Im trying to make generic structs on SWIFT to work with JSON and Codable, but i dont know if it is possible.
Without generics, it works.
struct apiContainer: Decodable {
let meta: Meta
let result: [Client]
}
I have a struct named "Client" and I would like to have other structs, for example: owner, plant and so on.
All JSON response has to go to apiContainer. It has Meta and [Client].
My goal is to make [Client] being [T] so i can pass any struct to apiContainer.
Bellow is a piece of a code that im trying on the playground.
Questions:
Is it possible?
How can I make it (both on struct and the json.decode line)
import PlaygroundSupport
import UIKit
import Foundation
struct Client: Decodable {
let name: String
let postal_code: String
let city: String
}
struct Meta: Decodable {
let sucess: String
let value: String
}
struct apiContainer<T>: Decodable {
let meta: Meta
let result: [T]
}
let json = """
{
"meta": {
"sucess": "yes",
"value": "123"
},
"result": [
{
"name": "Name 1",
"postal_code": "PC1",
"city": "City 1",
"address": "01 Street"
},
{
"name": "Name 2",
"postal_code": "PC2",
"city": "City 2",
"address": "02 Street"
}
]
}
""".data(using: .utf8)!
let converted = try JSONDecoder().decode(apiContainer.self, from: json)
print(converted.result)
print(converted.meta)
struct apiContainer<T>: Decodable
Should be
struct ApiContainer<T: Decodable>: Decodable
And
try JSONDecoder().decode(apiContainer.self, from: json)
Should be
try JSONDecoder().decode(ApiContainer<Client>.self, from: json)
And voilà! It works.
Related
Faced a difficult problem for me, when receiving data I don’t know how to decompose data in one array.
The responsible variable contains different types of data.
Do I get it right? I think in the initializer to go through the possible options and substitute the desired one? What type should the variable of this array be?
[
{
"id": 42,
"created_at": "2021-09-08T08:55:58.000000Z",
"updated_at": "2021-09-08T08:55:58.000000Z",
"link": "u4986",
"type": "u",
"responsible": {
"id": 4986,
"type": "management_company",
"email": "X#X.com",
"phone": "+0000000000",
"comment": null,
"first_name": "Alex",
"second_name": "Hook"
}
},
{
"id": 43,
"created_at": "2021-09-08T08:55:58.000000Z",
"updated_at": "2021-09-08T08:55:58.000000Z",
"link": "r14",
"type": "r",
"responsible": {
"id": 14,
"name": "manager",
"guard_name": "api",
"created_at": "2021-06-15T19:20:20.000000Z",
"updated_at": "2021-06-15T19:20:20.000000Z"
}
}
]
How to make an initializer for MyJson
struct MyJson: Codable {
let id: Int
let createdAt: String
let updatedAt: String
let link: String
let type: String
let responsible: Any
}
// MARK: - Responsible
struct User: Codable {
let id: Int
let type, email, phone, comment: String
let firstName, secondName: String
}
struct UserCategory: Codable {
let id: Int
let name, guardName, createdAt, updatedAt: String
}
In swift JSON parsing is pretty straightforward, build an object that reflects your JSON (I've just built an example based on your JSON here):
struct JsonExample: Decodable {
let id: Int
let responsible: [Responsible]
struct Responsible: Decodable {
let id: Int
let email: String
let guard_name: String
}
}
and then just decode it
let jsonData = "json_string".data(using: .utf8)!
do {
let decoded = try JSONDecoder().decode([JsonExample].self, from: jsonData)
} catch let error {
print(error.localizedDescription)
}
If you want to distinguish between nested objects you can use init and use a property inside your JSON to get the job done
init(from decoder : Decoder) throws {
let container = try decoder.container(keyedBy: CodingKeys.self)
self.id = try container.decode(Int.self, forKey: .id)
let type = try container.decode(String.self, forKey: .type)
if type == "a" {
let data = try container.decode([ResponsibleA].self, forKey: . responsible)
responsible = .responsibleA(data)
} else { // add better error handling
let data = try container.decode([ResponsibleB].self, forKey: . responsible)
responsible = .responsibleB(data)
}
}
Completed the task for a very long time. Finally I solved the problem. If you are facing this problem. You will find the solution here Indeterminate Types with Codable in Swift
I want to load JSON that contains a list of dictionary, for example
{error: false, "objects": [{"id": 1, "name": "cat"}, {"id": 2, "name": "dog"}, {"id": 3, "name": "fish"}]
How could this be defined in a
struct name: Codable, Identifiable {
}
to be used in JSONDecoder to decode the received data.
