How to implement Codable in a custom subclass (Swift 4) [duplicate] - swift

Should the use of class inheritance break the Decodability of class. For example, the following code
class Server : Codable {
var id : Int?
}
class Development : Server {
var name : String?
var userId : Int?
}
var json = "{\"id\" : 1,\"name\" : \"Large Building Development\"}"
let jsonDecoder = JSONDecoder()
let item = try jsonDecoder.decode(Development.self, from:json.data(using: .utf8)!) as Development
print(item.id ?? "id is nil")
print(item.name ?? "name is nil") here
output is:
1
name is nil
Now if I reverse this, name decodes but id does not.
class Server {
var id : Int?
}
class Development : Server, Codable {
var name : String?
var userId : Int?
}
var json = "{\"id\" : 1,\"name\" : \"Large Building Development\"}"
let jsonDecoder = JSONDecoder()
let item = try jsonDecoder.decode(Development.self, from:json.data(using: .utf8)!) as Development
print(item.id ?? "id is nil")
print(item.name ?? "name is nil")
output is:
id is nil
Large Building Development
And you can't express Codable in both classes.

I believe in the case of inheritance you must implement Coding yourself. That is, you must specify CodingKeys and implement init(from:) and encode(to:) in both superclass and subclass. Per the WWDC video (around 49:28, pictured below), you must call super with the super encoder/decoder.
required init(from decoder: Decoder) throws {
// Get our container for this subclass' coding keys
let container = try decoder.container(keyedBy: CodingKeys.self)
myVar = try container.decode(MyType.self, forKey: .myVar)
// otherVar = ...
// Get superDecoder for superclass and call super.init(from:) with it
let superDecoder = try container.superDecoder()
try super.init(from: superDecoder)
}
The video seems to stop short of showing the encoding side (but it's container.superEncoder() for the encode(to:) side) but it works in much the same way in your encode(to:) implementation. I can confirm this works in this simple case (see playground code below).
I'm still struggling with some odd behavior myself with a much more complex model I'm converting from NSCoding, which has lots of newly-nested types (including struct and enum) that's exhibiting this unexpected nil behavior and "shouldn't be". Just be aware there may be edge cases that involve nested types.
Edit: Nested types seem to work fine in my test playground; I now suspect something wrong with self-referencing classes (think children of tree nodes) with a collection of itself that also contains instances of that class' various subclasses. A test of a simple self-referencing class decodes fine (that is, no subclasses) so I'm now focusing my efforts on why the subclasses case fails.
Update June 25 '17: I ended up filing a bug with Apple about this. rdar://32911973 - Unfortunately an encode/decode cycle of an array of Superclass that contains Subclass: Superclass elements will result in all elements in the array being decoded as Superclass (the subclass' init(from:) is never called, resulting in data loss or worse).
//: Fully-Implemented Inheritance
class FullSuper: Codable {
var id: UUID?
init() {}
private enum CodingKeys: String, CodingKey { case id }
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
id = try container.decode(UUID.self, forKey: .id)
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(id, forKey: .id)
}
}
class FullSub: FullSuper {
var string: String?
private enum CodingKeys: String, CodingKey { case string }
override init() { super.init() }
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
let superdecoder = try container.superDecoder()
try super.init(from: superdecoder)
string = try container.decode(String.self, forKey: .string)
}
override func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(string, forKey: .string)
let superencoder = container.superEncoder()
try super.encode(to: superencoder)
}
}
let fullSub = FullSub()
fullSub.id = UUID()
fullSub.string = "FullSub"
let fullEncoder = PropertyListEncoder()
let fullData = try fullEncoder.encode(fullSub)
let fullDecoder = PropertyListDecoder()
let fullSubDecoded: FullSub = try fullDecoder.decode(FullSub.self, from: fullData)
Both the super- and subclass properties are restored in fullSubDecoded.

