diff --git a/framework/yii/YiiBase.php b/framework/yii/YiiBase.php
index ee75822..61208dc 100644
--- a/framework/yii/YiiBase.php
+++ b/framework/yii/YiiBase.php
@@ -6,6 +6,7 @@
  */
 namespace yii;
 
+use yii\base\Arrayable;
 use yii\base\Exception;
 use yii\base\InvalidConfigException;
 use yii\base\InvalidParamException;
@@ -636,6 +637,31 @@ class YiiBase
 	{
 		return get_object_vars($object);
 	}
+
+	/**
+	 * Converts the object into an array.
+	 * @param object|array $object the object to be converted into an array
+	 * @param boolean $recursive whether to recursively converts properties which are objects into arrays.
+	 * @return array the array representation of the object
+	 */
+	public static function toArray($object, $recursive = true)
+	{
+		if ($object instanceof Arrayable) {
+			$object = $object->toArray();
+			if (!$recursive) {
+				return $object;
+			}
+		}
+		$result = array();
+		foreach ($object as $key => $value) {
+			if ($recursive && (is_array($value) || is_object($value))) {
+				$result[$key] = static::toArray($value, true);
+			} else {
+				$result[$key] = $value;
+			}
+		}
+		return $result;
+	}
 }
 
 YiiBase::$aliases = array(
diff --git a/framework/yii/base/Application.php b/framework/yii/base/Application.php
index 0f78cb6..b1a7750 100644
--- a/framework/yii/base/Application.php
+++ b/framework/yii/base/Application.php
@@ -19,10 +19,6 @@ use yii\web\HttpException;
 abstract class Application extends Module
 {
 	/**
-	 * @event ResponseEvent an event that is triggered after [[handle()]] returns a response.
-	 */
-	const EVENT_RESPONSE = 'response';
-	/**
 	 * @var string the application name.
 	 */
 	public $name = 'My Application';
@@ -144,11 +140,7 @@ abstract class Application extends Module
 	public function run()
 	{
 		$response = $this->handle($this->getRequest());
-
-		$event = new ResponseEvent($response);
-		$this->trigger(self::EVENT_RESPONSE, $event);
-		$event->response->send();
-
+		$response->send();
 		return $response->exitStatus;
 	}
 
@@ -422,18 +414,19 @@ abstract class Application extends Module
 	 */
 	public function handleFatalError()
 	{
+		// load ErrorException manually here because autoloading them will not work
+		// when error occurs while autoloading a class
+		if (!class_exists('\\yii\\base\\Exception', false)) {
+			require_once(__DIR__ . '/Exception.php');
+		}
+		if (!class_exists('\\yii\\base\\ErrorException', false)) {
+			require_once(__DIR__ . '/ErrorException.php');
+		}
+
 		$error = error_get_last();
 
 		if (ErrorException::isFatalError($error)) {
 			unset($this->_memoryReserve);
-			// load ErrorException manually here because autoloading them will not work
-			// when error occurs while autoloading a class
-			if (!class_exists('\\yii\\base\\Exception', false)) {
-				require_once(__DIR__ . '/Exception.php');
-			}
-			if (!class_exists('\\yii\\base\\ErrorException', false)) {
-				require_once(__DIR__ . '/ErrorException.php');
-			}
 			$exception = new ErrorException($error['message'], $error['type'], $error['type'], $error['file'], $error['line']);
 			// use error_log because it's too late to use Yii log
 			error_log($exception);
diff --git a/framework/yii/base/Jsonable.php b/framework/yii/base/Arrayable.php
similarity index 51%
rename from framework/yii/base/Jsonable.php
rename to framework/yii/base/Arrayable.php
index e9425a6..1822e51 100644
--- a/framework/yii/base/Jsonable.php
+++ b/framework/yii/base/Arrayable.php
@@ -8,15 +8,16 @@
 namespace yii\base;
 
 /**
- * Jsonable should be implemented by classes that need to be represented in JSON format.
+ * Arrayable should be implemented by classes that need to be represented in array format.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-interface Jsonable
+interface Arrayable
 {
 	/**
-	 * @return string the JSON representation of this object
+	 * Converts the object into an array.
+	 * @return array the array representation of this object
 	 */
-	public function toJson();
+	public function toArray();
 }
diff --git a/framework/yii/base/ErrorHandler.php b/framework/yii/base/ErrorHandler.php
index e9ca91e..1e6671b 100644
--- a/framework/yii/base/ErrorHandler.php
+++ b/framework/yii/base/ErrorHandler.php
@@ -9,7 +9,6 @@ namespace yii\base;
 
 use Yii;
 use yii\web\HttpException;
-use yii\web\Response;
 
