Error while trying to updat API with button click - json

Question

I'm trying to update API values with a button click. This is the update function:
func updateAPI() {
withAnimation {
model.allStocks = []
for stock in depot.aktienKatArray {
model.getStockData(for: stock.aKat_symbol ?? "")
for allS in model.allStocks {
if allS.metaData.symbol == stock.aKat_symbol {
stock.aKat_currPerShare = Double(allS.latestClose) ?? 0
}
}
}
PersistenceController.shared.saveContext()
}
}
I'm using two for .. in loops to assign the api value (latestClose) to the corresponding stock in the AktieKat Entity.
The view has an update button at the top and a list of stocks with the attribute aKat_currPerShare and every time I update the API (with button click) the aKat_currPerShare should get the updated latestClose value of the API.
The error message from the output in Xcode appears when the button is clicked:
keyNotFound(CodingKeys(stringValue: "Meta Data", intValue: nil), Swift.DecodingError.Context(codingPath: [], debugDescription: "No value associated with key CodingKeys(stringValue: "Meta Data", intValue: nil) ("Meta Data").", underlyingError: nil))
This is my API Model:
final class APIModel: ObservableObject {
#Environment(\.managedObjectContext) private var viewContext
#Published var allStocks: [StockData] = []
private var cancellables = Set<AnyCancellable>()
#Published var stockEntities: [AktieKat] = []
init() {
loadAllStocks()
}
func loadAllStocks() {
allStocks = []
stockEntities.forEach { stockEntity in
getStockData(for: stockEntity.aKat_symbol ?? "")
}
}
func getStockData(for symbol: String) {
let url = URL(string: "https://www.alphavantage.co/query?function=TIME_SERIES_DAILY&symbol=\(symbol)&outputsize=full&apikey=\(APIKEY ?? "E11H9EDJNUB2N1UJ")")!
URLSession.shared.dataTaskPublisher(for: url)
.tryMap { element -> Data in
guard let response = element.response as? HTTPURLResponse,
response.statusCode == 200 else {
throw URLError(.badServerResponse)
}
return element.data
}
.decode(type: StockData.self, decoder: JSONDecoder())
.sink { completion in
switch completion {
case .failure(let error):
print(error)
return
case .finished:
return
}
} receiveValue: { [unowned self] returnedStocks in
DispatchQueue.main.async {
self.allStocks.append(returnedStocks)
}
}
.store(in: &cancellables)
}
}
and these are the CodingKeys:
struct StockData: Codable {
var metaData: MetaData
var timeSeriesDaily: [String: TimeSeriesDaily]
// var latestClose: String {
// timeSeriesDaily.first?.value.close ?? ""
// }
var latestClose: String {
guard let mostRecentDate = timeSeriesDaily.keys.sorted(by: >).first else { return "" }
return timeSeriesDaily[mostRecentDate]!.close
}
private enum CodingKeys: String, CodingKey {
case metaData = "Meta Data"
case timeSeriesDaily = "Time Series (Daily)"
}
struct MetaData: Codable {
let information: String
let symbol: String
let lastRefreshed: String
let outputSize: String
let timeZone: String
private enum CodingKeys: String, CodingKey {
case information = "1. Information"
case symbol = "2. Symbol"
case lastRefreshed = "3. Last Refreshed"
case outputSize = "4. Output Size"
case timeZone = "5. Time Zone"
}
}
struct TimeSeriesDaily: Codable {
var open: String
var high: String
var low: String
var close: String
var volume: String
private enum CodingKeys: String, CodingKey {
case open = "1. open"
case high = "2. high"
case low = "3. low"
case close = "4. close"
case volume = "5. volume"
}
}
}
{
"Meta Data": {
"1. Information": "Daily Prices (open, high, low, close) and Volumes",
"2. Symbol": "DAI.DEX",
"3. Last Refreshed": "2022-04-05",
"4. Output Size": "Full size",
"5. Time Zone": "US/Eastern"
},
"Time Series (Daily)": {
"2022-04-05": {
"1. open": "64.4900",
"2. high": "64.8200",
"3. low": "62.6200",
"4. close": "62.9600",
"5. volume": "3425810"
},
"2022-04-04": {
"1. open": "63.9900",
"2. high": "64.5400",
"3. low": "62.8100",
"4. close": "64.2600",
"5. volume": "2538008"
}
}