Found This Link - Go down to inheritance section
override func encode(to encoder: Encoder) throws {
try super.encode(to: encoder)
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(employeeID, forKey: .employeeID)
}
For Decoding I did this:
required init(from decoder: Decoder) throws {
try super.init(from: decoder)
let values = try decoder.container(keyedBy: CodingKeys.self)
total = try values.decode(Int.self, forKey: .total)
}
private enum CodingKeys: String, CodingKey
{
case total
}

🚀 Swift introduced Property Wrappers in 5.1 I implemented a library called SerializedSwift that uses the power of property wrappers to Decode and Encode JSON data to objects.
One of my main goals was, to make inherited object to decode out of the box, without additonal init(from decoder: Decoder) overrides.
import SerializedSwift
class User: Serializable {
#Serialized
var name: String
#Serialized("globalId")
var id: String?
#Serialized(alternateKey: "mobileNumber")
var phoneNumber: String?
#Serialized(default: 0)
var score: Int
required init() {}
}
// Inherited object
class PowerUser: User {
#Serialized
var powerName: String?
#Serialized(default: 0)
var credit: Int
}
It also supports custom coding keys, alternate keys, default values, custom transformation classes and many more features to be included in the future.
Available on GitHub (SerializedSwift).

I was able to make it work by making my base class and subclasses conform to Decodable instead of Codable. If I used Codable it would crash in odd ways, such as getting a EXC_BAD_ACCESS when accessing a field of the subclass, yet the debugger could display all the subclass values with no problem.
Additionally, passing the superDecoder to the base class in super.init() didn't work. I just passed the decoder from the subclass to the base class.

How about using the following way?
protocol Parent: Codable {
var inheritedProp: Int? {get set}
}
struct Child: Parent {
var inheritedProp: Int?
var title: String?
enum CodingKeys: String, CodingKey {
case inheritedProp = "inherited_prop"
case title = "short_title"
}
}
Additional info on composition: http://mikebuss.com/2016/01/10/interfaces-vs-inheritance/

Here is a library TypePreservingCodingAdapter to do just that (can be installed with Cocoapods or SwiftPackageManager).
The code below compiles and works just fine with Swift 4.2. Unfortunately for every subclass you'll need to implement encoding and decoding of properties on your own.
import TypePreservingCodingAdapter
import Foundation
// redeclared your types with initializers
class Server: Codable {
var id: Int?
init(id: Int?) {
self.id = id
}
}
class Development: Server {
var name: String?
var userId: Int?
private enum CodingKeys: String, CodingKey {
case name
case userId
}
init(id: Int?, name: String?, userId: Int?) {
self.name = name
self.userId = userId
super.init(id: id)
}
required init(from decoder: Decoder) throws {
try super.init(from: decoder)
let container = try decoder.container(keyedBy: CodingKeys.self)
name = try container.decodeIfPresent(String.self, forKey: .name)
userId = try container.decodeIfPresent(Int.self, forKey: .userId)
}
override func encode(to encoder: Encoder) throws {
try super.encode(to: encoder)
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(userId, forKey: .userId)
}
}
// create and adapter
let adapter = TypePreservingCodingAdapter()
let encoder = JSONEncoder()
let decoder = JSONDecoder()
// inject it into encoder and decoder
encoder.userInfo[.typePreservingAdapter] = adapter
decoder.userInfo[.typePreservingAdapter] = adapter
// register your types with adapter
adapter.register(type: Server.self).register(type: Development.self)
let server = Server(id: 1)
let development = Development(id: 2, name: "dev", userId: 42)
let servers: [Server] = [server, development]
// wrap specific object with Wrap helper object
let data = try! encoder.encode(servers.map { Wrap(wrapped: $0) })
// decode object back and unwrap them force casting to a common ancestor type
let decodedServers = try! decoder.decode([Wrap].self, from: data).map { $0.wrapped as! Server }
// check that decoded object are of correct types
print(decodedServers.first is Server) // prints true
print(decodedServers.last is Development) // prints true

