Htykuut

How do I handle fetching objects for a social timeline with core data?

Right now, every Post object returned from a network request is saved to core data. So, when a random user's profile is loaded, their posts are saved, which means they appear in the current user's timeline (even if they aren't followed by the current user).

My timeline, an NSFetchedResultsController pulls in all the saved posts, including those created by users the current user doesn't follow.

Should I only save posts that belong in the timeline to core data?

Or is there a way to store the timeline's list of core data objects to another location?

Here is my current setup:

@objc(Post)

public class Post: NSManagedObject {



    static func findOrCreatePost(id: String, data: [String:Any], in context: NSManagedObjectContext) -> Post {

        let request: NSFetchRequest<Post> = Post.fetchRequest()

        if let id = data["_id"] as? String {

            request.predicate = NSPredicate(format: "id = %@", id)

        }

        do {

            let matches = try context.fetch(request)

            if matches.count > 0 {

                return matches[0]

            }

        } catch {

            let error = error

            print(error.localizedDescription)

        }

        let post = Post(context: context)

        post.id = id

        status.text = data["text"] as? String

        ...

        PersistenceService.saveContext()

        return post

    }







class PersistenceService {



    static var context: NSManagedObjectContext {

        return persistentContainer.viewContext

    }



    static var persistentContainer: NSPersistentContainer = {

        let container = NSPersistentContainer(name: "AppName")



        container.loadPersistentStores(completionHandler: { (storeDescription, error) in

            if let error = error as NSError? {

                fatalError("Unresolved error (error), (error.userInfo)")

            }

        })

        return container

    }()





    static func saveContext () {

        let context = persistentContainer.viewContext

        context.perform {

            context.mergePolicy = NSMergeByPropertyObjectTrumpMergePolicy

            if context.hasChanges {

                do {

                    try context.save()

                } catch {

                    let nserror = error as NSError

                    fatalError("Unresolved error (nserror), (nserror.userInfo)")

                }

            }

        }

    }





}