Parse Helpers for iOS

Parse (parse.com) is a great alternative to creating your own service for storage of data, but I ran into some issues with the Parse iOS SDK. Mostly dealing with creating, updating and deleting of PFObjects while offline. There's obviously more than one way to solve this, and I got lots of inspiration from the interwebs. Figured I'd share my solution in hopes it could help out someone else.

PFObject can't be subclassed, so I created a category with a few utility methods and some methods for creating and syncing objects.

When offline, I store any updates or new entries using CoreData. You can see the data structure and methods creating and fetching stored objects in the UnsyncedObjects class. Since you can't just store a PFObject 'as is' in a persistent store, I also created a value transformer for it. (Note how I deal with several user accounts in same app here and in the UnsyncedObject class).

In the app delegate, you'll see how I sync the data with the server when back online.

I tried to use the PFQueryTableViewController, but I couldn't since the objects property (the list of PFObjects returned when the controller runs it's queryForTable) is readonly. The LogViewController is a UITableViewController subclass, and it has a method called syncWithUnsavedData that 'mixes' the cached objects and the objects that are in the persistent store. It's a little messy, but it works...

The TripViewController deals with creating new and updating existing objects while offline.