Swift 4 - JSON parsing with Codable protocol (nested data) - ios

Question

I am trying to update myself and use modern and recent Swift 4 features.
That is why I am training with the Codable protocol in order to parse JSON and directly map my model object.
First of all, I did some research and self learning.
This article helped me a lot : Ultimate guide
I just need to focus on the "Com" array.
As you can notice, it contains some nested object. I named them Flash Info.
It is defined by :
endDate
text
image[]
title
productionDate
id
So here is my Codable Struct :
struct FlashInfo : Codable {
let productionDate: String
let endDate: String
let text: String
let title: String
let id: String
}
First of all, I was trying to parse it without the array of Images, I will handle it later.
So here is my method :
func getFlashInfo(success: #escaping (Array<FlashInfo>) -> Void) {
var arrayFlash = [FlashInfo]()
Alamofire.request(URL_TEST, method: .get).responseJSON { response in
if response.value != nil {
if let data = response.data, let utf8Text = String(data: data, encoding: .utf8) {
print("Data: \(utf8Text)")
}
//let decoder = JSONDecoder()
// let flash = try! decoder.decode(FlashInfo.self, from: response.data!)
// arrayFlash.append(flash)
success(arrayFlash)
} else {
print("error getFlashInfo")
}
}
}
I don't know how to handle the fact that I only need the "Com" array and how to iterate through all nested objects in order to fill my array in the callback.
I mean, will the decode protocol iterate through each objects ?
Am I clear?
EDIT: JSON as text
{"Test": [], "Toto": [], "Com": [{"endDate": "2017-06-27T08:00:00Z", "text": "John Snow is getting married", "image": ["895745-test.png", "632568-test.png"], "titre": "We need you!", "productionDate": "2017-07-02T16:16:23Z", "id": "9686"}, {"endDate": "2017-07-27T08:00:00Z", "text": "LOL TEST", "image": ["895545-test.png", "632568-test.png"], "titre": "She needs you!", "productionDate": "2017-08-02T16:16:23Z", "id": "9687"},{"endDate": "2017-06-27T08:00:00Z", "text": "iOS swift", "image": ["895775-test.png", "638568-test.png"], "titre": "They need you!", "productionDate": "2017-07-02T16:16:23Z", "id": "9688"}], "Yt": []}

Answer 1

I believe the quickest way is just to define an incomplete Response type as well. For instance:
struct Response: Codable {
let Com: [FlashInfo]
}
struct FlashInfo: Codable {
let productionDate: String
let endDate: String
let text: String
let title: String
let id: String
let image: [String] = [] // Ignored for now.
enum CodingKeys: String, CodingKey {
case productionDate, endDate, text, id
case title = "titre" // Fix for JSON typo ;)
}
}
and decode it like this:
let decoder = JSONDecoder()
let response = try! decoder.decode(Response.self, from: data)
print(response.Com)
This worked great with the test data you provided (just watch out for the typo in the title field):
let json = """
{"Test": [], "Toto": [], "Com": [{"endDate": "2017-06-27T08:00:00Z", "text": "John Snow is getting married", "image": ["895745-test.png", "632568-test.png"], "titre": "We need you!", "productionDate": "2017-07-02T16:16:23Z", "id": "9686"}, {"endDate": "2017-07-27T08:00:00Z", "text": "LOL TEST", "image": ["895545-test.png", "632568-test.png"], "titre": "She needs you!", "productionDate": "2017-08-02T16:16:23Z", "id": "9687"},{"endDate": "2017-06-27T08:00:00Z", "text": "iOS swift", "image": ["895775-test.png", "638568-test.png"], "titre": "They need you!", "productionDate": "2017-07-02T16:16:23Z", "id": "9688"}], "Yt": []}
"""
let data = json.data(using: .utf8)!