How to avoid "Error Domain=NSCocoaErrorDomain Code=3840" in Swift? - ios

Question

I keep getting this particular error when trying to parse a JSON response in Swift:
Error Domain=NSCocoaErrorDomain Code=3840 "No value." UserInfo={NSDebugDescription=No value.}
Code:
let dict = [
"phone": phone,
"firstname": "\(String(describing: firstName))",
"lastname": "\(String(describing: lastName))"
]
as [String: Any]
if let jsonData = try? JSONSerialization.data(withJSONObject: dict, options: []) {
var request = URLRequest(url: URL(string: "\(config.baseURL)employee")!)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = jsonData
request.timeoutInterval = 30.0
let task = URLSession.shared.dataTask(with: request) { data, response, error in
if error != nil {
DispatchQueue.main.async {
self.alertController.singleButtonAlertController("Error", (error?.localizedDescription)!, self, self.defaultAction)
return
}
}
guard let data_ = data else {
return
}
do {
let jsonObj = try JSONSerialization.jsonObject(with: data_, options: .mutableContainers) as? NSDictionary
guard let parseJSON = jsonObj else {
return
}
self.navigationItem.rightBarButtonItem = self.rightBarButton
let meta = parseJSON["meta"] as? [String:Any]
let status = meta!["status"] as? String
if status == "200" {
isEmployeeModified = true
self.dismiss(animated: true, completion: nil)
} else {
let info = meta!["info"] as? String
let message = meta!["message"] as? String
DispatchQueue.main.async {
self.alertController.singleButtonAlertController(info!, message!, self, self.defaultAction)
}
}
} catch let error as NSError {
print(error)
}
}
task.resume()
I have used similar codes in other parts of the project and everything checks out.

Answer 1

According to this Error, the response from your server is not a valid JSON
Can you use responseString instead of responseJSON like below
Alamofire.request(URL, method: requestMethod, parameters: params).responseString{ response in
print(response)
}

Answer 2

I was able to figure out what was wrong and I'm going to explain this here for future readers. Apparently, I was doing a GET request the wrong way, so when I intend to do a POST request, for some reason, it still sees it as a GET request and that was why I kept getting the response: Error Domain=NSCocoaErrorDomain Code=3840 "No value." UserInfo={NSDebugDescription=No value.}
Below is my refactored code and it works without any hassle:
let dict = [
"phone": phone,
"firstname": firstName,
"lastname": lastName
] as [String : Any]
guard let jsonData = try? JSONSerialization.data(withJSONObject: dict, options: []) else {
return
}
guard let url = URL(string: "\(config.baseURL)employee") else {
return
}
var request = URLRequest(url: url)
request.httpMethod = "POST"
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = jsonData as Data
request.timeoutInterval = 10
let session = URLSession.shared
session.dataTask(with: request) { (data, response, error) in
if let response = response {
print("JSON Response: \(response)")
}
if error != nil {
DispatchQueue.main.async {
self.navigationItem.rightBarButtonItem = self.rightBarButton
self.alertController.singleButtonAlertController("Error", (error?.localizedDescription)!, self, self.defaultAction)
return
}
}
if let data = data {
do {
let parseJSON = try JSONSerialization.jsonObject(with: data, options: []) as? NSDictionary
let meta = parseJSON!["meta"] as? [String:Any]
let status = meta!["status"] as? String
if status == "200" {
isEmployeeModified = true
self.dismiss(animated: true, completion: nil)
} else {
let info = meta!["info"] as? String
let message = meta!["message"] as? String
DispatchQueue.main.async {
self.alertController.singleButtonAlertController(info!, message!, self, self.defaultAction)
}
}
} catch {
print(error)
}
}
}.resume()