Serialize NSObject (or array of) to XML in Swift.

Serialize.swift

import Foundation

class MyClass: NSObject, NSCoding {

    var name: String
    var age: Int

    init(name: String, age: Int) {
        self.name = name
        self.age = age
    }

    // MARK: NSCoding

    func encode(with aCoder: NSCoder) {
        aCoder.encode(name, forKey: "name")
        aCoder.encode(age, forKey: "age")
    }

    required convenience init?(coder aDecoder: NSCoder) {

        guard let name = aDecoder.decodeObject(forKey: "name") as? String
            else { return nil }

        let age = aDecoder.decodeInteger(forKey: "age")
        self.init(name: name, age: age)
    }
}

/* With an object */

let o = MyClass(name: "me", age: 42)
let coderO = NSKeyedArchiver()
coderO.outputFormat = .xml
coderO.encode(o)

let decoderO = NSKeyedUnarchiver(forReadingWith: coderO.encodedData)
print(String(data: coderO.encodedData, encoding: .utf8)!)
if let decoded = decoderO.decodeObject() as? MyClass {
    print(decoded.name)
}

/* With an array */

let a = [ MyClass(name: "me", age: 42), MyClass(name: "you", age: 21) ]
let coderA = NSKeyedArchiver()
coderA.outputFormat = .xml
coderA.encode(a)

let decoderA = NSKeyedUnarchiver(forReadingWith: coderA.encodedData)
print(String(data: coderA.encodedData, encoding: .utf8)!)
if let decoded = decoderA.decodeObject() as? [MyClass] {
    decoded.forEach { print($0.name) }
}