Application是所有应用程序类的基类，接下来了解一下它的源码。yii2\base\Application.php。
<?php
/**
* @link http://www.yiiframework.com/
* @copyright Copyright (c) 2008 Yii Software LLC
* @license http://www.yiiframework.com/license/
*/ namespace yii\base; use Yii; /**
* Application is the base class for all application classes.
* 是所有应用程序类的基类
* @property \yii\web\AssetManager $assetManager The asset manager application component. This property is
* read-only.资产管理器应用组件，只读
* @property \yii\rbac\ManagerInterface $authManager The auth manager application component. Null is returned
* if auth manager is not configured. This property is read-only.认证管理器应用程序组件。未配置返回null，只读
* @property string $basePath The root directory of the application. 应用程序的根目录。
* @property \yii\caching\Cache $cache The cache application component. Null if the component is not enabled.
* This property is read-only.缓存应用程序组件。
* @property \yii\db\Connection $db The database connection. This property is read-only.数据库连接。
* @property \yii\web\ErrorHandler|\yii\console\ErrorHandler $errorHandler The error handler application
* component. This property is read-only.错误处理程序应用程序组件
* @property \yii\i18n\Formatter $formatter The formatter application component. This property is read-only.
* 格式化程序的应用程序组件。
* @property \yii\i18n\I18N $i18n The internationalization application component. This property is read-only.
* 国际化应用组件。
* @property \yii\log\Dispatcher $log The log dispatcher application component. This property is read-only.
* 日志调度程序组件。
* @property \yii\mail\MailerInterface $mailer The mailer application component. This property is read-only.
* 邮件应用程序组件。
* @property \yii\web\Request|\yii\console\Request $request The request component. This property is read-only.
* 请求组件。
* @property \yii\web\Response|\yii\console\Response $response The response component. This property is
* read-only.反应元件。
* @property string $runtimePath The directory that stores runtime files. Defaults to the "runtime"
* subdirectory under [[basePath]].存储运行时文件的目录。
* @property \yii\base\Security $security The security application component. This property is read-only.
* 安全应用组件。
* @property string $timeZone The time zone used by this application.该应用程序使用的时区。
* @property string $uniqueId The unique ID of the module. This property is read-only.模块的唯一标识。
* @property \yii\web\UrlManager $urlManager The URL manager for this application. This property is read-only.
* 此应用程序的网址管理器。
* @property string $vendorPath The directory that stores vendor files. Defaults to "vendor" directory under
* [[basePath]].存储供应商文件的目录。
* @property View|\yii\web\View $view The view application component that is used to render various view
* files. This property is read-only.用于呈现各种视图文件的视图应用程序组件
*
* @author Qiang Xue <qiang.xue@gmail.com>
* @since 2.0
*/
abstract class Application extends Module
{
/**
* @event Event an event raised before the application starts to handle a request.
* 在应用程序开始处理请求之前提出的事件。
*/
const EVENT_BEFORE_REQUEST = 'beforeRequest';
/**
* @event Event an event raised after the application successfully handles a request (before the response is sent out).
* 该应用程序成功处理请求后提出的事件
*/
const EVENT_AFTER_REQUEST = 'afterRequest';
/**
* Application state used by [[state]]: application just started.
* [[state]]适用状态：刚开始应用
*/
const STATE_BEGIN = ;
/**
* Application state used by [[state]]: application is initializing.
* [[state]]应用程序状态：应用程序初始化。
*/
const STATE_INIT = ;
/**
* Application state used by [[state]]: application is triggering [[EVENT_BEFORE_REQUEST]].
* [[state]]应用程序状态：应用触发[[EVENT_BEFORE_REQUEST]]
*/
const STATE_BEFORE_REQUEST = ;
/**
* Application state used by [[state]]: application is handling the request.
* [[state]]应用程序状态：应用程序处理请求。
*/
const STATE_HANDLING_REQUEST = ;
/**
* Application state used by [[state]]: application is triggering [[EVENT_AFTER_REQUEST]]..
* [[state]]应用程序状态：应用触发[[EVENT_AFTER_REQUEST]]
*/
const STATE_AFTER_REQUEST = ;
/**
* Application state used by [[state]]: application is about to send response.
* [[state]]应用程序状态：应用程序即将发送响应。
*/
const STATE_SENDING_RESPONSE = ;
/**
* Application state used by [[state]]: application has ended.
* [[state]]应用程序状态：应用程序结束。
*/
const STATE_END = ; /**
* @var string the namespace that controller classes are located in.控制器类的命名空间位置。
* This namespace will be used to load controller classes by prepending it to the controller class name.
