structure for Decodable JSON - json

Question

I am trying to put the following API link into a Decodable JSON in Swift
Link Here
Below is the code to map the link:
import Foundation
struct SelectedCompany: Decodable {
let LastTradePrice: Double
let ListedCompanyID: String
let ListedCompanyName: String
let MarketTotalOrdersByOrder: Int
let MarketTotalOrdersByPrice: Int
let MarketTotalSharesByOrder: Int
let MarketTotalSharesByPrice: Int
let NumberOfTrades: Int
let Value: Int
let Volume: Int
let MarketAskOrdersByOrder: [Order]
let MarketAskOrdersByPrice: [Order]
let MarketBidOrdersByOrder: [Order]
let MarketBidOrdersByPrice: [Order]
let VWAP: Int
}
struct Order: Decodable {
let Price: Double
let Shares: Int
}
Any idea why is not mapping correctly? When I try to run it in the simulator, I am getting the below error
dataCorrupted(Swift.DecodingError.Context(codingPath: [], debugDescription: "The given data was not valid JSON.", underlyingError: Optional(Error Domain=NSCocoaErrorDomain Code=3840 "JSON text did not start with array or object and option to allow fragments not set." UserInfo={NSDebugDescription=JSON text did not start with array or object and option to allow fragments not set.})))
Thanks
Post Edit:
The error comes when I run the below function in a separate class called Service:
class Service {
static func getSpecificCompany(companyID: String, table: UITableView, completion: #escaping (SelectedCompany) -> ()) {
let link = "https://www.adx.ae/en/_vti_bin/ADX/svc/trading.svc/ListedCompanyOrderBook?listedCompanyID=\(companyID)"
guard let url = URL(string: link) else { return }
URLSession.shared.dataTask(with: url) { (data, response, error) in
guard let resultData = data else { return }
do {
let resultCompany = try JSONDecoder().decode(SelectedCompany.self, from: resultData)
DispatchQueue.main.async {
completion(resultCompany)
table.reloadData()
}
} catch {
print(error)
}
}.resume()
}
}
In the ViewController class, the above function will be as follows:
class SomeViewController: UIViewController {
#IBOutlet weak var myTable: UITableView!
var selectedCompany:[SelectedCompany]?
var companyID = String()
override func viewDidLoad() {
super.viewDidLoad()
Service.getSpecificCompany(companyID: companyID, table: myTable) { (company) in
self.selectedCompany = company
}
}
}

Answer 1

The only problem with your structs is the presence of this sort of thing in the JSON:
{"Price":null,"Shares":null}
To cope with that, you need to rewrite your Order struct to allow for null:
struct Order: Decodable {
let Price: Double?
let Shares: Int?
}
As soon as I do that, I can successfully decode the JSON you showed using your SelectedCompany and Order.
Here is playground code that tests (successfully):
let json = """
{"LastTradePrice":3.87,"ListedCompanyID":"ADIB","ListedCompanyName":"Abu Dhabi Islamic Bank","MarketAskOrdersByOrder":[{
"Price":3.87,"Shares":100000},{
"Price":3.88,"Shares":100000},{
"Price":3.88,"Shares":6000},{
"Price":3.89,"Shares":100000},{
"Price":3.9,"Shares":30000},{
"Price":3.9,"Shares":100000},{
"Price":3.98,"Shares":99800},{
"Price":3.98,"Shares":10000},{
"Price":3.99,"Shares":75000},{
"Price":3.99,"Shares":285018},{
"Price":4,"Shares":100000},{
"Price":4,"Shares":100000},{
"Price":4,"Shares":10000},{
"Price":4,"Shares":6336},{
"Price":4,"Shares":100000},{
"Price":4.09,"Shares":5000},{
"Price":4.1,"Shares":50000},{
"Price":4.11,"Shares":5000},{
"Price":4.13,"Shares":28894},{
"Price":4.13,"Shares":25000}],"MarketAskOrdersByPrice":[{
"Price":3.87,"Shares":100000},{
"Price":3.88,"Shares":106000},{
"Price":3.89,"Shares":100000},{
"Price":3.9,"Shares":130000},{
"Price":3.98,"Shares":109800},{
"Price":3.99,"Shares":360018},{
"Price":4,"Shares":316336},{
"Price":4.09,"Shares":5000},{
"Price":4.1,"Shares":50000},{
"Price":4.11,"Shares":5000},{
"Price":4.13,"Shares":53894},{
"Price":4.14,"Shares":193000},{
"Price":4.15,"Shares":85000},{
"Price":4.2,"Shares":127211},{
"Price":4.25,"Shares":250000},{
"Price":4.26,"Shares":10000}],"MarketBidOrdersByOrder":[{
"Price":3.85,"Shares":5349},{
"Price":3.85,"Shares":200000},{
"Price":3.84,"Shares":70000},{
"Price":3.84,"Shares":300000},{
"Price":3.83,"Shares":75000},{
"Price":3.81,"Shares":28000},{
"Price":3.8,"Shares":700000},{
"Price":3.79,"Shares":100000},{
"Price":3.79,"Shares":10000},{
"Price":3.72,"Shares":50000},{
"Price":3.68,"Shares":100000},{
"Price":3.67,"Shares":15000},{
"Price":3.67,"Shares":25000},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null}],"MarketBidOrdersByPrice":[{
"Price":3.85,"Shares":205349},{
"Price":3.84,"Shares":370000},{
"Price":3.83,"Shares":75000},{
"Price":3.81,"Shares":28000},{
"Price":3.8,"Shares":700000},{
"Price":3.79,"Shares":110000},{
"Price":3.72,"Shares":50000},{
"Price":3.68,"Shares":100000},{
"Price":3.67,"Shares":40000},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null},{
"Price":null,"Shares":null}],"MarketTotalOrdersByOrder":28,"MarketTotalOrdersByPrice":16,"MarketTotalSharesByOrder":1678349,"MarketTotalSharesByPrice":1678349,"NumberOfTrades":41,"VWAP":0,"Value":7159043,"Volume":1863558}
"""
let jsondata = json.data(using: .utf8)
struct SelectedCompany: Decodable {
let LastTradePrice: Double
let ListedCompanyID: String
let ListedCompanyName: String
let MarketTotalOrdersByOrder: Int
let MarketTotalOrdersByPrice: Int
let MarketTotalSharesByOrder: Int
let MarketTotalSharesByPrice: Int
let NumberOfTrades: Int
let Value: Int
let Volume: Int
let MarketAskOrdersByOrder: [Order]
let MarketAskOrdersByPrice: [Order]
let MarketBidOrdersByOrder: [Order]
let MarketBidOrdersByPrice: [Order]
let VWAP: Int
}
struct Order: Decodable {
let Price: Double?
let Shares: Int?
}
do {
let result = try JSONDecoder().decode(SelectedCompany.self, from: jsondata!)
print(result) // works fine
} catch {
print(error) // no error
}