具有多种结构的JSONEncoder

问题描述

我有多个JSON数据包，如下所示.

Hi I have multiple JSON Packets like I wrote below.

{
  "data" : {
    "lng" : 36.159999999999997,
    "lat" : 50.359999999999999,
    "accuracy" : 5
  },
  "header" : {
    "type" : "loc"
  }
}

还有这个

{
  "data" : {
    "time" : 15646565455,
    "tz" : "+2",
    "system" : 5
  },
  "header" : {
    "type" : "syn"
  }
}

我有用于数据包的结构，它可以用于一种数据包结构.但是如何将其用于多个数据包结构.

I have structure for my packets and it worked for one structure of packets. But how to use it for multiple packets structures.

struct Packet : Codable {
    enum StructureType : String, Codable {
        case location = "loc"
        case synchronize = "syn"
    }

    enum Status: String, Codable {
        case  OK   = "OK"
        case  NOT   = "NOT"
    }

    struct Header: Codable {
        let type: StructureType
        let status: Status?
    }
    var header: Header

    struct Data : Codable {

        struct LocationStruct : Codable {
            var lng: Double
            var lat: Double
            var accuracy: Double
        }
        struct SynchronizationStruct: Codable {
            var time: Int
            var tz: String
            var locale: String
        }
    }
    var data: Data

}

现在我要对JSON编码取决于我的数据

Now I want to encode JSON depends from my Data

let dataHeader = Packet.Header.init(type: .location, action: nil, ID: nil, dataID: nil, status: nil)
        let dataData = Packet.Data.LocationStruct.init(lng: lng, lat: lat, accuracy: acc)
        let dataObject = Packet.init(header: dataHeader, data: dataData)

        let encoder = JSONEncoder()
        encoder.outputFormatting = .prettyPrinted
        let data = try! encoder.encode(dataObject)

该怎么做，还是我需要对每个数据包使用数据结构的其他结构?

How to do that, or I need to use other structure of my data struct for each of packets?

推荐答案

我将拥有两个主要模型对象Location和Synchronization的结构.然后，我将它们定义为符合某种协议，在该协议中我们指定了如何知道哪种标头"适用于哪种类型的有效负载.然后，我将创建一个通用数据包，该数据包可以打包以下两种可能的有效负载:

I'd have structures for the two main model objects, Location and Synchronization. I'd then define them to conform to some protocol where we specified how we know which "header" goes for which type of payload. And I'd then make a generic Packet that can package these two possible payloads:

enum PayloadType: String, Codable {
    case location = "loc"
    case synchronize = "syn"
}

protocol Payload: Codable {
    var payloadType: PayloadType { get }
}

struct Location: Payload {
    let lat: Double
    let long: Double
    let accuracy: Double
    let payloadType = PayloadType.location

    enum CodingKeys: String, CodingKey {
        case lat,long,accuracy
    }
}

struct Synchronization: Payload {
    let time: Int
    let tz: String
    let system: Int
    let payloadType = PayloadType.synchronize

    enum CodingKeys: String, CodingKey {
        case time, tz, system
    }
}

struct Packet<T: Payload>: Codable {
    let data: T
    let header: PayloadType

    init(payload: T) {
        data = payload
        header = payload.payloadType
    }
}

然后您可以执行以下操作:

Then you can do:

let location = Location(lat: 36.16, long: 50.36, accuracy: 5)
let packet = Packet(payload: location)

let json = try! encoder.encode(packet)

导致:

{
  "data" : {
    "lat" : 36.159999999999997,
    "long" : 50.359999999999999,
    "accuracy" : 5
  },
  "header" : "loc"
}

或

let location = Synchronization(time: 15646565455, tz: "+2", system: 5)
let packet = Packet(payload: location)

let json = try! encoder.encode(packet)

结果:

{
  "data" : {
    "system" : 5,
    "time" : 15646565455,
    "tz" : "+2"
  },
  "header" : "syn"
}

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