Swift 5
The compiler synthesises decodable code only for a type that directly adopts Codable protocol so that you observe decoding for a single of your type in inheritance.
But you can try next generic approach with KeyValueCoding package (https://github.com/ikhvorost/KeyValueCoding) and this package provides access to all properties metadata and allows to get/set any property for pure swift types dynamically. The idea is to make a base Coding class which adopts KeyValueCoding and implements decoding of all available properties in init(from: Decoder):
class Coding: KeyValueCoding, Decodable {
typealias DecodeFunc = (KeyedDecodingContainer<_CodingKey>, _CodingKey) throws -> Any?
struct _CodingKey: CodingKey {
let stringValue: String
let intValue: Int?
init(stringValue: String) {
self.stringValue = stringValue
self.intValue = Int(stringValue)
}
init(intValue: Int) {
self.stringValue = "\(intValue)"
self.intValue = intValue
}
}
static func decodeType<T: Decodable>(_: T.Type) -> (type: T.Type, f: DecodeFunc) {
(T.self, { try $0.decode(T.self, forKey: $1) })
}
static var decodeTypes: [(Any.Type, DecodeFunc)] = [
decodeType(Int.self),
decodeType(Int?.self),
decodeType(String.self),
decodeType(String?.self),
// Other types to support...
]
required init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: _CodingKey.self)
try container.allKeys.forEach { codingKey in
let key = codingKey.stringValue
guard let property = (properties.first { $0.name == key }),
let item = (Self.decodeTypes.first { property.type == $0.0 })
else {
return
}
var this = self
this[key] = try item.1(container, codingKey)
}
}
}
It is important to provide all supported types to decode in decodeTypes variable.
How to use:
class Server: Coding {
var id: Int?
}
class Development : Server {
var name: String = ""
}
class User: Development {
var userId: Int = 0
}
func decode() {
let json = "{\"id\": 1, \"name\": \"Large Building Development\", \"userId\": 123}"
do {
let user = try JSONDecoder().decode(User.self, from:json.data(using: .utf8)!)
print(user.id, user.name, user.userId) // Optional(1) Large Building Development 123
}
catch {
print(error.localizedDescription)
}
}

Related

Swift Decodable: Inject value in nested generic property

I have this API response structure (from Strapi v4):
{
"data": [
{
"id": 1,
"attributes": {
"description": "test",
}
}
]
}
I have this generic code to handle API responses and to inject the ID to my child object:
struct StrapiArrayResponse<Content: StrapiDataObjectContent>: Codable {
var data: [StrapiDataObject<Content>]
}
struct StrapiDataObject<Content: StrapiDataObjectContent>: Codable {
let id: Int
var attributes: Content
init(from decoder: Decoder) throws {
let container: KeyedDecodingContainer<CodingKeys> = try decoder.container(keyedBy: CodingKeys.self)
self.id = try container.decode(Int.self, forKey: .id)
self.attributes = try container.decode(Content.self, forKey: .attributes)
self.attributes.id = id
}
}
protocol StrapiDataObjectContent: Codable {
var id: Int! { get set } // I don't want this to be an Optional
}
I want my id to be a let instead of an optional var.
Is there a better way to inject the ID to my child objects (StrapiDataObjectContent)?
Here is a solution for the problem but it isn't so straightforward and requires some work.
Since you want id to be a constant we need a way to initialise Content with it so one way then is to add an init to the protocol.
protocol StrapiDataObjectContent: Codable {
var id: Int { get } //also removed 'set'
init(id: Int, copy: Self)
}
As you see this init takes an already existing object as parameter so this is kind of a copy method
So an implementation (based on the json in the question) could then be
init(id: Int, copy: Test) {
self.id = id
self.description = copy.description
}
We then need to change init(from:) in StrapiDataObject to
init(from decoder: Decoder) throws {
let container: KeyedDecodingContainer<CodingKeys> = try decoder.container(keyedBy: CodingKeys.self)
self.id = try container.decode(Int.self, forKey: .id)
let attributes = try container.decode(Content.self, forKey: .attributes)
self.attributes = Content(id: id, copy: attributes)
}
Now this compiles but we will get a runtime error since id is expected by the decoder for Content but doesn't exists in the json.
So this leads to the major drawback of this solution, every type conforming to StrapiDataObjectContent needs to implement a custom init(from:) just to avoid decoding the id property
To demonstrate here is a full example (based on the json in the question)
struct Test: StrapiDataObjectContent {
let id: Int
let description: String
init(from decoder: Decoder) throws {
id = 0
let container = try decoder.container(keyedBy: CodingKeys.self)
description = try container.decode(String.self, forKey: .description)
}
init(id: Int, copy: Test) {
self.id = id
self.description = copy.description
}
}

Swift struct with custom encoder and decoder cannot conform to 'Encodable'

