why is my json returning nil - json

Question

let myUrl = URL(string: "http://app.avatejaratsaba1.com/api/Values/GetPriceList?paymentType=1&goodType=102")
var request = URLRequest(url: myUrl!)
request.httpMethod = "GET" // compose a query string
request.addValue("application/json", forHTTPHeaderField: "content-type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
let task = URLSession.shared.dataTask(with: request)
{
(data : Data? , response : URLResponse? , error : Error?) in
self.removeActivtyIndicator(activityIndicator: MyActivityIndicator)
if error != nil
{
self.DisplayMessage(UserMessage: "2Could not successfully perform this request , please try again later.")
print("error = \(String(describing : error))")
}
// let's convert response sent from a server side code to a NSDictionary object:
do { let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as? NSDictionary
if let parseJSON = json
{
I have the exact code in another viewcontroller with another url and it works properly !!! it works properly in Postman!!
and i'm coding swift
UPDATED::::
do {
if let json = try JSONSerialization.jsonObject(with: data) as? [[String:Any]] {
var goodNameArray = [String].self
for i in 0..<json.count{
guard let goodName = json[i]["goodName"] as? String else{return}
Global.GlobalVariable.GoodName = goodNameArray.append(goodName)
}
print("GoodNames: \(goodNameArray)")
}
} catch let parseError {
print("parsing error: \(parseError)")
let responseString = String(data: data, encoding: .utf8)
print("raw response: \(String(describing: responseString))")
}
}
task.resume()
and the error it returns is :
Cannot invoke 'append' with an argument list of type '(String)'
global var code:::::
class Global: UIViewController
{
struct GlobalVariable
{
static var companyName = "Company"
static var bigName = ((0) , (""))
static var names = ["Loading..." , ""]
////////////
static var AgentInfo = "agentinfo"
////////////
static var genaral_goodID = 000
static var GoodName = [String]()
static var PriceVariableName = "PriceVariableName"
static var paymentType = "paymentType"
static var fee = "fee"
static var exipreDate = "exipreDate"
static var expireTime = "expireTime"
}
}
UPDATED::::::
uitable
class secondtable : TableViewController
{
override func numberOfSections(in tableView: UITableView) -> Int {
return 1
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return Global.GlobalVariable.names.count
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = UITableViewCell()
let content = Global.GlobalVariable.GoodName[indexPath.row]
cell.textLabel?.text = content
//cell.accessoryType = .disclosureIndicator
return cell
}
}
here in this par of my code , i'm supposed to populate a table with "goodName"

Answer 1

I tested in bellow way ,it is working for me.The response in array of dictionaries. Don't do force unwrap.
func viewDidLoad(){
downloadDataFromServer { (success, goodNamesArray) in
if success{
print("goodNamesArray: \(goodNamesArray)")
print("successfully updated tableview data")
self.tableView.reloadData()
}
}
}
func downloadDataFromServer(completionHandler: #escaping(Bool,[String])->()){
guard let url = URL(string: "http://app.avatejaratsaba1.com/api/Values/GetPriceList?paymentType=1&goodType=102") else {
return
}
let request = URLRequest(url: url)
let task = URLSession.shared.dataTask(with: request) { data, response, error in
guard let data = data else {
print("request failed \(String(describing: error))")
return
}
do {
if let json = try JSONSerialization.jsonObject(with: data) as? [[String:Any]] {
var goodNameArray = [String]()
for i in 0..<json.count{
guard let goodName = json[i]["goodName"] as? String else{return}
self.goodNameArray.append(goodName)
}
print("GoodNames: \(self.goodNameArray)")
Global.GlobalVariable.GoodName = goodNameArray
}
} catch let parseError {
print("parsing error: \(parseError)")
let responseString = String(data: data, encoding: .utf8)
print("raw response: \(String(describing: responseString))")
}
}
task.resume()
}

Answer 2

Do yourself a favour and save some time by reading up on the Codable protocol. It will allow you to generate a pretty decent JSON-parser by basically just defining your structure. Using JSONDecoder.decode will provide you with much more valuable error information if something goes wrong.
Since your API is currently only providing an empty array using the URL you provide us with it is pretty hard to come up with any meaningful code. You should resort to a simple String-representation of your JSON, at least a minimalized form that shows us all about the structure. That way your question would not depend on the workings of a probably fairly complicated web service.