How can the struct be written to define this datatype
struct data: Codable {
let error: Bool
let objects: [dataObjects]
}
struct dataObjects: Codable {
let id: Int
let name: String
}
I am making an HTTP GET request and I want to save the JSON response that looks like this:
{
"code": 200,
"status": "success",
"patients": [
{
"_id": "5e77c7bbc7cbd30024f3eadb",
"name": "Bogdan Patient",
"username": "bogdanp",
"phone": "0732958473"
},
{
"_id": "5e77c982a2736a0024e895fa",
"name": "Robert Patient",
"username": "robertp",
"phone": "0739284756"
}
]
}
And here is my struct:
struct Doctor: Codable, Identifiable {
let id = UUID()
let patients: [Patients]
}
struct Patients: Codable {
let id: String
let name: String
let phone: String
}
As per your model, id is expected in the JSON whereas the keyname in the JSON is _id.
You can use CodingKeys to fix this:
struct Patients: Codable {
let id: String
let name: String
let phone: String
enum CodingKeys: String, CodingKey {
case id = "_id"
case name
case phone
}
}
CodingKeys creates a map between the keynames in your model and the keynames in the JSON response.
There are other reasons to use CodingKeys but for your current purpose this is enough.
Read More: Codable in Swift
{"dataList":{"1547795650562": {
"c0a8007b-6759-111d-8167-59e8dabe0086": {
"recordDate": 1547795650562,
"resultValue": "160",
"vitalParameter": {
"uom": {
"code": "KG",
"name": "KG",
"id": "c0a8007b-6759-111d-8167-59e76204007f"
},
"resultType": {
"code": "VSRTNUMERIC",
"name": "Numeric",
"id": "20cf4756-40b0-4cc1-acb5-861765370a41"
},
"code": "29463-7",
"name": "Weight",
"id": "c0a8007b-6759-111d-8167-59e8dabe0086"
},
"id": "c0a8007b-6855-1d16-8168-5fd18fa301b7"
}}
}}
getting 1547795650562 and c0a8007b-6759-111d-8167-59e8dabe0086 as class names. But I dont want like this;
class DataList : NSObject, NSCoding{
var 1547795650562 : 1547795650562!
}
class 1547795650562 : NSObject, NSCoding{
var c0a8007b6759111d816759e8dabe0086 : VitalParameter!
}
But the problem here is, 1547795650562 and c0a8007b-6759-111d-8167-59e8dabe0086 cannot be hard coded because they may change.
c0a8007b-6759-111d-8167-59e8dabe0086 is dynamic id and 1547795650562 is recordDate. Inner object is repetitive.
But I have to map as the keys are of recordDate and id respectively.
Try using Codable instead of NSCoding to parse your JSON data.
Models:
struct Root: Codable {
let dataList: [String:[String:Record]]
}
struct Record: Codable {
let recordDate: Int
let resultValue: String
let vitalParameter: VitalParameter
let id: String
}
struct VitalParameter: Codable {
let uom, resultType: ResultType
let code, name, id: String
}
struct ResultType: Codable {
let code, name, id: String
}
Parse the JSON data using above models like,
do {
let response = try JSONDecoder().decode(Root.self, from: data)
print(response)
} catch {
print(error)
}
Note: You can use https://app.quicktype.io to get the models from your JSON instantly. Make the changes as per your requirement and you're good to go.
I have to decode this type of JSON that is downloaded by a response.
The JSON is this, I need retrieve the "gallery" of all items
JSON: https://pastebin.com/KnEwZzxd
I have tried many solution but I am not able to create a Decode of this son.
