本博客要講的是yii整個Application的創(chuàng)建過程，而不是運行過程哈，讀者注意，沒有run啊。 閱讀前須知： web的Application ? ? ? ? ?extends ?yiibaseApplication yiibaseApplication ? ? ?extends ?yiibasemodule yiibasemodule ? ? ? ? ? ?extends ?yiibaseservicelocator yiibaseservicelocator ?extends ?yiibasecomponent yiibasecomponent ? ? ?extends ?yiibasepbject 其中我最關心的 __get ?__set函數是在component類中定義的
1.$config該變量是我們從配置文件加載出來的，一個配置數組的合集（其中的各種require文件就不說了?。?2.Application的創(chuàng)建過程

public?function?__construct($config?=?[])
{

????Yii::$app?=?$this;
????static::setInstance($this);
????$this->state?=?self::STATE_BEGIN;
????$this->preInit($config);
????$this->registerErrorHandler($config);
????Component::__construct($config);
}

解讀setInstance，函數定義如下：

public?static?function?setInstance($instance)
{
????if?($instance?===?null)?{
????????unset(Yii::$app->loadedModules[get_called_class()]);
????}?else?{
????????Yii::$app->loadedModules[get_class($instance)]?=?$instance;
????}
}

現在的loadedModules，我還沒有具體看不知道啥意思，不過對于我這種小白來說，可以暫時忽略 解讀preInit($config)

public?function?preInit(&$config)
{
????if?(!isset($config['id']))?{
????????throw?new?InvalidConfigException('The?"id"?configuration?for?the?Application?is?required.');
????}
????if?(isset($config['basePath']))?{
????????$this->setBasePath($config['basePath']);
????????unset($config['basePath']);
????}?else?{
????????throw?new?InvalidConfigException('The?"basePath"?configuration?for?the?Application?is?required.');
????}

????if?(isset($config['vendorPath']))?{
????????$this->setVendorPath($config['vendorPath']);
????????unset($config['vendorPath']);
????}?else?{
????????//?set?"@vendor"
????????$this->getVendorPath();
????}
????if?(isset($config['runtimePath']))?{
????????$this->setRuntimePath($config['runtimePath']);
????????unset($config['runtimePath']);
????}?else?{
????????//?set?"@runtime"
????????$this->getRuntimePath();
????}

????if?(isset($config['timeZone']))?{
????????$this->setTimeZone($config['timeZone']);
????????unset($config['timeZone']);
????}?elseif?(!ini_get('date.timezone'))?{
????????$this->setTimeZone('UTC');
????}
????//以上除了id，意外，配置文件必須包含?basePath,vendorPath??runtimePath等變量，并將變量放在module類中對應的成員變量中

????//并且設置完成之后進行unset操作

????//?merge?core?components?with?custom?components
????foreach?($this->coreComponents()?as?$id?=>?$component)?{
????????if?(!isset($config['components'][$id]))?{
????????????$config['components'][$id]?=?$component;
????????}?elseif?(is_array($config['components'][$id])?&&?!isset($config['components'][$id]['class']))?{
????????????$config['components'][$id]['class']?=?$component['class'];
????????}
????}
}

需要注意的就是這個coreComponent函數了，這個函數，將web的Application和base的Application的coreComponents返回的數組進行合并操作，也就是說在 整個應用中需要用到的components都需要在webApplication的coreComponents或者其父類的coreComponents中進行定義，并且組件的定義優(yōu)先取用配置文件中的定義 PS:以上這幾步，我們可以認為是進行預整理$config 接下來是registerErrorHandler,這個函數以后會著重看，先按下不表。 看一下Component::__construct的定義，他最終調用的是Yii::Configure

public?static?function?configure($object,?$properties)
{
????foreach?($properties?as?$name?=>?$value)?{