 /**
  * ErrorHandler handles uncaught PHP errors and exceptions.
@@ -90,31 +89,41 @@ class ErrorHandler extends Component
 
 		$useErrorView = !YII_DEBUG || $exception instanceof UserException;
 
+		$response = Yii::$app->getResponse();
 		if ($useErrorView && $this->errorAction !== null) {
 			$result = Yii::$app->runAction($this->errorAction);
 			if ($result instanceof Response) {
 				$response = $result;
 			} else {
-				$response = new Response;
-				$response->content = $result;
+				$response->setContent($result);
 			}
-		} else {
-			$response = new Response;
+		} elseif ($response->format === \yii\web\Response::FORMAT_HTML) {
 			if (isset($_SERVER['HTTP_X_REQUESTED_WITH']) && $_SERVER['HTTP_X_REQUESTED_WITH'] === 'XMLHttpRequest') {
 				// AJAX request
-				$response->content = Yii::$app->renderException($exception);
+				$response->setContent(Yii::$app->renderException($exception));
 			} else {
 				// if there is an error during error rendering it's useful to
 				// display PHP error in debug mode instead of a blank screen
 				if (YII_DEBUG) {
 					ini_set('display_errors', 1);
 				}
-
 				$file = $useErrorView ? $this->errorView : $this->exceptionView;
-				$response->content = $this->renderFile($file, array(
+				$response->setContent($this->renderFile($file, array(
 					'exception' => $exception,
-				));
+				)));
+			}
+		} else {
+			if ($exception instanceof Exception) {
+				$content = $exception->toArray();
+			} else {
+				$content = array(
+					'type' => get_class($exception),
+					'name' => 'Exception',
+					'message' => $exception->getMessage(),
+					'code' => $exception->getCode(),
+				);
 			}
+			$response->setContent($content);
 		}
 
 		if ($exception instanceof HttpException) {
diff --git a/framework/yii/base/Exception.php b/framework/yii/base/Exception.php
index 956f17b..fe497a7 100644
--- a/framework/yii/base/Exception.php
+++ b/framework/yii/base/Exception.php
@@ -13,7 +13,7 @@ namespace yii\base;
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Exception extends \Exception
+class Exception extends \Exception implements Arrayable
 {
 	/**
 	 * @return string the user-friendly name of this exception
@@ -22,4 +22,18 @@ class Exception extends \Exception
 	{
 		return \Yii::t('yii', 'Exception');
 	}
+
+	/**
+	 * Returns the array representation of this object.
+	 * @return array the array representation of this object.
+	 */
+	public function toArray()
+	{
+		return array(
+			'type' => get_class($this),
+			'name' => $this->getName(),
+			'message' => $this->getMessage(),
+			'code' => $this->getCode(),
+		);
+	}
 }
diff --git a/framework/yii/base/Model.php b/framework/yii/base/Model.php
index b9b7d2d..9a3e08d 100644
--- a/framework/yii/base/Model.php
+++ b/framework/yii/base/Model.php
@@ -7,10 +7,10 @@
 
 namespace yii\base;
 
+use Yii;
 use ArrayObject;
 use ArrayIterator;
 use yii\helpers\Inflector;
-use yii\helpers\Json;
 use yii\validators\RequiredValidator;
 use yii\validators\Validator;
 
@@ -42,7 +42,7 @@ use yii\validators\Validator;
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Model extends Component implements \IteratorAggregate, \ArrayAccess, Jsonable
+class Model extends Component implements \IteratorAggregate, \ArrayAccess
 {
 	/**
 	 * @event ModelEvent an event raised at the beginning of [[validate()]]. You may set
@@ -639,13 +639,13 @@ class Model extends Component implements \IteratorAggregate, \ArrayAccess, Jsona
 	}
 
 	/**
-	 * Returns the JSON representation of this object.
+	 * Converts the object into an array.
 	 * The default implementation will return [[attributes]].
-	 * @return string the JSON representation of this object.
+	 * @return array the array representation of the object
 	 */
-	public function toJson()
+	public function toArray()
 	{
-		return Json::encode($this->getAttributes());
+		return $this->getAttributes();
 	}
 
 	/**
diff --git a/framework/yii/base/Object.php b/framework/yii/base/Object.php
index 79c1f7b..946be85 100644
--- a/framework/yii/base/Object.php
+++ b/framework/yii/base/Object.php
@@ -8,14 +8,13 @@
 namespace yii\base;
 
 use Yii;
-use yii\helpers\Json;
 