[Edited to provide a minimal reproducible example ]
This is the complete struct without non relevant vars and functions
InstrumentSet.swift
import Foundation
struct InstrumentsSet: Identifiable, Codable {
private enum CodingKeys: String, CodingKey {
case name = "setName"
case tracks = "instrumentsConfig"
}
var id: String { name }
var name: String
var tracks: [Track]
}
Track.swift
import Foundation
extension InstrumentsSet {
struct Track: Identifiable, Encodable {
private enum TrackKeys: String, CodingKey {
case id = "trackId"
case effects
}
let id: String
var effects: [Effect]?
}
}
extension InstrumentsSet.Track: Decodable {
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: TrackKeys.self)
id = try container.decode(String.self, forKey: .id)
effects = try container.decodeIfPresent([Effect].self, forKey: .effects)
}
}
Effect.swift
import Foundation
import AudioKit
import SoundpipeAudioKit
extension InstrumentsSet.Track {
enum Effect: Decodable {
private enum EffectKeys: String, CodingKey {
case effectType = "effectName"
case cutoffFrequency
case resonance
}
case lowPassFilter(LowPassFilterEffect)
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: EffectKeys.self)
let effectType = try container.decode(Effect.EffectType.self, forKey: .effectType)
switch effectType {
case .lowPassFilter:
let cutOffFrequency = try container.decode(ValueAndRange.self, forKey: .cutoffFrequency)
let resonance = try container.decode(ValueAndRange.self, forKey: .resonance)
self = .lowPassFilter(LowPassFilterEffect(cutOffFrequency: cutOffFrequency, resonance: resonance))
default:
fatalError("Not implemented!")
}
}
}
}
extension InstrumentsSet.Track.Effect {
enum EffectType: String, Decodable {
case lowPassFilter
}
}
extension InstrumentsSet.Track.Effect: Encodable {
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: EffectKeys.self)
//FIXME: This is the location of the error: Type 'ValueAndRange.Type' cannot conform to 'Encodable'
try container.encode(ValueAndRange.self, forKey: .cutoffFrequency)
}
}
The problem is ValueAndRange.self not not conforming to Encodable
I've followed multiple examples to get to this implementation:
import Foundation
import AudioKit
struct ValueAndRange: Encodable {
private enum ValueRangeKeys: String, CodingKey {
case value
case range
}
static var zero: ValueAndRange { .init(value: 0, range: [0, 0]) }
var value: AUValue
var range: [Double]
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: ValueRangeKeys.self)
try container.encode(value, forKey: .value)
try container.encode(range, forKey: .range)
}
}
extension ValueAndRange: Decodable {
init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: ValueRangeKeys.self)
value = try container.decode(AUValue.self, forKey: .value)
range = try container.decode([Double].self, forKey: .range)
}
}
I cannot see why this struct should not conform to Encodable. Maybe any of you got betters eyes (and brains) then I got?
Your encode function is incorrectly trying to encode a type, ValueAndRange.self, rather than a value.
Looking at the init(from:) method I think your encode function should look something like this
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: EffectKeys.self)
switch self {
case .lowPassFilter(let effect):
try container.encode(effect.cutOffFrequency, forKey: .cutoffFrequency)
try container.encode(effect.resonance, forKey: .resonance)
}
}
I didn't include .effectType in this code since I am uncertain of its usage (isn't it always the same hard coded string?).