Answer 1

Here is my test code to fetch stocks using Swift async/await concurrency framework (just for fun).
I know you said I'm not that experienced in swift, and
it will be heavy to understand at first. But learning how to use it pays off later on,
especially in this case, where you want to download a lot of info using a lot of network calls. Hope it helps, if not let me know and I'll delete my answer.
See also:
https://developer.apple.com/documentation/swift/updating_an_app_to_use_swift_concurrency
https://developer.apple.com/news/?id=2o3euotz
import Foundation
import SwiftUI
struct StockData: Identifiable, Codable {
let id = UUID() // <-- here
var metaData: MetaData?
var timeSeriesDaily: [String: TimeSeriesDaily]?
var latestClose: String {
if let timeseries = timeSeriesDaily {
guard let mostRecentDate = timeseries.keys.sorted(by: >).first else { return "" }
return timeseries[mostRecentDate]!.close
} else {
return ""
}
}
private enum CodingKeys: String, CodingKey {
case metaData = "Meta Data"
case timeSeriesDaily = "Time Series (Daily)"
}
}
struct MetaData: Codable {
let information: String
let symbol: String
let lastRefreshed: String
let outputSize: String
let timeZone: String
private enum CodingKeys: String, CodingKey {
case information = "1. Information"
case symbol = "2. Symbol"
case lastRefreshed = "3. Last Refreshed"
case outputSize = "4. Output Size"
case timeZone = "5. Time Zone"
}
}
struct TimeSeriesDaily: Codable {
var open: String
var high: String
var low: String
var close: String
var volume: String
private enum CodingKeys: String, CodingKey {
case open = "1. open"
case high = "2. high"
case low = "3. low"
case close = "4. close"
case volume = "5. volume"
}
}
// for testing
struct AktieKat: Identifiable, Codable {
let id = UUID() // <-- here
var aKat_symbol: String?
var aKat_currPerShare: Double?
private enum CodingKeys: String, CodingKey {
case aKat_symbol, aKat_currPerShare
}
}
final class APIModel: ObservableObject {
#Environment(\.managedObjectContext) private var viewContext
let apikey = "E11H9EDJNUB2N1UJ"
#Published var allStocks: [StockData] = []
#Published var stockEntities: [AktieKat] = []
init() {
// for testing
self.stockEntities = [AktieKat(aKat_symbol: "AAP"), AktieKat(aKat_symbol: "MSFT")]
Task {
await loadAllStocks()
}
}
func loadAllStocks() async {
Task{#MainActor in
allStocks = await loadAllStocks(for: stockEntities)
}
}
// fetch all StockData concurrently
func loadAllStocks(for arr: [AktieKat]) async -> [StockData] {
var results: [StockData] = []
// get all stocks concurrently
await withTaskGroup(of: (StockData?).self) { group -> Void in
arr.forEach { stockEntity in
group.addTask {
await (self.getStockData(for: stockEntity.aKat_symbol))
}
}
for await value in group {
if let stock = value {
results.append(stock)
}
}
}
return results
}
// fetch one StockData for one symbol
func getStockData(for theSymbol: String?) async -> StockData? {
if let symbol = theSymbol,
let url = URL(string: "https://www.alphavantage.co/query?function=TIME_SERIES_DAILY&symbol=\(symbol)&outputsize=full&apikey=\(apikey)") {
do {
let (data, _) = try await URLSession.shared.data(from: url)
return try JSONDecoder().decode(StockData.self, from: data)
}
catch { print(error) }
}
return nil
}
}
struct ContentView: View {
#StateObject var apiModel = APIModel()
// for testing
#State var depot_aktienKatArray = [AktieKat(aKat_symbol: "IBM")]
var body: some View {
VStack (spacing: 33){
Button("update") {
updateAPI()
}.buttonStyle(.bordered).padding(20)
if apiModel.allStocks.count == 0 {
ProgressView()
} else {
Text("\(apiModel.allStocks.count) stocks fetched")
}
List(apiModel.allStocks) { stock in
HStack (spacing: 20) {
Text(stock.metaData?.symbol ?? "no data")
Text(stock.latestClose).foregroundColor(.red)
}
}
}
}
// not sure what you want to do here
func updateAPI() {
withAnimation {
Task {#MainActor in
apiModel.allStocks = []
apiModel.allStocks = await apiModel.loadAllStocks(for: depot_aktienKatArray)
for stock in apiModel.allStocks {
if let index = depot_aktienKatArray.firstIndex(where: {$0.aKat_symbol == stock.metaData.symbol}) {
depot_aktienKatArray[index].aKat_currPerShare = Double(stock.latestClose) ?? 0
}
}
// PersistenceController.shared.saveContext()
}
}
}
}