How convert data to Json in Realm version 10.15.0 - json

Question

in the realm version 10.7.1 it used this code but when migrating to 10.15.0 it is no longer possible because the ListBase class no longer exists
extension Object {
func toWebServiceRequest() -> [String:AnyObject] {
let properties = self.objectSchema.properties.map { $0.name }
var dicProps = [String:AnyObject]()
for (key, value) in self.dictionaryWithValues(forKeys: properties) {
if let value = value as? ListBase {
dicProps[key] = value.toArray() as AnyObject
} else if let value = value as? Object {
dicProps[key] = value.toWebServiceRequest() as AnyObject
} else {
dicProps[key] = value as AnyObject
}
}
return dicProps
}
}
extension ListBase {
func toArray() -> [AnyObject] {
var _toArray = [AnyObject]()
for i in 0..<self._rlmArray.count {
let obj = unsafeBitCast(self._rlmArray[i], to: Object.self)
_toArray.append(obj.toWebServiceRequest() as AnyObject)
}
return _toArray
}
}

Answer 1

The mongo team wants you to use the Codable protocol rather than some custom encoding mechanism. This is really the proper way to do it, otherwise you have to rely on Realm implementation details.
class Parent: Object, Codable {
#Persisted var name: String = ""
#Persisted var children: List<Child>
convenience init(name: String, children: [Child] = []) {
self.init()
self.name = name
self.children.append(objectsIn: children)
}
}
If the server is expecting keys different from your object's property names you can define custom CodingKeys:
class Child: Object, Codable {
#Persisted var id: Int = 0
#Persisted var name: String = ""
enum CodingKeys: String, CodingKey {
case id = "_id"
case name = "name"
}
convenience init(id: Int, name: String) {
self.init()
self.id = id
self.name = name
}
}
Usage is simple:
func makeParent() -> Parent {
Parent(name: "Alex", children: [
Child(id: 1, name: "Jim"),
Child(id: 2, name: "Tom"),
Child(id: 3, name: "Sam"),
Child(id: 4, name: "Joe"),
])
}
func encode<Item: Encodable>(_ item: Item) throws -> Data {
let encoder = JSONEncoder()
return try encoder.encode(item)
}
func convertDataToString(_ data: Data) throws -> String? {
return String(data: data, encoding: .utf8)
}
func decode<Item: Decodable>(_ type: Item.Type, from data: Data) throws -> Item {
let decoder = JSONDecoder()
return try decoder.decode(type, from: data)
}
func executeProgram() throws {
let parent = makeParent()
let encodedJSONData = try encode(parent)
guard let encodedJSONString = try convertDataToString(encodedJSONData) else {
throw Error.badJSON
}
print("JSON: \(encodedJSONString)")
let decodedParent = try decode(Parent.self, from: encodedJSONData)
print("Decoded Parent: \(decodedParent)")
}
On the encode route this results in:
JSON:
{"name":"Alex","children":[{"_id":1,"name":"Jim"},{"_id":2,"name":"Tom"},{"_id":3,"name":"Sam"},{"_id":4,"name":"Joe"}]}
And on the decode route this results in:
Decoded Parent: Parent { name = Alex; children = List
<0x600000a2b800> ( [0] Child { id = 1; name = Jim; }, [1]
Child { id = 2; name = Tom; }, [2] Child { id = 3;
name = Sam; }, [3] Child { id = 4; name = Joe; } ); }
You can obviously omit the String conversion just work with the resulting Data.