YII 的源码分析(-)，yii源码分析
做为源码分析的首秀，我就挑了yii(读作歪依依而不是歪爱爱)；它的赞美之词我就不多说了，直接入正题。先准备材料，建议直从官网下载yii的源码包（1.1.15）最新版本。
在demos里边有一个最简单的应用—helloworld.就是用yii框架输出一句话：”hello world”;
我就从它下手，分析框架执行一个最小流程要经过哪些组件，浅析它的运行过程。
首先从单一入口文件开始阅读。（源码一般都是从调用处开始分析）
Index.php->
// include Yii bootstrap file
//引入启动文件
require_once(dirname(__FILE__).'/../../framework/yii.php');
yii.php ->
//YiiBase is a helper class serving common framework functionalities.
//YiiBase是一个助手类，它服务于整个框架。 这里定义了许多重要的常量
require(dirname(__FILE__).'/YiiBase.php');
//注册自动加载类
spl_autoload_register(array('YiiBase','autoload'));
//导入接口类
require(YII_PATH.'/base/interfaces.php');
//启动应用
Yii::createWebApplication()->run();
代码到这里似乎就终结了，页面的内容也程现出来，可是框架到底做了些什么，我们却一无所知。所以我们需要把这一步进行分解，把里边的细节暴露出来。
Yii::createWebApplication()->run() 一共可以分成三部分
Yii 这个东西是什么？
从yii.php 可以找到这样一行代码class Yii extends YiiBase
说明它就是YiiBase的继承类，而且作者的扩展是留空的，所以Yii就是YiiBase的一个引用而已。所以createWebApplication这个静态方法也得去YiiBase中查找了。
在YiiBase.php中，很容易就发现了这个方法：
public static function createWebApplication($config=null)
{
return self::createApplication('CWebApplication',$config);
}
它又把任务传递给了createApplication：
public static function createApplication($class,$config=null)
{
return new $class($config);
}
结合起来看，createWebApplication () 就是return new CWebApplication($config);
这个CWebApplication类又在哪呢？它又是怎么引入的呢？
带着一系列的问题，我又回到了YiiBase.php
那里边定义了一个很长的数组，你可以找到：
'CWebApplication' => '/web/CWebApplication.php',这就是自动加载类中的一员
关于它是如何实现自动加载的，可以查看spl_autoload_register的相关文档，此处就节外生枝了.
我们继续往CWebApplication这个里边深挖。打开/web/CWebApplication.php这个文件。
前面提到return new CWebApplication($config);根据我的经验，用了new ,通常会有一个构造函数的，但我却没有找到它的构造函数，肯定是在它的父类中，于是我往上找，class CWebApplication extends CApplication 果然被我发现了，这就跟挖泥鳅一样的，得顺着线索一点点的找，要有耐心。
CApplication 中果然有构造函数，代码如下：
<span><span>public</span> <span>function</span> __construct(<span>$config</span>=<span>null</span><span>)
{
Yii</span>::setApplication(<span>$this</span><span>);
</span><span>//</span><span> set basePath at early as possible to avoid trouble</span>
<span>if</span>(<span>is_string</span>(<span>$config</span><span>))
</span><span>$config</span>=<span>require</span>(<span>$config</span><span>);
</span><span>if</span>(<span>isset</span>(<span>$config</span>['basePath'<span>]))
{
</span><span>$this</span>->setBasePath(<span>$config</span>['basePath'<span>]);
</span><span>unset</span>(<span>$config</span>['basePath'<span>]);
}
</span><span>else</span>
<span>$this</span>->setBasePath('protected'<span>);
Yii</span>::setPathOfAlias('application',<span>$this</span>-><span>getBasePath());
Yii</span>::setPathOfAlias('webroot',<span>dirname</span>(<span>$_SERVER</span>['SCRIPT_FILENAME'<span>]));
</span><span>if</span>(<span>isset</span>(<span>$config</span>['extensionPath'<span>]))
{
</span><span>$this</span>->setExtensionPath(<span>$config</span>['extensionPath'<span>]);
</span><span>unset</span>(<span>$config</span>['extensionPath'<span>]);
}
</span><span>else</span><span>
Yii</span>::setPathOfAlias('ext',<span>$this</span>->getBasePath().DIRECTORY_SEPARATOR.'extensions'<span>);
</span><span>if</span>(<span>isset</span>(<span>$config</span>['aliases'<span>]))
{
</span><span>$this</span>->setAliases(<span>$config</span>['aliases'<span>]);
</span><span>unset</span>(<span>$config</span>['aliases'<span>]);
}</span></span>Copy after login
//以上都可以看成是初始化，设置类的引用，别名，路径什么的。
$this->preinit();//暂时未发现有什么用，估计是留给后面扩展用的
$this->initSystemHandlers();//设置错误处理
$this->registerCoreComponents();//注册核心组件
