How to map [[String:AnyObject]] to a class from a string - ios

Question

I'm trying to add an Array of objects from a string. I am getting an encrypted string from an API call. After decrypting the data, getting as a string of JSON structure as below:
{
"request_id”:”abcds123”,
"status”:”18”,
"message":"SUCCESS",
"customer_name”:”XXXX X XX”,
"mobile_no”:”123456789”,
"email_id":"xxx#xxx.com",
“function”:
[
{“funcCode”:”OPN”,,”funcVal”:0,”funcType":"M"},
{“funcCode”:”CLO”,”funcVal”:1,”funcType":"M"}
],
“dataID”:”ASD1234”,
”valid”:”Y”
}
This is generic API response which will very based on response.
I can map "function" element to [[String:AnyObject]]. But not able to map it to class directly. Do we have an easier approach to extract "function" array to a class in swift without iterating the data and add to an array variable:
var mainObject : [String:Any] = [:]
if let data = result.data(using: .utf8) {
do {
mainObject = (try JSONSerialization.jsonObject(with: data, options: []) as? [String: Any])!
if let status = mainObject[“status”] as? String {
switch(status) {
case 200:
if mainObject.keys.contains(“customer_name”) {
//do something
}
if mainObject.keys.contains(“function”) {
if let functionList = mainObject[“function”] as? [[String:AnyObject]] {
//map functionList to class [Function]
for function in functionList {
print(“Function ====> ", function)
//create a class and add to an array of Function class
}
}
}
}
} catch {
print(error.localizedDescription)
}
}
}
The result string coming from response.
Objective is to extract "function" data alone and map it to class without creating container class/struct.

Answer 1

You can use the Codable protocol that will help you to map your JSON data into objects.
First create your structs:
struct MyFunction: Codable {
let funcCode: String
let funcVal: Int
let funcType: String
}
struct MyContainer: Codable {
let status: string,
let message: string,
// Another properties
let function: [MyFunction]
}
Then you just have to map your JSON string to the object using the decode function:
if let jsonData = result.data(using: .utf8) {
do {
let decoder = JSONDecoder()
let mainObject = try decoder.decode(MyContainer.self, for: jsonData)
} catch {
print(error.localizedDescription)
}
}
For more information you can check out this blog post.

Answer 2

State of the art is the (De)Codable protocol, you can decode JSON dictionaries directly into structs
struct Main: Decodable {
let status, customerName: String
let function : [Function]
}
struct Function: Codable {
let funcCode, funcType: String
let funcVal : Int
}
let data = Data(result.utf8)
do {
let decoder = JSONDecoder()
decoder.keyDecodingStrategy = .convertFromSnakeCase
let mainObject = try decoder.decode(Main.self, from: data)
print(mainObject.customerName)
print(mainObject.function)
} catch {
print(error)
}
Note: A JSON dictionary is never [String:AnyObject] in Swift 3+, it's [String:Any]
Edit: If you want only the Function struct keep the JSONSerialization code, omit the Main struct, declare mainObject as
var functions = [Function]()
and map the JSON array
if let functionList = mainObject["function"] as? [[String:Any]] {
functions = functionList.map {Function(funcCode: $0["funcCode"] as! String,
funcVal: $0["funcVal"] as! Int,
funcType: $0["funcType"] as! String) }
}
To write the array to UserDefaults encode it with JSONEncoder to Data.