* The default namespace is `app\controllers`.
* 此命名空间将用于负载控制器类重写它的控制器类的名字。 默认命名空间是`app\controllers`。
* Please refer to the [guide about class autoloading](guide:concept-autoloading.md) for more details.
*/
public $controllerNamespace = 'app\\controllers';
/**
* @var string the application name.应用程序名称。
*/
public $name = 'My Application';
/**
* @var string the version of this application.此应用程序的版本。
*/
public $version = '1.0';
/**
* @var string the charset currently used for the application.目前使用的字符集。
*/
public $charset = 'UTF-8';
/**
* @var string the language that is meant to be used for end users. It is recommended that you
* use [IETF language tags](http://en.wikipedia.org/wiki/IETF_language_tag). For example, `en` stands
* for English, while `en-US` stands for English (United States).
* 用来作为终端用户使用的语言
* @see sourceLanguage
*/
public $language = 'en-US';
/**
* @var string the language that the application is written in. This mainly refers to
* the language that the messages and view files are written in.
* 应用程序编写的语言。
* @see language
*/
public $sourceLanguage = 'en-US';
/**
* @var Controller the currently active controller instance当前活动控制器实例
*/
public $controller;
/**
* @var string|boolean the layout that should be applied for views in this application. Defaults to 'main'.
* If this is false, layout will be disabled.
* 该应用程序中应用的布局。
*/
public $layout = 'main';
/**
* @var string the requested route请求的路径 请求的路径
*/
public $requestedRoute;
/**
* @var Action the requested Action. If null, it means the request cannot be resolved into an action.
* 操作所要求的行动
*/
public $requestedAction;
/**
* @var array the parameters supplied to the requested action.
* 所请求的动作提供的参数。
*/
public $requestedParams;
/**
* @var array list of installed Yii extensions. Each array element represents a single extension
* with the following structure:
* 安装Yii扩展名列表。每个数组元素代表一个扩展
*
* ~~~
* [
* 'name' => 'extension name',
* 'version' => 'version number',
* 'bootstrap' => 'BootstrapClassName', // optional, may also be a configuration array
* 'alias' => [
* '@alias1' => 'to/path1',
* '@alias2' => 'to/path2',
* ],
* ]
* ~~~
*
* The "bootstrap" class listed above will be instantiated during the application
* [[bootstrap()|bootstrapping process]]. If the class implements [[BootstrapInterface]],
* its [[BootstrapInterface::bootstrap()|bootstrap()]] method will be also be called.
*
* If not set explicitly in the application config, this property will be populated with the contents of
* 如果在应用程序配置中没有设置，该属性将填充到内容
* @vendor/yiisoft/extensions.php`.
*/
public $extensions;
/**
* @var array list of components that should be run during the application [[bootstrap()|bootstrapping process]].
* 组件的列表，运行在 [[bootstrap()|bootstrapping process]]中的应用
* Each component may be specified in one of the following formats:
*
* - an application component ID as specified via [[components]].
* - a module ID as specified via [[modules]].
* - a class name.
* - a configuration array.
*
* During the bootstrapping process, each component will be instantiated. If the component class
* implements [[BootstrapInterface]], its [[BootstrapInterface::bootstrap()|bootstrap()]] method
* will be also be called.
* 在整个启动过程中，每个组件被实例化。如果组件类提到 [[BootstrapInterface]]，
* [[BootstrapInterface::bootstrap()|bootstrap()]]方法也会调用
*/
public $bootstrap = [];
/**
* @var integer the current application state during a request handling life cycle.
* This property is managed by the application. Do not modify this property.
* 在请求处理生命周期中的当前应用程序状态。属性由应用程序管理。不要修改此属性。
*/
public $state;
/**
* @var array list of loaded modules indexed by their class names.
* 加载模块列表由它们的类名称索引组成。
*/
public $loadedModules = []; /**
* Constructor.构造函数
* @param array $config name-value pairs that will be used to initialize the object properties.
* Note that the configuration must contain both [[id]] and [[basePath]].
* 用来初始化对象属性的 name-value 注意配置必须包含[[id]] 和[[basePath]].
* @throws InvalidConfigException if either [[id]] or [[basePath]] configuration is missing.
* 如果是修改[[id]] 或[[basePath]] 则配置丢失。
*/
public function __construct($config = [])
{
Yii::$app = $this;// 将自身的实例绑到Yii的$app上
$this->setInstance($this);// 将自身加入到loadedModules中 $this->state = self::STATE_BEGIN;// 设置状态为刚开始 // 做预处理配置
$this->preInit($config); $this->registerErrorHandler($config); Component::__construct($config);
} /**
* Pre-initializes the application. 初始化应用。
* This method is called at the beginning of the application constructor.