$this->configure($config); //通过配置文件扩展类的属性，为空的时候什么也不做
$this->attachBehaviors($this->behaviors);
$this->preloadComponents();
$this->init();
}
$this下面的某些方法，在当前类是找不到的，因为它们可能是来自父类，最简单的方法就是ctrl+f搜索一下，没有就去类的声明处查看：
abstract class CApplication extends CModule
显然要进入CModule，如果此时还找不到想要方法，那么继续上一过程：
abstract class CModule extends CComponent
直到class CComponent
说明这就是当前这些家伙的老巢了。从代码的中注释中也可以看到：
CComponent is the base class for all components
说明我的想法是正确的，没错，它就是基类。
透过代码，我们可以发现，我们当前的应用，因为很多参数是空，所以很多逻辑都是直接跳过的。
看到这，$this的内容也大致明了啦。我们再回头看看
return new CWebApplication($config)->run();
通过前面的层层分析，此时的run方法也很好找了。就在CApplication 里边：
<span><span>public</span> <span>function</span><span> run()
{
</span><span>if</span>(<span>$this</span>->hasEventHandler('onBeginRequest'<span>)){
</span><span>$this</span>->onBeginRequest(<span>new</span> CEvent(<span>$this</span><span>));
}
</span><span>register_shutdown_function</span>(<span>array</span>(<span>$this</span>,'end'),0,<span>false</span><span>);
</span><span>$this</span>-><span>processRequest();
</span><span>if</span>(<span>$this</span>->hasEventHandler('onEndRequest'<span>)){
</span><span>$this</span>->onEndRequest(<span>new</span> CEvent(<span>$this</span><span>));
}
}</span></span>Copy after login
重点放在：$this->processRequest(); 因为前面和后面部分都是注册事件相关的，当前条件下执行不到。
<span><span>abstract</span> <span>public</span> <span>function</span> processRequest(); 这个方法在当前类中是抽象的，所以肯定在它的子类中实现了。回去找CWebApplication:
<span>public</span> <span>function</span><span> processRequest()
{
</span><span>if</span>(<span>is_array</span>(<span>$this</span>->catchAllRequest) && <span>isset</span>(<span>$this</span>->catchAllRequest[0<span>]))
{
</span><span>$route</span>=<span>$this</span>->catchAllRequest[0<span>];
</span><span>foreach</span>(<span>array_splice</span>(<span>$this</span>->catchAllRequest,1) <span>as</span> <span>$name</span>=><span>$value</span><span>)
</span><span>$_GET</span>[<span>$name</span>]=<span>$value</span><span>;
}
</span><span>else</span>
<span>$route</span>=<span>$this</span>->getUrlManager()->parseUrl(<span>$this</span>-><span>getRequest());
</span><span>$this</span>->runController(<span>$route</span><span>);
}</span></span>Copy after login
注意重点在$this->runController($route);
<span><span>public</span> <span>function</span> runController(<span>$route</span><span>)
{
</span><span>if</span>((<span>$ca</span>=<span>$this</span>->createController(<span>$route</span>))!==<span>null</span><span>)
{
</span><span>list</span>(<span>$controller</span>,<span>$actionID</span>)=<span>$ca</span><span>;
</span><span>$oldController</span>=<span>$this</span>-><span>_controller;
</span><span>$this</span>->_controller=<span>$controller</span><span>;
</span><span>$controller</span>-><span>init();
</span><span>$controller</span>->run(<span>$actionID</span><span>);
</span><span>$this</span>->_controller=<span>$oldController</span><span>;
}
</span><span>else</span>
<span>throw</span> <span>new</span> CHttpException(404,Yii::t('yii','Unable to resolve the request "{route}".',
<span>array</span>('{route}'=><span>$route</span>===''?<span>$this</span>->defaultController:<span>$route</span><span>)));
}</span></span>Copy after login
我们要注意的代码只有两行：
$controller->init();
$controller->run($actionID);
这里的$controller可以能过查看createController得知，就是默认的控制器Sitecontroller.php
而Action则是index,你问我是怎么看出来的？哈哈，我在猜不出来的地方echo或var_dump一下不就可以了吗？这么简单的逻辑，还轮不到xdebug 这样的神器出场。
显然，init什么也没有做，看看run做了什么
Sitecontroller中没有run方法，又要去它的父类中查找。
