php symfony exception handling/error handling

Question

Working on a symfony application that uses nusoap (is this the best method for integrating soap work with php/symfony?) for taking credit card payments.

I've simplified an example of my code below.

What I'm struggling with is the best way to handle exceptions. The example below only has 1 custom exception (where should my custom exceptions reside within the directory structure of symfony? (lib/exception?)) But what happens when there are several different types of exceptions that handle a specific error? It's not very elegant to have a try/catch block with 20 odd exceptions.

I'm also not sure of where I should be throwing and catching. I need to set some user flashes to alert the user of any problems, so I figure the catching should be done in the actions controller rather than within the class that handles the soap call.

Could anyone please advise where I might be going wrong?

I hate messy code/solutions and want to stick to the DRY principle as much as possible. I think I might also be missing some built in symfony functionality that might help with this but whenever I search I usually find examples that are for symfony 1.2, I'm using 1.4.

Some examples would be great, thanks.

lib/soap_payment.class.php

class SoapPayment
{
  public function charge()
  {
    /*assume options are setup correctly for sake of example*/
    try
    {
      $this->call();
    }
    catch (SoapPaymentClientFaultException $e)
    {
      /* should this be caught here? */
    }
  }

  private function call()
  {
    $this->client->call($this->options);

    if ($this->client->hasFault())
    {
      throw new SoapPaymentClientFaultException();
    }
  }
}

apps/frontend/payment/actions/actions.class.php

class paymentActions extends sfActions
{
   public function executeCreate(sfWebRequest $request)
   {
     /* check form is valid etc */

     $soap_payment = new SoapPayment();

     try
     {
       $soap_payment->charge();
     }
     catch (SoapPaymentClientFaultException $e)
     {
       /* or throw/catch here? */
       $this->getUser()->setFlash('error', ...);

       $this->getLogger()->err(...);
     }   

     /* save form regardless, will set a flag to check if successful or not in try/catch block */
   }
}

Answer 1

One not very well known feature of Symfony is that exceptions can manage the content sent in a response. So you could do something like this:

class SoapException extends sfException
{
  public function printStackTrace() //called by sfFrontWebController when an sfException is thrown
  {
    $response = sfContext::getInstance()->getResponse();
    if (null === $response)
    {
      $response = new sfWebResponse(sfContext::getInstance()->getEventDispatcher());
      sfContext::getInstance()->setResponse($response);
    }

    $response->setStatusCode(5xx);
    $response->setContent('oh noes'); //probably you want a whole template here that prints the message that was a part of the SoapException
  }
}

If you need a cleaner handling of SOAP exceptions, like setting flashes, etc. you'll probably have to catch each exception. One idea here might be to create a generic SoapException class that is extended by more specific SoapExceptions so you don't have to catch a bunch of different types. The above code may be a useful fallback mechanism as well.

Finally, yes, you should place custom exceptions in lib/exception.