swift中标准嵌套JSON的可解码包装器

Question

我正在使用一个api，它遵循一个非常相似的响应结构：

{
"error": "string item",
"success": true,
"result": {
"users" : [
{
"id": "20001",
"firstname": "John",
"lastname" : "Smith",
"address": "123 king street",
"email": "[e-mail]",
"mobile": "0412345678"
},
{
"id": "20002",
"firstname": "Jack",
"lastname": "Master",
"address": "123 rainbow road",
"email": "[e-mail]",
"mobile": "0412345678"
}
]
}
}

api根据端点返回不同的结果。我想创建一个标准的可解码json响应结构。然后，我只为每个不同的结果类型创建一个新的可解码结构。

像这样的东西会很理想：

struct JSONResponse<T: Decodable>: Decodable {
var error: String
var success: Bool
var result: T
}

以下是我尝试做的

struct User: Decodable {
var id: String
var firstName: String
var lastName: String
var email: String

enum CodingKeys: String, CodingKey {
case users
}

enum UserKeys: String, CodingKey {
case id, firstName = "firstname", lastName = "lastname", email, mobile
}

init(from decoder: Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
let nestedContainer = try container.nestedContainer(keyedBy: UserKeys.self, forKey: .users)
id = try nestedContainer.decode(String.self, forKey: .id)
firstName = try nestedContainer.decode(String.self, forKey: .firstName)
lastName = try nestedContainer.decode(String.self, forKey: .lastName)
email = try nestedContainer.decode(String.self, forKey: .email)
}

}

然后以类似的方式解码许多不同的响应

let res = try! JSONDecoder().decode(JSONResponse<User>.self, from: responseData!)

Answer 1

在这种特定情况下，您有多个User对象，因此您需要某种容器：

struct Users: Decodable {
var users: [User]
}

User也不需要这么复杂：

struct User: Decodable {
var id: String
var firstName: String
var lastName: String
var email: String
}

然后解码为：

let users = JSONDecoder().decode(JSONResponse<Users>.self, from: responseData)