Yii框架分析(一)入口脚本index.php的启动过程剖析

$yii=dirname(__FILE__).’/../framework/yii.php’;
$config=dirname(__FILE__).’/protected/config/main.php’;

// remove the following line when in production mode
defined(‘YII_DEBUG’) or define(‘YII_DEBUG’,true);

require_once($yii);
Yii::createWebApplication($config)->run();

class Yii extends YiiBase
{
}

public static function autoload($className)
{
    // use include so that the error PHP file may appear
    if(isset(self::$_coreClasses[$className]))
        include(YII_PATH.self::$_coreClasses[$className]);
    else if(isset(self::$_classes[$className]))
        include(self::$_classes[$className]);
    else
        include($className.’.php’);
}

private static $_coreClasses=array(
    ‘CApplication’ => ‘/base/CApplication.php’,
    ‘CBehavior’ => ‘/base/CBehavior.php’,
    ‘CComponent’ => ‘/base/CComponent.php’,
    …
)

public static function createWebApplication($config=null)
{
    return new CWebApplication($config);
}

public function __construct($config=null)
{
    Yii::setApplication($this);
    // set basePath at early as possible to avoid trouble
    if(is_string($config))
        $config=require($config);
    if(isset($config['basePath']))
    {
        $this->setBasePath($config['basePath']);
        unset($config['basePath']);
    }
    else
        $this->setBasePath(‘protected’);
    Yii::setPathOfAlias(‘application’,$this->getBasePath());
    Yii::setPathOfAlias(‘webroot’,dirname($_SERVER['SCRIPT_FILENAME']));

    $this->preinit();

    $this->initSystemHandlers();
    $this->registerCoreComponents();

    $this->configure($config);
    $this->attachBehaviors($this->behaviors);
    $this->preloadComponents();

    $this->init();
}

Yii::setPathOfAlias(‘application’,$this->getBasePath());
Yii::setPathOfAlias(‘webroot’,dirname($_SERVER['SCRIPT_FILENAME']));

/**
* Initializes the class autoloader and error handlers.
*/
protected function initSystemHandlers()
{
    if(YII_ENABLE_EXCEPTION_HANDLER)
        set_exception_handler(array($this,’handleException’));
    if(YII_ENABLE_ERROR_HANDLER)
        set_error_handler(array($this,’handleError’),error_reporting());
}

protected function registerCoreComponents()
{
    parent::registerCoreComponents();

    $components=array(
        ‘urlManager’=>array(
            ‘class’=>’CUrlManager’,
        ),
        ‘request’=>array(
            ‘class’=>’CHttpRequest’,
        ),
        ‘session’=>array(
            ‘class’=>’CHttpSession’,
        ),
        ‘assetManager’=>array(
            ‘class’=>’CAssetManager’,
         ),
        ‘user’=>array(
            ‘class’=>’CWebUser’,
         ),
        ‘themeManager’=>array(
            ‘class’=>’CThemeManager’,
        ),
        ‘authManager’=>array(
            ‘class’=>’CPhpAuthManager’,
        ),
        ‘clientScript’=>array(
            ‘class’=>’CClientScript’,
        ),
    );

    $this->setComponents($components);
}

public function configure($config)
{
    if(is_array($config))
    {
        foreach($config as $key=>$value)
            $this->$key=$value;
    }
}

public function __set($name,$value)
{
    $setter=’set’.$name;
    if(method_exists($this,$setter))
        $this->$setter($value);
    else if(strncasecmp($name,’on’,2)===0 && method_exists($this,$name))
    {
        //duplicating getEventHandlers() here for performance
        $name=strtolower($name);
        if(!isset($this->_e[$name]))
            $this->_e[$name]=new CList;
        $this->_e[$name]->add($value);
    }
    else if(method_exists($this,’get’.$name))
        throw new CException(Yii::t(‘yii’,'Property “{class}.{property}” is read only.’,
            array(‘{class}’=>get_class($this), ‘{property}’=>$name)));
    else
        throw new CException(Yii::t(‘yii’,'Property “{class}.{property}” is not defined.’,
            array(‘{class}’=>get_class($this), ‘{property}’=>$name)));
}

public function setImport($aliases)
{
    foreach($aliases as $alias)
        Yii::import($alias);
}

public static function import($alias,$forceInclude=false)
{
    // 先判断$alias是否存在于YiiBase::$_imports[] 中，已存在的直接return， 避免重复import。
    if(isset(self::$_imports[$alias])) // previously imported
        return self::$_imports[$alias];

    // $alias类已定义，记入$_imports[]，直接返回
    if(class_exists($alias,false))
        return self::$_imports[$alias]=$alias;

    // 类似 urlManager 这样的已定义于$_coreClasses[]的类，或不含.的直接类名，记入$_imports[]，直接返回
    if(isset(self::$_coreClasses[$alias]) || ($pos=strrpos($alias,’.'))===false) // a simple class name
    {
        self::$_imports[$alias]=$alias;
        if($forceInclude)
        {
            if(isset(self::$_coreClasses[$alias])) // a core class
                require(YII_PATH.self::$_coreClasses[$alias]);
            else
                require($alias.’.php’);
        }
        return $alias;
    }

    // 产生一个变量 $className，为$alias最后一个.后面的部分
    // 这样的：’x.y.ClassNamer’
    // $className不等于 ‘*’, 并且ClassNamer类已定义的，      ClassNamer’ 记入 $_imports[]，直接返回
    if(($className=(string)substr($alias,$pos+1))!==’*’ && class_exists($className,false))
        return self::$_imports[$alias]=$className;

    // 取得 $alias 里真实的路径部分并且路径有效
    if(($path=self::getPathOfAlias($alias))!==false)
    {
        // $className!==’*'，$className 记入 $_imports[]
        if($className!==’*')
        {
            self::$_imports[$alias]=$className;
            if($forceInclude)
                require($path.’.php’);
            else
                self::$_classes[$className]=$path.’.php’;
            return $className;
        }
        // $alias是’system.web.*’这样的已*结尾的路径，将路径加到include_path中
        else // a directory
        {
            set_include_path(get_include_path().PATH_SEPARATOR.$path);
            return self::$_imports[$alias]=$path;
        }
    }
    else
        throw new CException(Yii::t(‘yii’,'Alias “{alias}” is invalid. Make sure it points to an existing directory or file.’,array(‘{alias}’=>$alias)));
}

public function setComponents($components)
{
    foreach($components as $id=>$component)
    {
        if($component instanceof IApplicationComponent)
            $this->setComponent($id,$component);
        else if(isset($this->_componentConfig[$id]))
            $this->_componentConfig[$id]=CMap::mergeArray($this->_componentConfig[$id],$component);
        else
            $this->_componentConfig[$id]=$component;
    }
}

public function setComponent($id,$component)
{
    $this->_components[$id]=$component;
    if(!$component->getIsInitialized())
        $component->init();
}

public function setParams($value)
{
    $params=$this->getParams();
    foreach($value as $k=>$v)
        $params->add($k,$v);
}

protected function preloadComponents()
{
    foreach($this->preload as $id)
        $this->getComponent($id);
}

public function run()
{
    $this->onBeginRequest(new CEvent($this));
    $this->processRequest();
    $this->onEndRequest(new CEvent($this));
}