Question

I have a service layer which is responsible for handling exceptions.

The question is, should I be handling exceptions in the service layer and how can I pass an appropriate exception message to a view?

class App_Service_Feed {
  function create() {
    //...
    try {
      $feed->getMapper->insert();
    } catch (Zend_Db_Statement_Exception $e) {
      //what do I return here?        
    } catch (Exception $e) {
      //what do I return here?
    }
  }
}

I’m thinking of returning a response object of some description, so that in my controller I manipulate this.

class App_Controller {
  //...
  $response = $service->create();
  if($response->status) {

  }
}

Alternatively, I’m wondering whether to handle exceptions in the controller…

Answer 1

Even better than the way of jason bourne (yeah):

class App_Service_Feed {
  function create() {
    //...
    try {
      $feed->getMapper->insert();
    } 
    catch (Zend_Db_Statement_Exception $e) 
    {
      throw new App_Service_Feed_Exception("Your own message", NULL, $e);      
    } 
    catch (Exception $e) 
    {
      throw new App_Service_Feed_Exception("Your other message", NULL, $e);
    }
  }
}

Why is this better?

• You are using your own Exception class (extending Zend_Exception). So you can immediately see where the exception was thrown and you can build in your own additional checks, etc.
• You are passing the last exception along to have more history information (trace) about Exception.

The best way to implement Exceptions is to have a hierarchy of extending Exception classes.

App_Exception extends Zend_Exception
App_Service_Exception extends App_Exception
App_Service_Feed_Exception extends App_Service_Exception

So every folder contains an Exception.php. This way you can catch and rethrow Exceptions on every level, if necessary.