Yii分析11：Yii核心组件之异常处理类CErrorHandler

Yii分析11：Yii核心组件之错误处理类CErrorHandler

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类如其名，CErrorHandler在Yii中主要的功能就是处理未捕获的错误和异常，它使用两种视图：开发视图和生产视图，以区分不同的部署环境。

与CDbConnection一样，CErrorHandler也是CApplication的一个核心组件，在创建应用程序时，作为应用程序的一个内部示例自动初始化，CErrorHandler没有定义自己的init函数，因此使用的是父类的初始化。

在创建应用程序实例时，会调用PHP的错误和异常注册函数来指定使用系统自定义的错误处理类来处理错误和异常：

CApplication:

abstract class CApplication extends CModulepublic function __construct($config=null){……//初始化系统处理函数$this->initSystemHandlers();$this->registerCoreComponents();……}protected function initSystemHandlers(){if(YII_ENABLE_EXCEPTION_HANDLER)//设置异常处理函数set_exception_handler(array($this,'handleException'));if(YII_ENABLE_ERROR_HANDLER)//设置错误处理函数set_error_handler(array($this,'handleError'),error_reporting());}//错误处理函数public function handleError($code,$message,$file,$line){if($code & error_reporting()){// disable error capturing to avoid recursive errorsrestore_error_handler();restore_exception_handler();$log="$message ($file:$line)\nStack trace:\n";$trace=debug_backtrace();// skip the first 3 stacks as they do not tell the error positionif(count($trace)>3)$trace=array_slice($trace,3);foreach($trace as $i=>$t){if(!isset($t['file']))$t['file']='unknown';if(!isset($t['line']))$t['line']=0;if(!isset($t['function']))$t['function']='unknown';$log.="#$i {$t['file']}({$t['line']}): ";if(isset($t['object']) && is_object($t['object']))$log.=get_class($t['object']).'->';$log.="{$t['function']}()\n";}if(isset($_SERVER['REQUEST_URI']))$log.='REQUEST_URI='.$_SERVER['REQUEST_URI'];Yii::log($log,CLogger::LEVEL_ERROR,'php');try{Yii::import('CErrorEvent',true);$event=new CErrorEvent($this,$code,$message,$file,$line);$this->onError($event);if(!$event->handled){// try an error handler//如果注册了错误处理类，使用错误处理类来处理，否则直接显示错误if(($handler=$this->getErrorHandler())!==null)$handler->handle($event);else$this->displayError($code,$message,$file,$line);}}catch(Exception $e){$this->displayException($e);}try{$this->end(1);}catch(Exception $e){// use the most primitive way to log error$msg = get_class($e).': '.$e->getMessage().' ('.$e->getFile().':'.$e->getLine().")\n";$msg .= $e->getTraceAsString()."\n";$msg .= "Previous error:\n";$msg .= $log."\n";$msg .= '$_SERVER='.var_export($_SERVER,true);error_log($msg);exit(1);}}}//异常处理函数public function handleException($exception){// disable error capturing to avoid recursive errorsrestore_error_handler();restore_exception_handler();$category='exception.'.get_class($exception);if($exception instanceof CHttpException)$category.='.'.$exception->statusCode;// php <5.2 doesn't support string conversion auto-magically$message=$exception->__toString();if(isset($_SERVER['REQUEST_URI']))$message.=' REQUEST_URI='.$_SERVER['REQUEST_URI'];Yii::log($message,CLogger::LEVEL_ERROR,$category);try{$event=new CExceptionEvent($this,$exception);$this->onException($event);if(!$event->handled){// try an error handlerif(($handler=$this->getErrorHandler())!==null)$handler->handle($event);else$this->displayException($exception);}}catch(Exception $e){$this->displayException($e);}try{$this->end(1);}catch(Exception $e){// use the most primitive way to log error$msg = get_class($e).': '.$e->getMessage().' ('.$e->getFile().':'.$e->getLine().")\n";$msg .= $e->getTraceAsString()."\n";$msg .= "Previous exception:\n";$msg .= get_class($exception).': '.$exception->getMessage().' ('.$exception->getFile().':'.$exception->getLine().")\n";$msg .= $exception->getTraceAsString()."\n";$msg .= '$_SERVER='.var_export($_SERVER,true);error_log($msg);exit(1);}}