I have posted the full code on pastebin, too.
{
"status": 200,
"data": {
"date": "2018-07-29T00:00:00.300Z",
"featured": [
{
"id": "5b56298d781e197186378f50",
"name": "Sun Tan Specialist",
"price": "1,500",
"priceIcon": "vbucks",
"priceIconLink": "https://image.fnbr.co/price/icon_vbucks.png",
"images": {
"icon": "https://image.fnbr.co/outfit/5b56298d781e197186378f50/icon.png",
"png": "https://image.fnbr.co/outfit/5b56298d781e197186378f50/png.png",
"gallery": "https://image.fnbr.co/outfit/5b56298d781e197186378f50/gallery.jpg",
"featured": "https://image.fnbr.co/outfit/5b56298d781e197186378f50/featured.png"
},
"rarity": "epic",
"type": "outfit",
"readableType": "Outfit"
},
{
"id": "5b562af2781e19db65378f5c",
"name": "Rescue Paddle",
"price": "800",
"priceIcon": "vbucks",
"priceIconLink": "https://image.fnbr.co/price/icon_vbucks.png",
"images": {
"icon": "https://image.fnbr.co/pickaxe/5b562af2781e19db65378f5c/icon.png",
"png": "https://image.fnbr.co/pickaxe/5b562af2781e19db65378f5c/png.png",
"gallery": "https://image.fnbr.co/pickaxe/5b562af2781e19db65378f5c/gallery.jpg",
"featured": false
},
"rarity": "rare",
"type": "pickaxe",
"readableType": "Pickaxe"
}
],
"daily": [
{
"id": "5ab1723e5f957f27504aa502",
"name": "Rusty Rider",
"price": "1,200",
"priceIcon": "vbucks",
"priceIconLink": "https://image.fnbr.co/price/icon_vbucks.png",
"images": {
"icon": "https://image.fnbr.co/glider/5ab1723e5f957f27504aa502/icon.png",
"png": "https://image.fnbr.co/glider/5ab1723e5f957f27504aa502/png.png",
"gallery": "https://image.fnbr.co/glider/5ab1723e5f957f27504aa502/gallery.jpg",
"featured": "https://image.fnbr.co/glider/5ab1723e5f957f27504aa502/featured.png"
},
"rarity": "epic",
"type": "glider",
"readableType": "Glider"
},
{
"id": "5b0e944bdb94f1a4bbc0a8e4",
"name": "Rambunctious",
"price": "500",
"priceIcon": "vbucks",
"priceIconLink": "https://image.fnbr.co/price/icon_vbucks.png",
"images": {
"icon": "https://image.fnbr.co/emote/5b0e944bdb94f1a4bbc0a8e4/icon.png",
"png": "https://image.fnbr.co/emote/5b0e944bdb94f1a4bbc0a8e4/png.png",
"gallery": "https://image.fnbr.co/emote/5b0e944bdb94f1a4bbc0a8e4/gallery.jpg",
"featured": false
}
]
}
}
Aside from posting the JSON Code itself, it would be useful to actually show an attempt as to how you have attempted to decode it as well ^_________^.
Anyway, the best way to tackle this issue is to use custom Structs and the Decodable Protocol to handle the JSON response.
