Error handling in the model, or in the controller?

Question

I asked around on various IRC channels but was unable to get an answer with a definitive explanation behind it. Should errors (pertaining to the model, such as transaction failures) be handled in the model, or in the controller?

Thanks in advance for any help.

EDIT

Well, the confusing thing is that my code (in the model) looks something like this already:

try
{
    // Connect to MongoDB
    // Fetch a record
}
catch (MongoConnectionException $e)
{
    // Handle this error
}
catch (MongoException $e)
{
    // Handle this error
}

So, should I return exceptions based on the exceptions MongoDB returns? Or should I directly allow these exceptions to bubble up to the controller?

Thanks!

Answer 1

The correct answer is "Both", but mostly in the Model.

The appropriate thing for your controller to do is simply catch some exception that the model throws, and handle outputting a nice "whups" message. Depending on how you're structuring your models, it might be appropriate for the controller to do some logging.

Anything other than catching the exception, maybe writing to a log (if your model infrastructure doesn't do it), and displaying a pretty error, does not belong in your controller.