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I've tried to google this for a couple of days and I am still pretty confused, so I thought I would try here.

I have an iPhone app that uses Core Data with an sqlite database. I am trying to implement a simple backup/restore of the database with Dropbox.

I downloaded the Dropbox SDK, and I have everything running fine as far as linking, uploading and downloading my .sqlite file.

However, I don't want users to have access to the actual .sqlite file for security purposes. I have been seeing JSON on these boards for some time now so I decided to look into it. I think it is exactly what I need.

Easier said than done. I have never worked with Java and have never implemented anything like JSON before, so I have had to try to figure out where to start.

I understand basically what is going on, but I'm having a heck of a time figuring out how to do it. I think I found a way to get the Core Data model into JSON format (and I do use the term 'think' loosely here). But then what - what exactly do I upload to dropbox? Do I somehow combine the model (in JSON format) and the database? What gets uploaded to Dropbox? I'm sorry if this seems obvious to most, it really is not obvious to me, and I have looked.

I am willing to do the work, but it just seems like I could go in 90 directions without some basic guidance and a start. I am not trying to do anything fancy as far as determining data that has been changed, etc. - just want to backup/restore the whole database. I just need some basic explanation and to be pointed in the right direction. A simple core-data sample project would be tremendous.

I'm not an experienced programmer, but I am a fast learner. Just break it down easy...

Thanks in advance. JPK

Thanks Andrew. I didn't want to 'give away' the database structure of my app, but i can now see that the json string wouldn't be much better than the sqlite file in that area. I am a teach-myself programmer (stay at home mom) so this is all pretty new to me. Maybe I want encryption? But is that allowed for iPhone apps anyway? I recall them asking about encryption when I have uploaded binaries.... I know that iCloud is coming out soon, and I do plan to implement that as well, but with the limited amount of data that can be synced for free, I want to be able to do a simple backup as well. Many of my users have asked for it - a backup in addition to that of iTunes, which really is not a great backup since you can't restore data for just one app (you would have to restore for all apps on the iDevice). Hmmm... Any suggestions as to how to upload the file in such a way that it is not easily readable? Is encryption the way to go in this situation?

Sampson
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SAHM
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  • I was looking at the code Marcus Zarra posted for TouchJSON [link](http://stackoverflow.com/questions/2362323/json-and-core-data-on-the-iphone), but I wasn't sure how those methods should be invoked, and if I need to create an array of my Entities to pass to - (NSArray*)dataStructuresFromManagedObjects:(NSArray*)managedObjects. Do I ultimately upload the jsonString to DropBox? – SAHM Aug 21 '11 at 20:05

2 Answers2

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JPK,

I think you're crossing multiple streams here.

JSON is a data transfer format. IOW, it has almost nothing to do with the architecture of what you are attempting. You will almost certainly use JSON to communicate with Dropbox.

I have a question: why do you think that the user won't have access to any data you send to Dropbox? I suspect that you are probably wrong. The user will have access to everything.

You are doing to an awful lot of work. You already have the .sqlite file being persisted on Dropbox. If you are doing this to make a backup, that data is being backed up in many other venues. In other words, your task is likely moot and unworthy of your time.

I use JSON, REST networks and Core Data daily. If you have a specific question, I am happy to answer it.

Andrew

adonoho
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  • I don't think it's a bad idea, at all, to have the option of backing up app data to Dropbox. However I agree that he's doing a lOT of work converting Core Data to a JSON format, when either way users will be able to read the data... if he's really going to do a backup then do it to Dropbox and accept users will be able to see the database. – Kendall Helmstetter Gelner Aug 23 '11 at 20:12
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Instead of saving the whole database, save out a plist file to Dropbox that you can rebuild a database from. That's assuming you have a lot of extra stuff in your database you do not want the user to see, otherwise just back up the DB as-is if it's all user generated data.

You could also encrypt it but why? Adding encryption only means you have to answer "yes" that you use encryption and may not be able to sell to specific companies, should you choose to encrypt - it's not forbidden.

Kendall Helmstetter Gelner
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