PHP框架实战（二）：错误和异常的自动处理

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git checkout v0.2

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<?php
class WebApplication {
    // ...

    /**
     * @var boolean Whether to enable error auto-handling, default to true 
     * @since 1.0
     */
    public $enableErrorHandling = true;
    /**
     * @var boolean Whether to enable exception auto-handling, default to true 
     * @since 1.0
     */
    public $enableExceptionHandling = true;
    /**
     * @var callable Error handler 
     * @since 1.0
     */
    public $errorHandler;
    /**
     * @var callable Exception handler 
     * @since 1.0
     */
    public $exceptionHandler;
    /**
     * @var boolean Whether to enable debug mode, default to false 
     * @since 1.0
     */
    public $debug = false;

    /**
     * @param string $config
     */
    public function __construct($config)
    {
        // ...

        $this->initErrorHandlers();
    }

    /**
     * Initialize auto-handling for errors and exceptions
     * @return void
     * @since 1.0
     */
    public function initErrorHandlers()
    {
        if ($this->enableErrorHandling == true)
            set_error_handler(array($this, 'handleError'), error_reporting());
        if ($this->enableExceptionHandling == true)
            set_exception_handler(array($this, 'handleException'));
    }
    
    /**
     * Handle errors
     * @param int $code
     * @param string $message
     * @param string $file
     * @param int $line
     * @return void
     * @since 1.0
     */
    public function handleError($code, $message, $file, $line)
    {
        // prevent recursive errors
        restore_error_handler();
        restore_exception_handler();

        $msg = "Error $code: $message ($file:$line)";
        Flame::error($msg);

        // let errorHandler() return true to prevent displayError()
        if (is_callable($this->errorHandler) && call_user_func($this->errorHandler, $code, $message, $file, $line) !== true)
            $this->displayError($code, $message, $file, $line);

        exit(1);
    }
    
    /**
     * Handle exceptions
     * @param Exception $exception
     * @return void
     * @since 1.0
     */
    public function handleException($exception)
    {
        // prevent recursive errors
        restore_error_handler();
        restore_exception_handler();

        $msg = get_class($exception).': '.$exception->getMessage().' ('.$exception->getFile().':'.$exception->getLine()."\n".$exception->getTraceAsString();
        Flame::error($msg);

        // let exceptionHandler() return true to prevent displayException()
        if (is_callable($this->exceptionHandler) && call_user_func($this->exceptionHandler, $exception) !== true)
            $this->displayException($exception);

        exit(1);
    }
    
    /**
     * Display error information
     * @param int $code
     * @param string $message
     * @param string $file
     * @param int $line
     * @return void
     * @since 1.0
     */
    public function displayError($code, $message, $file, $line)
    {
        if ($this->debug == true) {
            echo "<h1>Error $code</h1>";
            echo "<p>$message in ($file:$line)</p>";
            echo '<pre>';
            debug_print_backtrace();
            echo '</pre>';
        } else {
            echo "<h1>Error $code</h1>";
            echo "<p>$message</p>";
        }
    }
    
    /**
     * Display exception information
     * @param Exception $exception
     * @return void
     * @since 1.0
     */
    public function displayException($exception)
    {
        if ($this->debug == true) {
            echo '<h1>'.get_class($exception).'</h1>';
            echo '<p>'.$exception->getMessage().' ('.$exception->getFile().':'.$exception->getLine().')</p>';
            echo '<pre>'.$exception->getTraceAsString().'</pre>';
        } else {
            echo '<h1>'.get_class($exception).'</h1>';
            echo '<p>'.$exception->getMessage().'</p>';
        }
    }
    
    // ...
}
?>

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<?php
return array(
    // ...
    'exceptionHandler' => function($exception) {
        var_dump($exception);
        return true;
    },
    'errorHandler' => array('MyClass', 'handleError'),
);
?>