JSON cannot get data into SQLite3 table - json

Question

I have seen quite a few posts on this question and none seem to answer my question. They are usually far more complicated than what I am asking. I have a list of one or more stocks that I would like to get the latest price for from the Internet. I found a nice API for doing that and was excited to create a simple structure and do the basics of a URLSession. I was able to pull the data into my structured format and print it in the console no problem. For example:
Quote(symbol: "C", companyName: "Citigroup Inc.", latestPrice: 68.86)
I want to update my SQLite3 database records with the current price. I cannot get the data out.
So I have my opentrades array based on a model:
class OpenTradeDur: NSObject {
#objc dynamic var trNo: Int
#objc dynamic var trPDate: String
#objc dynamic var trTicker: String
#objc dynamic var trDur: String
#objc dynamic var trCurPrice: Double
and the Quote structure is simple:
struct Quote: Decodable {
let symbol: String
let companyName: String
let latestPrice: Double
}
I have tried multiple variations of functions and actions and variables but my latest attempt that is still no closer to working is running in my viewDidLoad of my ViewController where I do some initial setup:
for _ in opentrades {
rn = rn + 1
let url = URL(string: "https://api.iextrading.com/1.0/stock/\(opentrades[rn].trTicker)/quote")
let session = URLSession.shared
let task = session.dataTask(with: url!) {(data, response, error) in
guard let data = data else { return }
do {
let quote = try JSONDecoder.decode(Quote.self,from: data)
print(quote)
self.opentrades[rn].trCurPrice = quote.latestPrice
} catch {}
}
task.resume()
}
I found a few posts that talk about completion handlers but even in those examples only give an answer that ends up printing to console. I just need a simple implementation. What I really need is a function that I can just call and say:
price = getPrice(stockTicker)
eg. price = getPrice("C")
and what that is doing behind the scenes if getting the JSON data from
https://api.iextrading.com/1.0/stock/C/quote
Can anyone point me in the right direction?
[2018-10-25]
I have managed to get this working in a fashion by creating a delegate protocol in the class I have performing the URLSession and then extending my ViewController with the delegate. And this works for a single quote at a time. I can initiate the process with a button and when the data comes back through the delegate's didLoad function I have it update the screen. But I was looking for a backend process to make multiple calls to the quote api and update multiple records. But I could not get that to synch up. But I had a thought and went back to the API documentation found a batch call where I can return all of the data for multiple stocks in one call. That is exactly what I need however I am stuck once again. The returned data is JSON data but not jsonapi.org compliant. I am going to post this as a new question and try hard to make sense in my asking of the question.
Edit: I received a great response from my new question and it has solved the problem I was experiencing here so I will provide an update.
As I tried to explain previously, my application runs through a list of open stock trades at startup and wants to update the latest price for each of them. I have an array I run through to set the price and then update my database to save those changes. Then my app opens with the new data in place.
I now have a function that takes a stock symbol as an input and returns the price immediately...
func getPrice(ticker: String) -> Double {
var price = 0.0
let urlString = "https://api.iextrading.com/1.0/stock/\(ticker)/quote"
let data = try! Data(contentsOf: URL(string: urlString)!)
do {
let response = try JSONDecoder().decode(Quote.self,from: data)
price = response.latestPrice
} catch let jsonErr { print("Error decoding JSON:",jsonErr)}
return price
}
I simply run through my array of trades and set the price...
opentrades[rn].trCurPrice = getPrice(ticker: opentrades[rn].trTicker)
I will be testing this to see how it works out without using a URLSession especially during the trading day and times of high activity and potential network latency.