TICoreDataSync behavior and functionality related questions

[ghulammustafa]

These are not issues, but rather questions. I wasn't sure where to post these. I'd appreciate if you can find sometime to address these. Thanking in anticipation.

• Does iCloud deprecates TICoreDataSync? (I'm asking because ZSync was deprecated by Marcus Zarra after the introduction of iCloud by Apple. Reference: https://github.com/mzarra/ZSync) What's your thoughts on iCloud, and what are the advantages and disadvantages of using TICoreDataSync instead of iCloud?
• Does TICoreDataSync support "Core Data Model Versioning and Data Migration"?
• Does TICoreDataSync support manual conflict resolution? Yes. Use TICDSDocumentSyncManagerDelegate.
• Does TICoreDataSync support deleting the files on remote server and starting from scratch?
• Does TICoreDataSync support notifications, for the case when data on the remote server changes?
• Does TICoreDataSync support "ordered" relationship (NSOrderedSet)? For reference, see Core Data Release Notes for OS X v10.7 and iOS 5.0 here: http://developer.apple.com/library/mac/#releasenotes/DataManagement/RN-CoreData/_index.html.
• Does TICoreDataSync support advanced "Store in External Record File" for Core-Data entity attribute (setAllowsExternalBinaryDataStorage:)? For reference, see Core Data Release Notes for OS X v10.7 and iOS 5.0 here: http://developer.apple.com/library/mac/#releasenotes/DataManagement/RN-CoreData/_index.html.
• How does TICoreDataSync respond if the application is removed from Device A, and then it's reinstalled? Does it automatically pull all the data from the Dropbox, and uses the same UUID for the device? Or will it create a new UUID for the device?
• Are there any known issues? Other than the ones that are in the "Issues" section of the Github page.
• Are you aware of any production iOS applications that are using TICoreDataSync? Knowing that applications similar to the one that I'm planning are using TICoreDataSync will give me some confidence.

Thanks.

[MrRooni]

No worries, I'll take them one by one:

• Does iCloud deprecates TICoreDataSync? (I'm asking because ZSync was deprecated by Marcus Zarra after the introduction of iCloud by Apple. Reference: https://github.com/mzarra/ZSync) What's your thoughts on iCloud, and what are the advantages and disadvantages of using TICoreDataSync instead of iCloud?

No, iCloud does not deprecate TICDS. iCloud has its strengths in certain types of sync, but has shown to struggle with Core Data syncing. For more on the ins and outs of Core Data over iCloud I suggest looking through Drew's blog here: http://mentalfaculty.tumblr.com

Ancillary to those posts, Drew was recently successful in implementing TICDS using iCloud as the storage medium, showing that the two are not mutually exclusive.

• Does TICoreDataSync support "Core Data Model Versioning and Data Migration"?

The short answer is, "no, not fully", but there is a long answer. TICDS supports model versioning and data up to a point. That is, if the changes to the model are minimal enough TICDS will continue to sync two different model versions. For instance, if you are syncing entities called 'A' with attributes 'one' and 'two' and then you augment your data model down the road by adding attributes 'three' and 'four' you can continue to sync change to A.one and A.two across different model versions. However, if you attempt to sync changes to A.three with an instance of the old data model the app will most likely crash because that key doesn't exist.

• Does TICoreDataSync support manual conflict resolution? Yes. Use TICDSDocumentSyncManagerDelegate.
• Does TICoreDataSync support deleting the files on remote server and starting from scratch?

It does. Once you have a registered TICDSApplicationSyncManager you can tell it to removeAllSyncDataFromRemote.

• Does TICoreDataSync support notifications, for the case when data on the remote server changes?

Yes, there are delegate callbacks to notify you that the data on the server has been wiped by another client or if the data is in a state that the framework cannot understand.

• Does TICoreDataSync support "ordered" relationship (NSOrderedSet)? For reference, see Core Data Release Notes for OS X v10.7 and iOS 5.0 here: http://developer.apple.com/library/mac/#releasenotes/DataManagement/RN-CoreData/_index.html.

I haven't tried any syncing with ordered relationships, but given the quick look at the documentation it would appear that we might need to add some support to the framework to get it to work with ordered relationships. I'd love to see a test app using ordered relationships to verify this though.

• Does TICoreDataSync support advanced "Store in External Record File" for Core-Data entity attribute (setAllowsExternalBinaryDataStorage:)? For reference, see Core Data Release Notes for OS X v10.7 and iOS 5.0 here: http://developer.apple.com/library/mac/#releasenotes/DataManagement/RN-CoreData/_index.html.

No, TICDS does not currently support externally stored data.

• How does TICoreDataSync respond if the application is removed from Device A, and then it's reinstalled? Does it automatically pull all the data from the Dropbox, and uses the same UUID for the device? Or will it create a new UUID for the device?

If the application is removed from the device and reinstalled TICDS will set it up as a new device with new unique ID.

• Are there any known issues? Other than the ones that are in the "Issues" section of the Github page.

We've had some issues with undo/redo and their changes not being picked up by TICDS. There is also a known issue that if the user attempts to sync a large number of change sets at one time TICDS will run out of memory and the app will crash.

• Are you aware of any production iOS applications that are using TICoreDataSync? Knowing that applications similar to the one that I'm planning are using TICoreDataSync will give me some confidence.

TICDS is currently shipping with MoneyWell for Mac and MoneyWell for iPhone. (http://nothirst.com/moneywell/ and http://nothirst.com/moneywell/iphone)

Hope this helps!

[ghulammustafa]

Thank you for taking the time to address these questions. I really appreciate it.

I did check Drew's blog as well as other resources (including Aleksey Novicov's iCloud Store Manager class). Drew's blog is a great resource. It was nice to learn that he successfully implemented TICDS with iCloud. I would love to see the support for iCloud in TICDS (or a Tutorial on How To do it).

I just have a few related questions:

• Are you planning to post an update with support for some of the items mentioned above i.e. support for externally stored data and enhanced support for "Core Data Model Versioning and Data Migration"?
• How can I go about using TICoreDataSync to sync associated external files like Images? Will I have to do it myself using Dropbox API?

Best Regards, Mustafa

[MrRooni]

Mustafa,

We have a long term goal to allow syncing external dependencies since MoneyWell currently allows a user to attach a receipt image to their transactions. That image file is not stored in our database, just a reference to it. We don't, however, have a timeline for adding this feature to the framework. If someone in the community were to add it themselves and then submit a pull request I'd be more than happy to incorporate it into the framework. (wink wink, nudge nudge)

Cheers, Michael