Making User FromJson compliant

User+FromJson.swift

extension User: FromJson {
  static func from(value: JsonValue) -> User? {
    return value.ifObject { json in
      User(
        id:             try json .! "id",
        name:           try json .! "name",
        email:          json .? "email",
        country:        json .? "country",
        subscription:   try json .! "subscription",
        favouriteSongs: (json ..? "favouriteSongs") ?? []
      )
    }
  }
}

// That's all you need for String/Int RawRepresentable Enums!
extension Subscription: FromJson {}

// Or you get to say how it's done!
// In this case, the country in JSON is short-coded and
// thus needs to be translated to the right Country case.
extension Country: FromJson {
  static func from(value: JsonValue) -> Country? {
    return value.ifString { str in
      switch str {
      case "nl": return .netherlands
      case "pt": return .portugal
      default:   return nil
      }
    }
  }
}

extension Song: FromJson {
  static func from(value: JsonValue) -> Song? {
    return value.ifObject { json in
      Song(
        name: try json .! "name",
        band: try json .! "band"
      )
    }
  }
}