CoreData object to JSON in Swift 3

Question

I\'m struggling to get my CoreData objects into JSON so that I can use it to send to a web server.

This is how I currently fetch my objects from CoreData:

Answer 1

In Swift 4 you can take advantage of the Encodable protocol and add the functionality directly to your Core Data object.

Assuming your NSManagedObject subclass extension looks like

extension Record {

    @NSManaged public var date: Date
    @NSManaged public var name: String
    @NSManaged public var quantity: Int32
    @NSManaged public var synched: Bool
    @NSManaged public var uuid: String

   ...

Adopt Encodable

extension Record : Encodable {

and add

private enum CodingKeys: String, CodingKey { case date, name, quantity, synched, uuid }

public func encode(to encoder: Encoder) throws {
    var container = encoder.container(keyedBy: CodingKeys.self)
    try container.encode(date, forKey: .date)
    try container.encode(name, forKey: .name)
    try container.encode(quantity, forKey: .quantity)
    try container.encode(synched, forKey: .synched)
    try container.encode(uuid, forKey: .uuid)
}

Then you can easily encode the records to JSON

do {
    records = try context.fetch(Record.fetchRequest())
    let jsonData = try JSONEncoder().encode(records)
} catch {
    print("Error fetching data from CoreData")
}