How to parse core data's data to struct

Question

i use core data in my app. I want to parse core data's data to struct but i can't do this. I can get datas from core data. However don't know how can i parse those datas to my struct.

I know codeble json parse, if can we use that way parse to core data it will be great.

struct strUser: Codable {
    let city, country, createdDate, url, userType, validDate, fullName, bio, languages, mail, name, organization, password, photo, profession, role, surname, title: String
    let isActive: Bool
    enum CodingKeys: String, CodingKey {
        case city = "city"
        case country = "country"
        case createdDate = "created_date"
        case url = "url"
        case userType = "user_type"
        case validDate = "valid_date"
        case fullName = "full_name"
        case bio = "bio"
        case languages = "languages"
        case mail = "mail"
        case name = "name"
        case organization = "organization"
        case password = "password"
        case photo = "photo"
        case profession = "profession"
        case role = "role"
        case surname = "surname"
        case title = "title"
        case isActive
    }
}

@objc func getUser(){
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        let context = appDelegate.persistentContainer.viewContext

        let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "User")
        fetchRequest.returnsObjectsAsFaults = false

        do {

            let results = try context.fetch(fetchRequest)
            print(results)

        } catch {
            print("error")
        }
    }

I use that func for call my user from core data and i give my users like this ;

data: {
    bio = "I am a echonomist";
    city = Newyork;
    country = USA;
    "created_date" = "01-07-2019";
    "full_name" = "Barney Stinson";
    "is_active" = 1;
    languages = English;
    mail = "[email protected]";
    name = Barney;
    organization = GNB;
    password = 1234;
    photo = image;
    profession = Echonomist;
    role = Cordinator;
    surname = Stinson;
    title = title;
    url = "www.stinson.com";
    "user_type" = normal;
    "valid_date" = "01-07-2019";
}), <User: 0x600003957070> (entity: User; id: 0x9f8fcaa8f7a43527 <x-coredata://2AF3AC56-9A78-4F48-89AB-655B4129234E/User/p2> ; data: {
    bio = "I am a architect";
    city = Paris;
    country = France;
    "created_date" = "02-07-2019";
    "full_name" = "Ted Evelyn Mosby";
    "is_active" = 1;
    languages = English;
    mail = "[email protected]";
    name = "Ted Evelyn";
    organization = "Mosby Architectonics";
    password = 2345;
    photo = image2;
    profession = Architect;
    role = Architect;
    surname = Mosby;
    title = title;
    url = "www.mosby.com";
    "user_type" = normal;
    "valid_date" = "02-07-2019";
}), <User: 0x6000039570c0> (entity: User; id: 0x9f8fcaa8f7a03527 <x-coredata://2AF3AC56-9A78-4F48-89AB-655B4129234E/User/p3> ; data: {
    bio = "I am a lawyer";
    city = Roma;
    country = Italy;
    "created_date" = "03-07-2019";
    "full_name" = "Marshall Eriksen";
    "is_active" = 1;
    languages = English;
    mail = "[email protected]";
    name = Marshall;
    organization = "World Health Organization";
    password = 3456;
    photo = image3;
    profession = Lawyer;
    role = Lawyer;
    surname = Eriksen;
    title = title;
    url = "www.erisen.com";
    "user_type" = normal;
    "valid_date" = "03-27-2019";
})))]

Those are print(results) reason.

Answer 1

I would suggest writing an initializer for your User Struct (the JSON version) that takes the NSManagedObject (Core Data) User as its argument. ie:

extension StructUser {
   init(record: User) {
     // initialize all properties, ie:
     self.city = record.city
     // etc.
   } 
}

Then, you can map the objects into the Codable User struct types

let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "User")
let managedObjectUsers = try! context.fetch(fetchRequest) as! [User]
let codableUsers = managedObjectUsers.map { StructUser.init(record: $0) }