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[英]add json array with object to Codable model in swift
[英]How to architecture a json object model in swift with Codable protocol
我正在編寫 REST Web 應用程序客戶端,並使用如下所示的 JSON:
JSON1
{
"device" : "iPhone"
"manufacturer" : "Apple"
"id" : 42
"owner" : "Steve"
}
但是 API 也可以給我這種 JSON
JSON2
{
"device" : "iPhone"
"manufacturer" : "Apple"
"id" : 42
"latitude" : 3.1415926535
"longitude" : 2.7182818284
}
所以現在在我的應用程序中,我創建了一個符合 Codable 協議的結構
struct MyStruct : Codable {
var name: String
var manufacturer: String
var owner: String?
// I prefer to use a property of type Location rather than 2 variables
var location: Location? {
guard let latitude = latitude, let longitude = longitude else {
return nil
}
return Location(latitude: latitude, longitude: longitude)
}
// Used to conform to the Codable protocol
private var latitude: Double?
private var longitude: Double?
}
struct Location {
var latitude: Double = 0.0
var longitude: Double = 0.0
}
這種架構有效,但在我看來它不是最好的或優雅的。 你知道是否存在更好的方法嗎? 我是否應該使用 2 個不同的 json 模型,例如:
struct MyStruct1 : Codable {
var name: String
var manufacturer: String
var owner: String
}
struct MyStruct2 : Codable {
var name: String
var manufacturer: String
private var latitude: Double
private var longitude: Double
}
我是 REST API 客戶端的新手,這種 JSON 似乎沒有使用好的架構。
將owner
、 latitude
和longitude
屬性設為可選。 並且僅當屬性存在時才使用decodeIfPresent
進行解碼。
您可以創建一個struct
-
struct UserData: Codable {//Confroms to Codable protocol
var id: Int
var device: String
var manufacturer: String
var owner: String? = nil//Making property optional
var latitude: Double? = nil//Making property optional
var longitude: Double? = nil//Making property optional
init(from decoder: Decoder) throws {
let values = try decoder.container(keyedBy: CodingKeys.self)
id = try values.decode(Int.self, forKey: .id)
device = try values.decode(String.self, forKey: .device)
manufacturer = try values.decode(String.self, forKey: .manufacturer)
owner = try values.decodeIfPresent(String.self, forKey: .owner)
latitude = try values.decodeIfPresent(Double.self, forKey: .latitude)
longitude = try values.decodeIfPresent(Double.self, forKey: .longitude)
}
}
示例 Json:
let jsonExample = """
{
"device" : "iPhone",
"manufacturer" : "Apple",
"id" : 42,
"owner" : "Steve"
}
""".data(using: .utf8)!
let jsonExample2 = """
{
"device" : "iPhone",
"manufacturer" : "Apple",
"id" : 42,
"latitude" : 3.1415926535,
"longitude" : 2.7182818284
}
""".data(using: .utf8)!.
用法:
//Decode struct using JSONDecoder
let jsonDecoder = JSONDecoder()
do {
let modelResult = try jsonDecoder.decode(UserData.self,from: jsonExample2)
print("owner is \(String(describing: modelResult.owner)) - latitude is \(String(describing: modelResult.latitude)) - longitude is \(String(describing: (modelResult.longitude)))")
} catch {
print(error)
}
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