iOS 错误“JSON 写入中的类型无效 (FIRTimestamp)”

Question

我正在尝试将我的数据映射到模型。我在其中使用 Firestore 快照侦听器来获取数据。在这里，我正在获取数据并映射到“用户”模型；

            do{
                let user = try User(dictionary: tempUserDic)
                print("\(user.firstName)")
            }
            catch{
                print("error occurred")
            }

这是我的模型：

struct User {
    let firstName: String
//    var lon: Double = 0.0
//    var refresh:Int = 0
//    var createdOn: Timestamp = Timestamp()
}

//Testing Codable
extension User: Codable {
    init(dictionary: [String: Any]) throws {
        self = try JSONDecoder().decode(User.self, from: JSONSerialization.data(withJSONObject: dictionary))
    }
    private enum CodingKeys: String, CodingKey {
        case firstName = "firstName"
    }
}

如果我错了请纠正我。

崩溃是因为我在数据中获取“时间戳”。

从监听器获取的数据：

用户词典：

[\"firstName\": Ruchira,
 \"lastInteraction\": FIRTimestamp: seconds=1576566738 nanoseconds=846000000>]"

如何将“时间戳”映射到模型？

尝试过“CodableFirstore” https://github.com/alickbass/CodableFirebase

Answer 1

我通过将FIRTimestamp字段转换为Double（秒）解决了这个问题，以便JSONSerialization可以相应地解析它。

 let items: [T] = documents.compactMap { query in
   var data = query.data() // get a copy of the data to be modified.

   // If any of the fields value is a `FIRTimestamp` we replace it for a `Double`.
   if let index = (data.keys.firstIndex{ data[$0] is FIRTimestamp }) {

     // Convert the field to `Timestamp`
     let timestamp: Timestamp = data[data.keys[index]] as! Timestamp

     // Get the seconds of it and replace it on the `copy` of `data`.
     data[data.keys[index]] = timestamp.seconds

    }

    // This should not complain anymore.
    guard let data = try? JSONSerialization.data(
       withJSONObject: data, 
       options: .prettyPrinted
    ) else { return nil }

    // Make sure your decoder setups the decoding strategy to `. secondsSince1970` (see timestamp.seconds documentation).
    let decoder = JSONDecoder()
    decoder.dateDecodingStrategy = .secondsSince1970
    return try? decoder.decode(T.self, from: data)
 }

// Use now your beautiful `items`
return .success(items)