRequest::class, SymfonyComponentHttpFoundationRequest::class], 'router' => [IlluminateRoutingRouter::class, IlluminateContractsRoutingRegistrar::class, IlluminateContractsRoutingBindingRegistrar::class], 'session' => [IlluminateSessionSessionManager::class], 'session.store' => [IlluminateSessionStore::class, IlluminateContractsSessionSession::class], 'url' => [IlluminateRoutingUrlGenerator::class, IlluminateContractsRoutingUrlGenerator::class], 'validator' => [IlluminateValidationFactory::class, IlluminateContractsValidationFactory::class], 'view' => [IlluminateViewFactory::class, IlluminateContractsViewFactory::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AppHttpKernel.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 AppHttp; use IlluminateFoundationHttpKernel 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 = [ IlluminateFoundationHttpMiddlewareCheckForMaintenanceMode::class, //AppHttpMiddlewareMyMiddleware::class, ]; /** * The application's route middleware groups. * * @var array */ protected $middlewareGroups = [ 'web' => [ AppHttpMiddlewareEncryptCookies::class, IlluminateCookieMiddlewareAddQueuedCookiesToResponse::class, IlluminateSessionMiddlewareStartSession::class, IlluminateViewMiddlewareShareErrorsFromSession::class, AppHttpMiddlewareVerifyCsrfToken::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' => AppHttpMiddlewareAuthenticate::class, 'auth.basic' => IlluminateAuthMiddlewareAuthenticateWithBasicAuth::class, 'guest' => AppHttpMiddlewareRedirectIfAuthenticated::class, 'throttle' => IlluminateRoutingMiddlewareThrottleRequests::class, 'mymiddleware'=>AppHttpMiddlewareMyMiddleware::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 = IlluminateHttpRequest::capture() ); $response->send();
最后在中止,释放所有资源。
/** * Call the terminate method on any terminable middleware. * * @param IlluminateHttpRequest $request * @param IlluminateHttpResponse $response * @return void */ public function terminate($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bootstrapapp.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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