Yii: Catching all exceptions for a specific controller

Question

I am working on a project which includes a REST API component. I have a controller dedicated to handling all of the REST API calls.

Is there any way to catch all exceptions for that specific controller so that I can take a different action for those exceptions than the rest of the application's controllers?

IE: I'd like to respond with either an XML/JSON formatted API response that contains the exception message, rather than the default system view/stack trace (which isn't really useful in an API context). Would prefer not having to wrap every method call in the controller in its own try/catch.

Thanks for any advice in advance.

Answer 1

You can completely bypass Yii's default error displaying mechanism by registering onError and onException event listeners.

Example:

class ApiController extends CController
{
  public function init()
  {
    parent::init();

    Yii::app()->attachEventHandler('onError',array($this,'handleError'));
    Yii::app()->attachEventHandler('onException',array($this,'handleError'));
  }

  public function handleError(CEvent $event)
  {        
    if ($event instanceof CExceptionEvent)
    {
      // handle exception
      // ...
    }
    elseif($event instanceof CErrorEvent)
    {
      // handle error
      // ...
    }

    $event->handled = TRUE;
  }

  // ...
}

Answer 2

I wasn't able to attach events in controller, and I did it by redefinition CWebApplication class:

class WebApplication extends CWebApplication
{
protected function init()
{
    parent::init();

    Yii::app()->attachEventHandler('onError',array($this, 'handleApiError'));
    Yii::app()->attachEventHandler('onException',array($this, 'handleApiError'));
}

/**
 * Error handler
 * @param CEvent $event
 */
public function handleApiError(CEvent $event)
{
    $statusCode = 500;

    if($event instanceof CExceptionEvent)
    {
        $statusCode = $event->exception->statusCode;
        $body = array(
            'code' => $event->exception->getCode(),
            'message' => $event->exception->getMessage(),
            'file' => YII_DEBUG ? $event->exception->getFile() : '*',
            'line' => YII_DEBUG ? $event->exception->getLine() : '*'
        );
    }
    else
    {
        $body = array(
            'code' => $event->code,
            'message' => $event->message,
            'file' => YII_DEBUG ? $event->file : '*',
            'line' => YII_DEBUG ? $event->line : '*'
        );
    }

    $event->handled = true;

    ApiHelper::instance()->sendResponse($statusCode, $body);
}
}

In index.php:

require_once(dirname(__FILE__) . '/protected/components/WebApplication.php');
Yii::createApplication('WebApplication', $config)->run();