Swift 3 & JSON – How to edit data received from the database? - json

Question

This is a simple question of how-to. I don't know (and can't figure out on my own) what the correct terminology is for "editing" the data received from the JSON code. Here's my current code:
// Create a url and a session to load it in the background.
let url = URL(string: "http://api.fixer.io/latest")
let task = URLSession.shared.dataTask(with: url!) { (data, response, error) in
if error == nil {
// Try to extract some content from the data.
if let content = data {
do {
// Try to create an array out of the extracted data content.
let jsonResult = try JSONSerialization.jsonObject(with: content, options: JSONSerialization.ReadingOptions.mutableContainers) as AnyObject
// Search for specific objects in the array.
if let rates = jsonResult["rates"] as? NSDictionary {
print("Rates: \(rates)\n\n")
if let currency = rates["USD"] {
// Output of line below is – "Currency: \"1.0893\""
print("Currency: \(currency)")
}
}
} catch {
print("Error deserializing the JSON:\n\(String(describing: error))")
}
}
} else {
print("Error creating the URLSession:\n\(String(describing: error))")
}
}
// Begin using the URLSession to extract the data.
task.resume()
As you can see above, I am getting some data from a url using JSON, and then extracting a specific set of data which I'm titling rates and currency.
However, I can't find anywhere on the web for how to edit data. For example: let's say I want to change the value of currency to be equal to "$230" instead of "1.0893." What is the term/code necessary to go in and change that? Another example would be if I wanted to add another object into the rates Dictionary. What if I wanted to add "MyCurrency: true", or something like that? I'm not knowledgeable of the specific syntax on this. I need help!
EDIT – Yes, I am trying to change the database itself, that way when the information is pulled from it later on, it is updated with the changes I make now. In my above example, I said I could change currency to "$230." Well, I want it to permanently stay that way in the database, so that when I extract its value later, instead of still being "1.0893," it's now the value I changed it to.
Is this term "pushing?" I would like to make changes to the database itself.

Answer 1

Parse the JSON into a custom struct or class, for example
struct Currency {
let abbrev : String
var value : Double
var myCurrency : Bool
var dictionaryRepresentation : [String:Any] {
return ["abbrev" : abbrev, "value" : value, "myCurrency" : myCurrency]
}
}
var currencies = [Currency]()
The abbrev member is a constant (let), the other members are variables.
...
// Try to create an array out of the extracted data content.
let jsonResult = try JSONSerialization.jsonObject(with: content) as! [String:Any]
if let rates = jsonResult["rates"] as? [String:Double] {
for (abbrev, value) in rates {
let myCurrency = abbrev == "USD"
currencies.append(Currency(abbrev: abbrev, value: value, myCurrency: myCurrency))
}
}
The code uses native Dictionary. And .mutableContainers is useless in Swift anyway.