Am I converting JSON data to a Swift variable the long way? - json

Question

I am reading json data from a file and trying to move it into a NSDictionary and I am wondering if there is a more concise way to do it. The code shown below works fine. In my program the Astruct-type variable has more than 25 Bstruct-type variables. I have several files similar to the one I show. So it leads to a lot of cumbersome programming.
import UIKit
struct Bstruct {
var label = String()
var inputTypeStr = String()
var list = [String]()
}
struct Astruct {
// in real situation this has a over 25 variables
// limited to 3 for this question
var number = Bstruct()
var customer = Bstruct()
var location = Bstruct()
}
func loadJson(forFilename fileName: String) -> NSDictionary? {
if let url = Bundle.main.url(forResource: fileName, withExtension: "json") {
if let data = NSData(contentsOf: url) {
do {
let dictionary = try JSONSerialization.jsonObject(with: data as Data, options: .allowFragments) as? NSDictionary
return dictionary
} catch {
print("Error!! Unable to parse \(fileName).json")
}
}
print("Error!! Unable to load \(fileName).json")
}
return nil
}
func fillAstruct (value: NSDictionary) -> Bstruct {
return Bstruct(label: value["label"] as! String, inputTypeStr: value["inputTypeStr"] as! String, list: value["list"] as! [String])
}
var aVar = Astruct()
let json = loadJson(forFilename: "document")! as NSDictionary
let d = json["aTemplate"]! as! NSDictionary
print("d = \(d)")
// load d into aVar, appears to be complex particularly if the variable has a large number of variables in aVar and the json file
for d1 in d {
let key = String(describing: d1.0)
let value = d1.1 as! NSDictionary
switch key {
case "number":
aVar.number = fillAstruct(value: value)
case "customer":
aVar.customer = fillAstruct(value: value)
case "location":
aVar.location = fillAstruct(value: value)
default: break
}
}
print("\(aVar)")
The JSON file is shown below:
{
"aTemplate": {
"number": {
"label": "Number",
"inputTypeStr": "selection",
"list": [
"A",
"B",
"C"
]
},
"customer": {
"label": "Customer",
"inputTypeStr": "label",
"list": [
""
]
},
"location": {
"label": "location",
"inputTypeStr": "label",
"list": [
""
]
}
}
}