 /**
  * @include @yii/base/Object.md
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class Object implements Jsonable
+class Object implements Arrayable
 {
 	/**
 	 * @return string the fully qualified name of this class.
@@ -221,12 +220,13 @@ class Object implements Jsonable
 	}
 
 	/**
-	 * Returns the JSON representation of this object.
-	 * The default implementation will return all public member variables.
-	 * @return string the JSON representation of this object.
+	 * Converts the object into an array.
+	 * The default implementation will return all public property values as an array.
+	 * However, if the object is traversable, it will return the data obtained by the data iteration.
+	 * @return array the array representation of the object
 	 */
-	public function toJson()
+	public function toArray()
 	{
-		return Json::encode(Yii::getObjectVars($this));
+		return Yii::toArray($this, false);
 	}
 }
diff --git a/framework/yii/base/Response.php b/framework/yii/base/Response.php
index 83fef93..886774f 100644
--- a/framework/yii/base/Response.php
+++ b/framework/yii/base/Response.php
@@ -14,12 +14,24 @@ namespace yii\base;
 class Response extends Component
 {
 	/**
+	 * @event ResponseEvent an event that is triggered by [[send()]] before it sends the response to client.
+	 * You may respond to this event to modify the response before it is sent out.
+	 */
+	const EVENT_SEND = 'send';
+
+	/**
 	 * @var integer the exit status. Exit statuses should be in the range 0 to 254.
 	 * The status 0 means the program terminates successfully.
 	 */
 	public $exitStatus = 0;
 
+	/**
+	 * Sends the response to client.
+	 * This method will trigger the [[EVENT_SEND]] event. Please make sure you call
+	 * the parent implementation first if you override this method.
+	 */
 	public function send()
 	{
+		$this->trigger(self::EVENT_SEND, new ResponseEvent($this));
 	}
 }
diff --git a/framework/yii/helpers/base/Json.php b/framework/yii/helpers/base/Json.php
index 41d5bf0..2d95017 100644
--- a/framework/yii/helpers/base/Json.php
+++ b/framework/yii/helpers/base/Json.php
@@ -8,7 +8,7 @@
 namespace yii\helpers\base;
 
 use yii\base\InvalidParamException;
-use yii\base\Jsonable;
+use yii\base\Arrayable;
 use yii\web\JsExpression;
 
 /**
@@ -91,9 +91,8 @@ class Json
 				$token = '!{[' . count($expressions) . ']}!';
 				$expressions['"' . $token . '"'] = $data->expression;
 				return $token;
-			} elseif ($data instanceof Jsonable) {
-				return $data->toJson();
 			} else {
+				$data = $data instanceof Arrayable ? $data->toArray() : get_object_vars($data);
 				$result = array();
 				foreach ($data as $key => $value) {
 					if (is_array($value) || is_object($value)) {
diff --git a/framework/yii/web/Application.php b/framework/yii/web/Application.php
index 54df2a7..aa03a46 100644
--- a/framework/yii/web/Application.php
+++ b/framework/yii/web/Application.php
@@ -71,7 +71,9 @@ class Application extends \yii\base\Application
 				return $result;
 			} else {
 				$response = $this->getResponse();
-				$response->content = $result;
+				if ($result !== null) {
+					$response->setContent($result);
+				}
 				return $response;
 			}
 		} catch (InvalidRouteException $e) {
diff --git a/framework/yii/web/HttpException.php b/framework/yii/web/HttpException.php
index 384a5b4..c0a23db 100644
--- a/framework/yii/web/HttpException.php
+++ b/framework/yii/web/HttpException.php
@@ -51,4 +51,15 @@ class HttpException extends UserException
 			return 'Error';
 		}
 	}
+
+	/**
+	 * Returns the array representation of this object.
+	 * @return array the array representation of this object.
+	 */
+	public function toArray()
+	{
+		$array = parent::toArray();
+		$array['status'] = $this->statusCode;
+		return $array;
+	}
 }
diff --git a/framework/yii/web/Response.php b/framework/yii/web/Response.php
index 696aa1b..32a0f85 100644
--- a/framework/yii/web/Response.php
+++ b/framework/yii/web/Response.php
@@ -8,6 +8,7 @@
 namespace yii\web;
 
