JSON using Swift 4 - json

Question

First of all, my question may have already been asked but I search on many tutorial and forums and I can't make it works because I'm french and not very good in English.
I try to read JSON with my app but It doesn't work. The only thing printed is "Foundation.JSONDecoder"
This is my SWIFT 4 code :
func getSpots(){
guard let downloadURL = URL(string: "http://dronespot.fr/getSpot.php") else { return }
URLSession.shared.dataTask(with: downloadURL) { data, urlResponse, error in
guard let data = data, error == nil, urlResponse != nil else {
print("Oops Call for Help")
return
}
print("downloaded")
do
{
let decoder = JSONDecoder()
//let rates = try decoder.decode([Artwork].self, from: data)
print(decoder)
} catch {
print("Error after loading")
}
}.resume()
}
Artwork.swift :
init?(json: [Any]) {
// 1
self.title = json[16] as? String ?? "No Title"
self.locationName = json[12] as! String
self.id = 3
self.img = "tamere"
// 2
if let latitude = Double(json[18] as! String),
let longitude = Double(json[19] as! String) {
self.coordinate = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
} else {
self.coordinate = CLLocationCoordinate2D()
}
}
Expected JSON :
http://dronespot.fr/getSpot.php
Thanks for your help

Answer 1

Since you want to use JSONDecoder your approach is completely wrong (apart from the issue that you commented out the actual line to decode the JSON).
Create Artwork as a struct adopting Decodable, declare the keys in the JSON as properties and add a lazy instantiated variable to build the coordinate:
struct Artwork : Decodable {
let nom : String
let description : String
let id: String
let img1 : String
let latitude : String
let longitude : String
// there are much more keys
lazy var coordinate : CLLocationCoordinate2D = {
return CLLocationCoordinate2D(latitude: Double(latitude) ?? 0.0, longitude: Double(longitude) ?? 0.0)
}()
}
Now decode the array of Artwork
do {
let decoder = JSONDecoder()
let rates = try decoder.decode([Artwork].self, from: data)
print(rates)
} catch {
print("Error after loading", error)
}