????????$object->$name?=?$value;
????}
????return?$object;
}

接下來，要說的就是這個 ->$name = $value;我們知道這個$object是web下的Application，該類有一個父類是Component，不知道的可以去看，閱讀前須知 該類中定義了注入函數__set

public?function?__set($name,?$value)
{
????$setter?=?'set'?.?$name;
????if?(method_exists($this,?$setter))?{
????????//?set?property
????????$this->$setter($value);
????????return;
????}?elseif?(strncmp($name,?'on?',?3)?===?0)?{
????????//?on?event:?attach?event?handler
????????$this->on(trim(substr($name,?3)),?$value);
????????return;
????}?elseif?(strncmp($name,?'as?',?3)?===?0)?{
????????//?as?behavior:?attach?behavior
????????$name?=?trim(substr($name,?3));
????????$this->attachBehavior($name,?$value?instanceof?Behavior???$value?:?Yii::createObject($value));
????????return;
????}?else?{
????????//?behavior?property
????????$this->ensureBehaviors();
????????foreach?($this->_behaviors?as?$behavior)?{
????????????if?($behavior->canSetProperty($name))?{
????????????????$behavior->$name?=?$value;
????????????????return;
????????????}
????????}
????}
????if?(method_exists($this,?'get'?.?$name))?{
????????throw?new?InvalidCallException('Setting?read-only?property:?'?.?get_class($this)?.?'::'?.?$name);
????}?else?{
????????throw?new?UnknownPropertyException('Setting?unknown?property:?'?.?get_class($this)?.?'::'?.?$name);
????}
}

對于需要組件的會有單獨的處理函數（set.$name函數），我們在配置文件中會定義諸如

return?[
????'components'?=>?[
????????'db'?=>?[
????????????'class'?=>?'yiidbConnection',
????????????'dsn'?=>?'mysql:host=db1-dev.bj1.haodf.net;dbname=test',
????????????'username'?=>?'weihu_dev',
????????????'password'?=>?'hdf@haodf.com',
????????????'charset'?=>?'gbk',
????????],
????????'mailer'?=>?[
????????????'class'?=>?'yiiswiftmailerMailer',
????????????'viewPath'?=>?'@common/mail',
????????????//?send?all?mails?to?a?file?by?default.?You?have?to?set
????????????//?'useFileTransport'?to?false?and?configure?a?transport
????????????//?for?the?mailer?to?send?real?emails.
????????????'useFileTransport'?=>?true,
????????],
????],
];

但是在ServiceLocator中定義了也就是對于配置文件中的components，定義了setComponents函數進行處理

public?function?setComponents($components)
{
????foreach?($components?as?$id?=>?$component)?{
????????$this->set($id,?$component);
????}
}

繼續(xù)分析

public?function?set($id,?$definition)
{
????if?($definition?===?null)?{
????????unset($this->_components[$id],?$this->_definitions[$id]);
????????return;
????}

????unset($this->_components[$id]);

????if?(is_object($definition)?||?is_callable($definition,?true))?{
????????//?an?object,?a?class?name,?or?a?PHP?callable
????????$this->_definitions[$id]?=?$definition;
????}?elseif?(is_array($definition))?{
????????//?a?configuration?array
????????if?(isset($definition['class']))?{
????????????$this->_definitions[$id]?=?$definition;
????????}?else?{
????????????throw?new?InvalidConfigException("The?configuration?for?the?"$id"?component?must?contain?a?"class"?element.");
????????}
????}?else?{
????????throw?new?InvalidConfigException("Unexpected?configuration?type?for?the?"$id"?component:?"?.?gettype($definition));
????}
}

這樣所有Components就會有單獨的_components數組進行統(tǒng)一維護了?。。。。ū热鏳b，比如cache就是在這里進行組成的） 還需要說明的就是除了components意外的其他配置，


可以在配置文件中添加整個應用的事件或者行為而不是單獨針對某個controller的了，其配置如下：

$config['on?test']=['class'=>'test'];