Using Decodable with injected properties

Is there any way to use Decodable with injected property?
final class Score: Decodable {
let value: Int?
let uniqueId: String
convenience init(from decoder: Decoder/*, uniqueId: String*/) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
try container.decodeIfPresent(Int.self, forKey: .value).flatMap { value = $0 }
// self.uniqueId = uniqueId
[... other properties parsing ...]
}
}
Example call:
final class Exam {
let identifier: Int
let scores: [Score]
convenience init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
identifier = try container.decode(Int.self, forKey: .identifier)
scores = try container.decode([Score].self, forKey: .scores)
// I need to pass Exam's identifier to `score` on init, because it will generate Score's `uniqueId `
[... other properties parsing ...]
}
}
That would end with error with missing uniqueId, which I need to have after init but it's not in the JSON. Since it's identifier, making it optional and setting outside is not a proper way to handle it.
I'd love to inject it the way it's commented above, but how to do it?
There is no way to extend the initialiser because it's being called indirectly and there is no API provided to extend it. Thus, there are several ways to bypass it:
BEST: Inject the value into Decoder's userInfo if possible.
Create separate class for Response and separate for model. Example below.
Use plain JSONSerialization instead of Decodable.
As #JoakimDanielson suggested, create random identifier inside default initialiser. The issue is that it's not reproducable, so in case you're saving it to the DB, you'll always override the data, since the ID with each parsing would be different.
Example for approach 2:
final class ScoreResponse: Decodable {
let value: Int?
convenience init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
try container.decodeIfPresent(Int.self, forKey: .value).flatMap { value = $0 }
[... other properties parsing ...]
}
}
final class Score {
let value: Int?
let uniqueId: String
convenience init(from response: ScoreResponse, uniqueId: String) {
self.value = response.value // etc with other properties
self.uniqueId = uniqueId
}
}
final class Exam: Decodable {
let identifier: String
let scores: [Score] = []
convenience init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
identifier = try container.decode(String.self, forKey: .identifier)
try container.decodeIfPresent([ScoreResponse].self, forKey: .scores).forEach {
scores.append({ Score(from: $0, uniqueId: identifier) })
}
}

How to encode Realm's List<> type

I am trying to encode my Realm database to JSON. Everything is working except the List<> encoding. So my question is, how would you encode List<>? Because the List doesn't conform to Encodable neighter Decodable protocol.
Right now I am doing this:
#objcMembers class User: Object, Codable{
dynamic var name: String = ""
let dogs = List<Dog>()
private enum UserCodingKeys: String, CodingKey {
case name
case dogs
}
convenience init(name: String) {
self.init()
self.name = name
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: UserCodingKeys.self)
try container.encode(name, forKey: .name)
}
#objcMembers class Dog: Object, Codable{
dynamic var name: String = ""
dynamic var user: User? = nil
private enum DogCodingKeys: String, CodingKey {
case name
}
convenience init(name: String) {
self.init()
name = name
}
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: DogCodingKeys.self)
try container.encode(name, forKey: .name)
}
}
and like this I am trying to do it:
var json: Any?
let user = RealmService.shared.getUsers()
var usersArray = [User]()
for user in users{
usersArray.append(user)
}
let jsonEncoder = JSONEncoder()
let jsonDecoder = JSONDecoder()
let encodedJson = try? jsonEncoder.encode(portfoliosArray)
if let data = encodedJson {
json = try? JSONSerialization.jsonObject(with: data, options: .allowFragments)
if let json = json {
print(String(describing: json))
}
}
So the question is how I am able to encode the List<Dog>?
To make a Realm object model class with a property of type List conform to Encodable, you can simply convert the List to an Array in the encode(to:) method, which can be encoded automatically.
extension User: Encodable {
func encode(to encoder: Encoder) throws {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(self.username, forKey: .username)
let dogsArray = Array(self.dogs)
try container.encode(dogsArray, forKey: .dogs)
}
}
Test classes I used (slightly different from the ones in your question, but I already had these on hand and the methods in question will be almost identical regardless of the variable names):
class Dog: Object,Codable {
#objc dynamic var id:Int = 0
#objc dynamic var name:String = ""
}
class User: Object, Decodable {
#objc dynamic var id:Int = 0
#objc dynamic var username:String = ""
#objc dynamic var email:String = ""
let dogs = List<Dog>()
private enum CodingKeys: String, CodingKey {
case id, username, email, dogs
}
required convenience init(from decoder: Decoder) throws {
self.init()
let container = try decoder.container(keyedBy: CodingKeys.self)
id = try container.decode(Int.self, forKey: .id)
username = try container.decode(String.self, forKey: .username)
email = try container.decode(String.self, forKey: .email)
let dogsArray = try container.decode([Dog].self, forKey: .dogs)
dogs.append(objectsIn: dogsArray)
}
}
Test the encoding/decoding:
let userJSON = """
{
"id":1,
"username":"John",
"email":"example#ex.com",
"dogs":[
{"id":2,"name":"King"},
{"id":3,"name":"Kong"}
]
}
"""
do {
let decodedUser = try JSONDecoder().decode(User.self, from: userJSON.data(using: .utf8)!)
let encodedUser = try JSONEncoder().encode(decodedUser)
print(String(data: encodedUser, encoding: .utf8)!)
} catch {
print(error)
}
Output:
{"username":"John","dogs":[{"id":2,"name":"King"},{"id":3,"name":"Kong"}]}
You could resort to a mini-hack by making List conform to Encodable:
extension List: Encodable {
public func encode(to coder: Encoder) throws {
// by default List is not encodable, throw an exception
throw NSError(domain: "SomeDomain", code: -1, userInfo: nil)
}
}
// let's ask it to nicely encode when Element is Encodable
extension List where Element: Encodable {
public func encode(to coder: Encoder) throws {
var container = coder.unkeyedContainer()
try container.encode(contentsOf: self)
}
}
Two extensions are needed as you can't add protocol conformance and where clauses at the same time.
Also note that this approach doesn't provide compile-time checks - e.g. a List<Cat> will throw an exception an runtime if Cat is not encodable, instead of a nice compile time error.
The upside is lot of boilerplate code no longer needed:
#objcMembers class User: Object, Encodable {
dynamic var name: String = ""
let dogs = List<Dog>()
convenience init(name: String) {
self.init()
self.name = name
}
}
#objcMembers class Dog: Object, Encodable {
dynamic var name: String = ""
dynamic var user: User? = nil
convenience init(name: String) {
self.init()
name = name
}
}
This is also scalable, as adding new classes don't require any encoding code, but with the mentioned downside of not being fully type safe at compile time.

