CODEWITHSUNDEEP
swiftmacoscocoacore-data
Peter Shaw
Peter Shaw

Reputation: 1907

Is it Possible to put the whole CoreData-Stack in a framework?

I have a very large Project and I am right in a refactoring session. At the beginning my idea sounds good to me, but now i am stuck and confused and near before a git rollback. You guys are my last chance.

We’ve done a GUI application that shows some data that are living in CoreData. A background Process is fetching data from time to time from the network and put them into the CoreData.

So I’ve got the request thing -> pushing into CoreData and <- getting it out onto the GUI. That works for very good for us. It’s straight forward and nothing special. My Company is programming this application since January and the requesting and data part gets huge. We also have a 100% test coverage! \o/. Working in that project could be so nice… if… if the GUI things could be separated. As time goes by I have to split the dev-team into two parts: one for the gui (and the several gui applications that all based on the same data model) The second one for the Request-and-CoreDate part. My Model interface is clean enough to have a nice entry point, so i thought i would be easy to move the Request and CoreData sections into a library-project in my Workspace.

hm, well. no!

I put the Kit.xcdatamodeld into the new library project. I generate all models and add all the code from the main application into the lib. I resolved every problem and start to move the first basic tests into the new project.

I put the managedObjectModel part from our ApplicationDelegate into a DataController in the new project. And changed the first call to use this managedObject from the new class. 

let dc = DataController()
_ = GlobalScope(context: dc.managedObjectContext!)

When I run the first test that should store a simple entity than an error occurs in managedObjectModel:

lazy var managedObjectModel: NSManagedObjectModel = {
    // The managed object model for the application. This property is not optional. It is a fatal error for the application not to be able to find and load its model.
    let modelURL = NSBundle.mainBundle().URLForResource(" <LibName>Kit", withExtension: "momd")!
    return NSManagedObjectModel(contentsOfURL: modelURL)!
}()

enter image description here

fatal error: unexpectedly found nil while unwrapping an Optional value

My Question is: Is it possible to do the whole CoreData stuff into a Framework? I wan’t have any data model or requests in my gui applications? The plan ist to include the framework and use the getXY() setXY() functions of my models. Also the whole network background fetching should be places in the framework. But it seams that there is no mainBundle in a framework. So how to get the database the right way?

Thank you very much. ps

Upvotes: 1

Views: 144

Answers (2)

Lightbow
Lightbow

Reputation: 143

The problem is this line:

let modelURL = NSBundle.mainBundle().URLForResource(" <LibName>Kit", withExtension: "momd")!

It's looking in the main bundle for that resource, which doesn't exist. You'll want to use bundleWithIdentifier or bundleForClass instead, like:

let modelURL = NSBundle(identifier:"com.whatever.yourFrameworkIdentifier").URLForResource...

Upvotes: 1

Marcus S. Zarra
Marcus S. Zarra

Reputation: 46718

First, Core Data is already a framework. You are looking to put your layer on top of Core Data into a framework. Is it possible? Probably, but it is not a great idea.

There is no value in putting a third (or more) of your application into a framework. It will not make anything cleaner or easier. In fact it will make debugging of your application harder.

Separate out the code using groups in Xcode and call it there. Trying to put things into separate Xcode projects (which is what you would need) would lead to more issues than it is worth.

BTW, there is no way to compile the model into the framework as that is an independent file. Therefore your primary application would need to embed the model file anyway.

You could explore creating your own custom CocoaPod like structure but again, it really is not worth it and maintainability will decrease.

Upvotes: 1

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