Swift How to update (modify, Delete, Add) entries of JSON - ios

Question

Hello i need some help here, I'm making an IOS app that gets data from a JSON API and then showing the results on a Table , when i tap on a result from the table it goes to a second view controller where i'm showing the details. What I want to do is to update the info I'm showing on the details, delete entries from the JSON by deleting them from the table itself, and add a new entry to be saved on the JSON.
This is the JSON structure:
{
_id: "57eec6c9dfc2fb03005c0dd0",
ssid: "nonummy",
password: "accumsan",
lat: 29.39293,
lon: 115.71771,
summary: "curae nulla dapibus dolor vel est donec odio justo sollicitudin ut",
__v: 0,
likes: 1,
unlikes: 0,
bssid: "EF:CD:AB:56:34:12"
},
I want to be able to update the SSID, Password and Summary.
this is the code I'm using to get the Result from the JSON and is working good
Code:
let url = URL(string:"https://fierce-peak-97303.herokuapp.com/api/wifi")!
let task = URLSession.shared.dataTask(with: url) { (data, response, error) in
if error != nil {
print(error)
}else {
if let urlContent = data {
do {
let jsonResult = try JSONSerialization.jsonObject(with: urlContent, options: JSONSerialization.ReadingOptions.mutableContainers)
//print(jsonResult))
for item in(jsonResult as? NSArray)! {
let ssid = (item as? NSDictionary)?["ssid"] as? NSString
//print(ssid)
}
self.tableData = jsonResult as! NSArray
DispatchQueue.main.sync(execute: {
self.table.reloadData()
})
}catch {
print("No Json Result Was Found")
}
}
}
}
task.resume()
For example if I click on one line of the table I want to be able to update password.

Answer 1

I managed to do it like this : all formatted for swift 3
//declare parameter as a dictionary which contains string as key and value combination.
let parameters = ["ssid": newSSID.text!,"password": newPass.text!,"lat": newLat.text!,"lon": newLon.text!,"summary": newSum.text!] as Dictionary<String, String>
//create the url with NSURL
let url = URL(string: "https://fierce-peak-97303.herokuapp.com/api/wifi")
//create the session object
let session = URLSession.shared
//now create the NSMutableRequest object using the url object
let request = NSMutableURLRequest(url: url!)
request.httpMethod = "POST"
var err : NSError?
do {
request.httpBody = try JSONSerialization.data(withJSONObject: parameters, options: [])
}catch{
print("error")
}
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
//create dataTask using the session object to send data to the server
let task = session.dataTask(with: request as URLRequest, completionHandler: {data, response, error -> Void in
print("Response: \(response)")
let strData = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
print("Body: \(strData)")
var err: NSError?
do {
var json = try JSONSerialization.jsonObject(with: data!, options: .mutableLeaves) as? NSDictionary
}catch{
print("JSON error")
}
// Did the JSONObjectWithData constructor return an error? If so, log the error to the console
if(err != nil) {
print(err!.localizedDescription)
let jsonStr = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
print("Error could not parse JSON: '\(jsonStr)'")
}
else {
// The JSONObjectWithData constructor didn't return an error. But, we should still
// check and make sure that json has a value using optional binding.
do {
let json = try JSONSerialization.jsonObject(with: data!, options: .mutableLeaves) as? NSDictionary
if let parseJSON = json {
// Okay, the parsedJSON is here, let's get the value for 'success' out of it
let success = parseJSON["success"] as? Int
print("Success: \(success)")
}
else {
// Woa, okay the json object was nil, something went worng. Maybe the server isn't running?
let jsonStr = NSString(data: data!, encoding: String.Encoding.utf8.rawValue)
print("Error could not parse JSON: \(jsonStr)")
}
}catch{
print("JSON error")
}
}

Answer 2

You can get the contents of the json file as whatever data structure you want, then overwrite the values that you want to change and finally overwrite the original file when you want to save your changes:
So you're already getting the JSON as an array:
let jsonResult = try JSONSerialization.jsonObject(with: urlContent, options: JSONSerialization.ReadingOptions.mutableContainers)
let array = (jsonResult as? NSArray)!
So now you can just change the values in array, when you're done changing everything you want then you can overwrite the json file: (swift 3.0)
var jsonData: NSData!
// serialize json dataa
do
{
jsonData = try JSONSerialization.dataWithJSONObject(array, options: NSJSONWritingOptions())
let jsonString = String(data: jsonData as Data, encoding: String.Encoding.utf8)
print(jsonString)
}
catch let error as NSError
{
print("Array to JSON conversion failed: \(error.localizedDescription)")
}
// overwrite the contents of the original file.
do
{
let file = try FileHandle(forWritingToURL: url!)
file.writeData(jsonData)
print("JSON data was written to the file successfully!")
}
catch let error as NSError
{
print("Couldn't write to file: \(error.localizedDescription)")
}
I'm not sure exactly how writing to a server works, but since it's a URL i think it should act the same way.
Update:
So your original array is:
let array = (jsonResult as? NSArray)!
You can cast it to an array of dictionaries like so
var dictionaries : [[String: NSObject]] = array as? [[String: NSObject]]
and you get ssid by doing:
int i = 0;
for (dictionary in dictionaries)
{
let ssid = dictionary["ssid"]
let newSSID = ssid + "something I want to edit my values with"
// now we have our new value, so we update the array
dictionaries[i]["ssid"] = newSSID
i += 1
}
now after this we just overwrite the original file with the new dictionaries object, which I wrote out above.