`RLMArray` does not conform to protocol 'Encodable'

I want to Do:
Using JSONDecoder(), I convert json to Realm object.
And I save this object to Realm databases.
Problem:
RLMArray don't apply Codable protocol.
I could be conformed Decodable protocol, but Codable I couldn't.
Error Message:
Type 'Person' does not conform to protocol 'Encodable'
Code:
public class Hobby: Object, Codable {
#objc dynamic var title: String?
#objc dynamic var category: String?
}
public class Person: Object, Codable { // Error: Type 'Person' does not conform to protocol 'Encodable'
#objc dynamic var name: String?
#objc dynamic var hobbies: RLMArray<Hobby>?
required convenience public init(from decoder: Decoder) throws {
self.init()
let container = try decoder.container(keyedBy: CodingKeys.self)
name = try container.decode(String.self, forKey: .name)
hobbies = try container.decode(RLMArray<Hobby>?.self, forKey: .hobbies)
}
}
func sample() {
let person = try? JSONDecoder().decode(Person.self, from: "{\"name\" : \"aaa\",\"hobbies\" : [{\"title\" : \"fishing\",\"category\" : \"outdoor\"},{\"title\" : \"reading\",\"type\" : \"indoor\"}]}".data(using: .utf8)!)
print(person)
let realm = try! Realm()
try! realm.write {
realm.add(person!)
}
}
Do you have some ideas?
Swift4
RealmSwift
Codable is the exact same as Decodable + Encodable. If you want to conform to Codable you will need to implement the encoding functions, which for your Person object would be:
enum CodingKeys: String, CodingKey {
case name
case hobbies
// or: case hobbies = "customHobbiesKey" if you want to encode to a different key
}
func encode(to encoder: Encoder) throws {
do {
var container = encoder.container(keyedBy: CodingKeys.self)
try container.encode(name, forKey: .name)
try container.encode(hobbies, forKey: .hobbies)
} catch {
print(error)
}
}
Add this to your Person class, and then implement the same thing for your Hobby class.
Because i'm not sure if you even want to encode: If all you need to do is create Realm-Objects from Json I would simply replace 'Codable' with the'Decodable'-Protocol.
EDIT: I noticed the issue is about the RLMArray. I'm not sure how codable works with RLMArray, but if it doesn't work you could try replacing the declaration with
let hobbies = List<Hobby>()
and then in init() replace the 'hobbies' line with:
let tempHobbyList: [Hobby] = try container.decode([Hobby].self, forKey: .hobbies)
self.hobbies.append(objectsIn: tempHobbyList)
That's how I got my lists with realmObjects to work with codable