SwiftUI macOS JSON convert in class Codable - json

Question

I get the following json from an api call but am having trouble making the proper structure in swift and then getting the data as an array.
JSON:
{
"status":"ok",
"users":[
{
"position":0,
"user":{
"pk":"",
"full_name":"",
"username":"",
"profile_pic_url":""
}
},...
]
}
Swift:
class Response: Codable {
var status: String
var users: [User]?
}
class User: Identifiable, Codable {
var uuid = UUID()
var pk: String
var full_name: String
var username: String
var profile_pic_url: String
enum CodingKeys: String, CodingKey {
case
pk = "user.pk",
full_name = "user.full_name",
username = "user.username",
profile_pic_url = "user.profile_pic_url"
}
}
class Fetch: ObservableObject {
#Published var results = [User]()
#Published var resultState = false
#Published var errorState = false
init(url: String) {
self.results = []
let url = URL(string: url)!
URLSession.shared.dataTask(with: url) { data, response, error in
do {
if let data = data {
let results = try JSONDecoder().decode(Response.self, from: data)
DispatchQueue.main.async {
self.results = results.users ?? []
self.resultState = true
}
print("Widget: Ok.")
} else {
self.results = []
self.resultState = true
print("Widget: No data.")
}
} catch {
self.errorState = true
self.resultState = true
print("Widget: Error", error)
}
}.resume()
}
}
Code:
#ObservedObject var fetch = Fetch(url: "")
List(fetch.results) { user in
UserItem(user: user)
}
The problem is that inside array users, it contains an object, this object contains two elements a position attribute and then the user object.
What I think I'm doing wrong is taking the user object.
Can anyone help me out?
Edit:
struct Response: Codable {
let status: String
let users: [UserType]?
}
struct UserType: Codable {
let position: Int
let user: User
}
struct User: Codable {
let pk: String
let full_name: String
let username: String
let profile_pic_url: String
enum CodingKeys: String, CodingKey {
case pk, full_name, username, profile_pic_url
}
}
class Fetch: ObservableObject {
#Published var results = [User]()
#Published var resultState = false
#Published var errorState = false
init(url: String) {
self.results = []
let url = URL(string: url)!
URLSession.shared.dataTask(with: url) { data, response, error in
do {
if let data = data {
let results = try JSONDecoder().decode(Response.self, from: data)
let users = results.users?.map { $0.user }
DispatchQueue.main.async {
self.results = users ?? []
self.resultState = true
}
print("Widget: Ok.")
} else {
self.results = []
self.resultState = true
print("Widget: No data.")
}
} catch {
self.errorState = true
self.resultState = true
print("Widget: Error", error)
}
}.resume()
}
}
List(fetch.results) { user in
UserItem(user: user)
}

Answer 1

You can try this.
struct Response: Codable {
let status: String
let users: [UserWPosition]
var userNoPositions: [UserInfo] { // computed value with only array of userinfo
users.compactMap { $0.user }
}
}
// MARK: - User with position object
struct UserWPosition: Codable {
let position: Int // commenting this will also do no effect
let user: UserInfo
}
// MARK: - UserInfo
struct UserInfo: Codable {
let pk, fullName, username, profilePicURL: String
enum CodingKeys: String, CodingKey {
case pk
case fullName = "full_name"
case username
case profilePicURL = "profile_pic_url"
}
}
Read the comments I added to the code decoding will not code a key that's not added to the struct so commenting out position will have no issue also, the hierarchy of it should be like this now I added a userNoPositions computed value in response to give array of users easily .
Simply to access the array without positions
var resp = try! JSONDecoder().decode(Response.self, from: encoded) // encoded is the data from json
print(resp.userNoPositions) // the array

Answer 2

You need an extra struct that holds the User type
struct UserType: Codable {
let position: Int
let user: User
}
Meaning the top type becomes
struct Response: Codable {
let status: String
let users: [UserType]?
}
You also need to change the CodingKeys enum since it should just contain the property names which mean the enum can be written as
enum CodingKeys: String, CodingKey {
case pk, full_name, username, profile_pic_url
}
For completeness here is the full User type
struct User: Identifiable, Codable {
var uuid = UUID()
var pk: String
var full_name: String
var username: String
var profile_pic_url: String
enum CodingKeys: String, CodingKey {
case pk, full_name, username, profile_pic_url
}
}
and when decoding then you can extract the users array with the map function
do {
let results = try JSONDecoder().decode(Response.self, from: data)
let users = results.users?.map { $0.user }
....
Note that I changed from class to struct because struct is better suited for this but class works as well. I also wonder why the users property is optional, I didn't change that but can the array really be nil?