* It initializes several important application properties.
* 在构造函数中调用该方法，用于初始化一些重要的属性
* If you override this method, please make sure you call the parent implementation.
* @param array $config the application configuration 应用的配置
* @throws InvalidConfigException if either [[id]] or [[basePath]] configuration is missing.
*/
public function preInit(&$config)
{
// 使用了&符号，表示$config的修改会保留
if (!isset($config['id'])) {//判断配置中是否有application ID ，如果没有，抛出异常
throw new InvalidConfigException('The "id" configuration for the Application is required.');
}
if (isset($config['basePath'])) {
// 是否配置项目的root路径
$this->setBasePath($config['basePath']);
//赋值给模块的_basepath属性，并在设置后删除
unset($config['basePath']);
} else {//否则抛出异常
throw new InvalidConfigException('The "basePath" configuration for the Application is required.');
}
//如果配置文件中设置了 vendorPath 使用配置的值，并在设置后删除，否则使用默认的
if (isset($config['vendorPath'])) {
$this->setVendorPath($config['vendorPath']);
unset($config['vendorPath']);
} else {
// set "@vendor"
$this->getVendorPath();
}
//如果配置文件中设置了 runtimePath 使用配置的值，并在设置后删除，否则使用默认的
if (isset($config['runtimePath'])) {
$this->setRuntimePath($config['runtimePath']);
unset($config['runtimePath']);
} else {
// set "@runtime"
$this->getRuntimePath();
}
//如果配置文件中设置了 timeZone 使用配置的值，并在设置后删除，否则使用默认的时区
if (isset($config['timeZone'])) {
$this->setTimeZone($config['timeZone']);
unset($config['timeZone']);
} elseif (!ini_get('date.timezone')) {
$this->setTimeZone('UTC');
} // merge core components with custom components
foreach ($this->coreComponents() as $id => $component) {
if (!isset($config['components'][$id])) {
// 如果配置中没有配置相应的核心component，就赋给它
$config['components'][$id] = $component;
} elseif (is_array($config['components'][$id]) && !isset($config['components'][$id]['class'])) {
// 如果存在相应的核心component，但没有定义它的class，就直接赋到class的key上
$config['components'][$id]['class'] = $component['class'];
}
}
} /**
* @inheritdoc
*/
public function init()
{
$this->state = self::STATE_INIT;
$this->bootstrap();
} /**
* Initializes extensions and executes bootstrap components.初始化扩展并执行初始化程序组件
* This method is called by [[init()]] after the application has been fully configured.
* 该方法在应用完全配置后被[[init()]]调用
* If you override this method, make sure you also call the parent implementation.
*/
protected function bootstrap()
{
if ($this->extensions === null) {//如果没有配置，则调用Yii的默认扩展组件
$file = Yii::getAlias('@vendor/yiisoft/extensions.php');
$this->extensions = is_file($file) ? include($file) : [];
}
foreach ($this->extensions as $extension) {
if (!empty($extension['alias'])) {//如果扩展组件有设置别名
foreach ($extension['alias'] as $name => $path) {
Yii::setAlias($name, $path);//将给扩展的别名注册到别名数组中
}
}
if (isset($extension['bootstrap'])) {//如果扩展组件有[[bootstrap]]配置 则初始化给扩展组件
$component = Yii::createObject($extension['bootstrap']);
if ($component instanceof BootstrapInterface) {
Yii::trace("Bootstrap with " . get_class($component) . '::bootstrap()', __METHOD__);
$component->bootstrap($this);
} else {
Yii::trace("Bootstrap with " . get_class($component), __METHOD__);
}
}
} foreach ($this->bootstrap as $class) {
$component = null;
if (is_string($class)) {
if ($this->has($class)) {
$component = $this->get($class);
} elseif ($this->hasModule($class)) {
$component = $this->getModule($class);
} elseif (strpos($class, '\\') === false) {
throw new InvalidConfigException("Unknown bootstrapping component ID: $class");
}
}
if (!isset($component)) {//如果不存在，则调用Yii创建对象
$component = Yii::createObject($class);
} if ($component instanceof BootstrapInterface) {
Yii::trace("Bootstrap with " . get_class($component) . '::bootstrap()', __METHOD__);
$component->bootstrap($this);
} else {
Yii::trace("Bootstrap with " . get_class($component), __METHOD__);
}
}
}
未完待续。