 use Yii;
+use yii\base\InvalidConfigException;
 use yii\web\HttpException;
 use yii\base\InvalidParamException;
 use yii\helpers\FileHelper;
@@ -23,6 +24,21 @@ use yii\helpers\StringHelper;
  */
 class Response extends \yii\base\Response
 {
+	const FORMAT_RAW = 'raw';
+	const FORMAT_HTML = 'html';
+	const FORMAT_JSON = 'json';
+	const FORMAT_JSONP = 'jsonp';
+	const FORMAT_XML = 'xml';
+
+	/**
+	 * @var string the response format.
+	 */
+	public $format = self::FORMAT_HTML;
+	/**
+	 * @var string the charset of the text response. If not set, it will use
+	 * the value of [[Application::charset]].
+	 */
+	public $charset;
 	/**
 	 * @var integer the HTTP status code that should be used when redirecting in AJAX mode.
 	 * This is used by [[redirect()]]. A 2xx code should normally be used for this purpose
@@ -33,10 +49,6 @@ class Response extends \yii\base\Response
 	/**
 	 * @var string
 	 */
-	public $content;
-	/**
-	 * @var string
-	 */
 	public $statusText;
 	/**
 	 * @var string the version of the HTTP protocol to use. If not set, it will be determined via `$_SERVER['SERVER_PROTOCOL']`,
@@ -133,6 +145,9 @@ class Response extends \yii\base\Response
 				$this->version = '1.1';
 			}
 		}
+		if ($this->charset === null) {
+			$this->charset = Yii::$app->charset;
+		}
 	}
 
 	/**
@@ -172,7 +187,7 @@ class Response extends \yii\base\Response
 	public function renderJson($data)
 	{
 		$this->getHeaders()->set('Content-Type', 'application/json');
-		$this->content = Json::encode($data);
+		$this->setContent(Json::encode($data));
 		$this->send();
 	}
 
@@ -180,16 +195,16 @@ class Response extends \yii\base\Response
 	{
 		$this->getHeaders()->set('Content-Type', 'text/javascript');
 		$data = Json::encode($data);
-		$this->content = "$callbackName($data);";
+		$this->setContent("$callbackName($data);");
 		$this->send();
 	}
 
 	/**
 	 * Sends the response to the client.
-	 * @return boolean true if the response was sent
 	 */
 	public function send()
 	{
+		parent::send();
 		$this->sendHeaders();
 		$this->sendContent();
 		$this->clear();
@@ -199,8 +214,8 @@ class Response extends \yii\base\Response
 	{
 		$this->_headers = null;
 		$this->_statusCode = null;
+		$this->_content = null;
 		$this->statusText = null;
-		$this->content = null;
 	}
 
 	/**
@@ -253,7 +268,7 @@ class Response extends \yii\base\Response
 	 */
 	protected function sendContent()
 	{
-		echo $this->content;
+		echo $this->getContent();
 	}
 
 	/**
@@ -304,10 +319,10 @@ class Response extends \yii\base\Response
 		if ($begin !=0 || $end != $contentLength - 1) {
 			$this->setStatusCode(206);
 			$headers->set('Content-Range', "bytes $begin-$end/$contentLength");
-			$this->content = StringHelper::substr($content, $begin, $end - $begin + 1);
+			$this->setContent(StringHelper::substr($content, $begin, $end - $begin + 1), self::FORMAT_RAW);
 		} else {
 			$this->setStatusCode(200);
-			$this->content = $content;
+			$this->setContent($content, self::FORMAT_RAW);
 		}
 
 		$this->send();
@@ -628,4 +643,44 @@ class Response extends \yii\base\Response
 	{
 		return in_array($this->getStatusCode(), array(201, 204, 304));
 	}
+
+	private $_content;
+
+	public function getContent()
+	{
+		return $this->_content;
+	}
+
+	public function setContent($value, $format = null)
+	{
+		if ($format !== null) {
+			$this->format = $format;
+		}
+		$this->_content = $this->formatContent($value, $format);
+	}
+
+	protected function formatContent($data, $format)
+	{
+		switch ($this->format) {
+			case self::FORMAT_RAW:
+				return $data;
+			case self::FORMAT_HTML:
+				$this->getHeaders()->setDefault('Content-Type', 'text/html; charset=' . $this->charset);
+				return $data;
+			case self::FORMAT_JSON:
+				$this->getHeaders()->set('Content-Type', 'application/json');
+				return Json::encode($data);
+			case self::FORMAT_JSONP:
+				$this->getHeaders()->set('Content-Type', 'text/javascript');
+				if (is_array($data) && isset($data['data'], $data['callback'])) {
+					return sprintf('%s(%s);', $data['callback'], Json::encode($data['data']));
+				} else {
+					throw new InvalidParamException("The 'jsonp' response requires that the data be an array consisting of both 'data' and 'callback' elements.");
+				}
+			case self::FORMAT_XML:
+				// todo
+			default:
+				throw new InvalidConfigException("Unsupported response format: $format");
+		}
+	}
 }