class SiteController extends CController
在CController中有这个方法：
<span><span>public</span> <span>function</span> run(<span>$actionID</span><span>)
{
</span><span>if</span>((<span>$action</span>=<span>$this</span>->createAction(<span>$actionID</span>))!==<span>null</span><span>)
{
</span><span>if</span>((<span>$parent</span>=<span>$this</span>->getModule())===<span>null</span><span>){
</span><span>$parent</span>=Yii::<span>app();
}
</span><span>if</span>(<span>$parent</span>->beforeControllerAction(<span>$this</span>,<span>$action</span><span>))
{
</span><span>$this</span>->runActionWithFilters(<span>$action</span>,<span>$this</span>-><span>filters());
</span><span>$parent</span>->afterControllerAction(<span>$this</span>,<span>$action</span><span>);
}
}
</span><span>else</span>
<span>$this</span>->missingAction(<span>$actionID</span><span>);
}
</span></span>Copy after login
能过查看$this->createAction($actionID)，得到return new CInlineAction($this,$actionID);
我们呆会再看这个CInlineAction,先看$this->runActionWithFilters($action,$this->filters());
<span><span>public</span> <span>function</span> runActionWithFilters(<span>$action</span>,<span>$filters</span><span>)
{
</span><span>if</span>(<span>empty</span>(<span>$filters</span><span>)){
</span><span>$this</span>->runAction(<span>$action</span><span>);
}
</span><span>else</span><span>
{
</span><span>$priorAction</span>=<span>$this</span>-><span>_action;
</span><span>$this</span>->_action=<span>$action</span><span>;
CFilterChain</span>::create(<span>$this</span>,<span>$action</span>,<span>$filters</span>)-><span>run();
</span><span>$this</span>->_action=<span>$priorAction</span><span>;
}
}</span></span>Copy after login
显然$filters是空的，所以执行第一个表达式$this->runAction($action);
<span><span>public</span> <span>function</span> runAction(<span>$action</span><span>)
{
</span><span>$priorAction</span>=<span>$this</span>-><span>_action;
</span><span>$this</span>->_action=<span>$action</span><span>;
</span><span>if</span>(<span>$this</span>->beforeAction(<span>$action</span><span>))
{
</span><span>if</span>(<span>$action</span>->runWithParams(<span>$this</span>->getActionParams())===<span>false</span><span>){
</span><span>$this</span>->invalidActionParams(<span>$action</span><span>);
}
</span><span>else</span><span>{
</span><span>$this</span>->afterAction(<span>$action</span><span>);
}
}
</span><span>$this</span>->_action=<span>$priorAction</span><span>;
}</span></span>Copy after login
这段代码的重点是 $action->runWithParams($this->getActionParams())这一句；
这里的$action就是$this->createAction($actionID)返回的结果，而它的结果就是
return new CInlineAction($this,$actionID);
CInlineAction.php
是时候查看CInlineAction了；
<span> <span>public</span> <span>function</span> runWithParams(<span>$params</span><span>)
{
</span><span>$methodName</span>='action'.<span>$this</span>-><span>getId();
</span><span>$controller</span>=<span>$this</span>-><span>getController();
</span><span>$method</span>=<span>new</span> ReflectionMethod(<span>$controller</span>, <span>$methodName</span><span>);
</span><span>if</span>(<span>$method</span>->getNumberOfParameters()>0<span>)
</span><span>return</span> <span>$this</span>->runWithParamsInternal(<span>$controller</span>, <span>$method</span>, <span>$params</span><span>);
</span><span>else</span>
<span>return</span> <span>$controller</span>-><span>$methodName</span><span>();
}</span></span>Copy after login
哇哦，好高级，居然还用了反射，不过我喜欢！
不过呢，打印$method发现：
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