From your JSON you will initially get a two values:
/// The Initial Response From The Server
struct Response: Decodable {
let status: Int
let data: ResponseData
}
From this we then map the 'data' to a struct called ResponseData:
/// The Data Object
struct ResponseData: Decodable{
let date: String
let featured: [Product]
let daily: [Product]
}
In this we have two variables which contain an array of identical struct which I have called Product:
/// The Product Structure
struct Product: Decodable{
let id: String
let name: String
let price: String
let priceIcon: String
let priceIconLink: String
let images: ProductImages
let rarity: String
let type: String
let readableType: String
}
Within this we have one variable which is a dictionary (images) which we then map to another struct:
/// The Data From The Product Images Dictionary
struct ProductImages: Decodable{
let icon: String
let png: String
let gallery: String
///The Featured Variable For The Product Images Can Contain Either A String Or A Boolean Value
let featured: FeaturedType
}
The issue you have with the ProductImages, is that the featured var sometimes contains a String but on others it contains a Bool value. As such we need to create a custom struct to handle the decoding of this to ensure we always get a String (I am probably not doing this right way so if someone has a better solution please say so):
/// Featured Type Returns A String Of Either The Boolean Value Or The Link To The JPG
struct FeaturedType : Codable {
let formatted: String
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
do {
//1. If We Get A Standard Response We Have A String
let stringResult = try container.decode(String.self)
formatted = stringResult
} catch {
//2. On Occassions We Get An Bool
let boolResult = try container.decode(Bool.self)
formatted = String(boolResult)
}
}
}
Now that is the basic structure of your JSON so now you need to handle it. In this example I am loading the JSON from the MainBundle as I dont have the actual URL.
/// Loads & Decodes The JSON File
func retreiveJSON(){
//1. Load The JSON File From The Main Bundle
guard let jsonURL = Bundle.main.url(forResource: "sample", withExtension: ".json") else { return }
do{
//2. Get The Data From The URL
let data = try Data(contentsOf: jsonURL)
//3. Decode The JSON
let jsonData = try JSONDecoder().decode(Response.self, from: data)
//4. Extract The Data
extractDataFrom(jsonData)
}catch{
print("Error Processing JSON == \(error)")
}
}
In the above function you will notice I am calling the function extractDataFrom() which allows you to then do what you need to do with your data:
/// Extracts The Daily & Featured Products From The JSON
///
/// - Parameter jsonData: Response
func extractDataFrom(_ jsonData: Response){
//1. Get The Daily Products
let dailyProducts = jsonData.data.daily
dailyProducts.forEach { (product) in
print(product.id)
print(product.name)
print(product.price)
print(product.priceIcon)
print(product.priceIconLink)
print(product.images)
print(product.rarity)
print(product.type)
print(product.readableType)
}
//2. Get The Featured Products
let featuredProducts = jsonData.data.featured
featuredProducts.forEach { (product) in
print(product.id)
print(product.name)
print(product.price)
print(product.priceIcon)
print(product.priceIconLink)
print(product.images)
print(product.rarity)
print(product.type)
print(product.readableType)
}
}
If you wanted to save this data then all you would need to do is add the following variables under your class declaration e.g:
var featuredProducts = [Product]()
var dailyProducts = [Product]()
And in the extractDataFrom() function change the:
let dailyProducts
let featuredProducts
To:
dailyProducts = jsonData.data.daily
featuredProducts = jsonData.data.featured
Please note that this is a very crude example, and as noted, I may not be handling the 'featured' variable correctly.
Hope it helps...
Thanks to quicktype and other services converting valid json to Swift and other languages is simple. Editing it to fit your needs should be simple enough.
// To parse the JSON, add this file to your project and do:
//
// let welcome = try? JSONDecoder().decode(Welcome.self, from: jsonData)
import Foundation
struct Welcome: Codable {
let status: Int
let data: DataClass
}
struct DataClass: Codable {
let date: String
let featured, daily: [Daily]
}
struct Daily: Codable {
let id, name, price, priceIcon: String
let priceIconLink: String
let images: Images
let rarity, type, readableType: String?
}
struct Images: Codable {
let icon, png, gallery: String
let featured: Featured
}
enum Featured: Codable {
case bool(Bool)
case string(String)
init(from decoder: Decoder) throws {
let container = try decoder.singleValueContainer()
if let x = try? container.decode(Bool.self) {
self = .bool(x)
return
}
if let x = try? container.decode(String.self) {
self = .string(x)
return
}
throw DecodingError.typeMismatch(Featured.self, DecodingError.Context(codingPath: decoder.codingPath, debugDescription: "Wrong type for Featured"))
}
func encode(to encoder: Encoder) throws {
var container = encoder.singleValueContainer()
switch self {
case .bool(let x):
try container.encode(x)
case .string(let x):
try container.encode(x)
}
}
}