How to access JSON data from URL in Swift 5 - json

Question

I'm creating a list of data from a JSON list from a website. However, URLSession.shared.dataTask is returning empty data.
I've tried printing outside the function of URLSession.shared.dataTask, JSONSerilization, JSONDecoder, Different forms of URLs
I've been working on this for almost a week and I still can't figure out what's the issue. My main guess right now is that it's because I'm printing inside the function, but from tutorials online I see that they all print inside.
Any help will be greatly appreciated! :)
if let url = URL(string: urlString.addingPercentEncoding(withAllowedCharacters: .urlQueryAllowed)!){
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let data = data else {
print("Data != Data")
return
}
let dataStr = String(decoding: data, as: UTF8.self)
print("DataStr" + dataStr) //Empty
do {
let dataParse = try? JSONDecoder().decode(OuterData.self, from: data)
let json = try JSONSerialization.jsonObject(with: data, options: .mutableContainers)
print(dataParse) //nil
print(json)//empty data
} catch let jsonError {
print ("jsonError")
print (jsonError)
}
}.resume()
//Created from https://app.quicktype.io/#l=go
struct Suggestion: Codable {
let id: String
let name: String
let audience_size: Int
let path = [String]()
let description: String?
let topic: Topic?
let disambiguation_category: String?
enum CodingKeys: String, CodingKey {
case id, name
case audience_size = "audience_size"
case path
case description = "description"
case topic
case disambiguation_category = "disambiguation_category"
}
}
struct OuterData: Codable{
let dataSuggestion: [Suggestion]
}
enum Topic: String, Codable {
case businessAndIndustry = "Business and industry"
case education = "Education"
case foodAndDrink = "Food and drink"
case hobbiesAndActivities = "Hobbies and activities"
case lifestyleAndCulture = "Lifestyle and culture"
case newsAndEntertainment = "News and entertainment"
case people = "People"
case shoppingAndFashion = "Shopping and fashion"
case sportsAndOutdoors = "Sports and outdoors"
case technology = "Technology"
case travelPlacesAndEvents = "Travel, places and events"
}
Expected Output:
{
"data": [
{
"id": "6008740787350",
"name": "Business and industry",
"audience_size": 1759626900,
"path": [
"Interests",
"Business and industry"
],
"description": ""
},
{
"id": "6003402305839",
"name": "Business",
"audience_size": 1231141110,
"path": [
"Interests",
"Business and industry",
"Business"
],
"description": "",
"topic": "Business and industry"
},
{
"id": "6003248297213",
"name": "Product (business)",
"audience_size": 935729470,
"path": [
"Interests",
"Additional Interests",
"Product (business)"
],
"description": null,
"topic": "Business and industry"
},
{
"id": "6004037932409",
"name": "Management",
"audience_size": 323096480,
"path": [
"Interests",
"Business and industry",
"Management"
],
"description": "",
"topic": "Business and industry"
},
{
"id": "6002840040679",
"name": "Music industry",
"audience_size": 251698230,
"path": [
"Interests",
"Additional Interests",
"Music industry"
],
"description": null,
"topic": "News and entertainment"
},
{
"id": "6002884511422",
"name": "Small business",
"audience_size": 87865033,
"path": [
"Interests",
"Business and industry",
"Small business"
],
"description": "",
"topic": "Business and industry"
},
{
"id": "6003165841322",
"name": "Distribution (business)",
"audience_size": 79327710,
"path": [
"Interests",
"Additional Interests",
"Distribution (business)"
],
"description": null,
"topic": "Business and industry"
},
{
"id": "6003342222945",
"name": "Show business",
"audience_size": 69642870,
"path": [
"Interests",
"Additional Interests",
"Show business"
],
"description": null,
"topic": "News and entertainment"
},
{
"id": "6002932439173",
"name": "Subscription business model",
"audience_size": 64490740,
"path": [
"Interests",
"Additional Interests",
"Subscription business model"
],
"description": null,
"topic": "Business and industry"
},
{
"id": "6003464157303",
"name": "Business Insider",
"audience_size": 62085690,
"path": [
"Interests",
"Additional Interests",
"Business Insider"
],
"description": null,
"topic": "Business and industry"
},
{
"id": "6003190330534",
"name": "Order (business)",
"audience_size": 60961920,
"path": [
"Interests",
"Additional Interests",
"Order (business)"
],
"description": null,
"topic": "Travel, places and events"
},
...
}

Answer 1

Simply replace
let dataSuggestion: [Suggestion]
with
let data: [Suggestion]
The names of the struct members must match the corresponding JSON keys unless you add CodingKeys.
And – as suggested in the comments – remove always the question mark in try? inside a do - catch block