how to retrive JSON data by using swift - json

Question

I am retrieving datas from JSON by using swift. I am new to JSON. I don't how to retrieve this nested values. My previous question is Issue raised, while retriving datas from JSON by using swift . I got clarified. This is new to me. My JSON format is below. Kindly guide me.
JSON Response formats:
{
"salutation": {
"id": 1,
"salutation": "Mr"
},
"firstName": "AAA",
"middleName": "BBB",
"lastName": "C",
"employeeId": "RD484",
"station": {
"id": 86,
"stationCode": null,
"stationName": "DDD",
"subDivision": null,
"address": null
},
"subDivsion": {
"id": 11,
"divisionCode": "11",
"divisionDesc": "EEE",
"division": null
}
}
//My Attempt:
var maindict = NSDictionary() //Global declaration
var session = NSURLSession.sharedSession()
//now create the NSMutableRequest object using the url object
let request = NSMutableURLRequest(URL: url!)
request.HTTPMethod = "POST" //set http method as POST
var err: NSError?
request.HTTPBody = NSJSONSerialization.dataWithJSONObject(parameters, options: nil, error: &err) // pass dictionary to nsdata object and set it as request body
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
println("Response: \(response)")
self.maindict = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as [String: AnyObject]
var err: NSError?
var json = NSJSONSerialization.JSONObjectWithData(data, options: .MutableLeaves, error: &err) as? NSDictionary
// Did the JSONObjectWithData constructor return an error? If so, log the error to the console
if(err != nil) {
println(err!.localizedDescription)
let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
//println("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.
if let parseJSON = json {
// Okay, the parsedJSON is here, let's get the value for 'success' out of it
var success = parseJSON["success"] as? Int
println("Succes: \(success)")
self.dataFromJSON() //METHOD CALLING
}
else {
// Woa, okay the json object was nil, something went worng. Maybe the server isn't running?
let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
println("Error could not parse JSON: \(jsonStr)")
//println("AUTHENTICATION FAILED")
}
}
})
task.resume()
func dataFromJSON()
{
println("Main Dict Values: \(maindict)") //PRINTING ALL VALUES
let dataArray = maindict["firstName"] as? [String:AnyObject]
println("FirstName Values: \(dataArray)") // PRINTING NIL VALUES
}

Answer 1

Your data structure does not begin with an array this time, but with a Dictionary. Your structure is like is:
root Dictionary -> "salutation" -> Dictionary
root Dictionary -> "station" -> Dictionary
root Dictionary -> "subDivsion" -> Dictionary
Let's say you want to access the "id" of "salutation", then:
// Just an exemple of how to download, surely you have your own way
func getJSON(url: NSURL) {
let session = NSURLSession.sharedSession()
let request = NSURLRequest(URL: url)
let task = session.dataTaskWithRequest(request){
(data, response, downloadError) -> Void in
if let error = downloadError {
println(error.localizedDescription)
} else {
var jsonError: NSError?
// cast the result as a Dictionary
if let dict = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &jsonError) as? [String: AnyObject] {
// print the dictionary to check contents
println(dict)
if let salutationDictionary = dict["salutation"] as? [String: AnyObject] {
if let id = salutationDictionary["id"] as? Int {
println(id)
}
}
}
if jsonError != nil {
println(jsonError)
}
}
}
task.resume()
}
EDIT:
My friend, your code was a mess... I suggest to you to do some cleaning when you've got errors, it helps to debug. Anyway, here's a corrected version of your new code. Pay attention to how maindict is declared on the first line. Also, you had one unnecessary call to NSJSONSerialization, I simplified it. Note: for the sake of the example, I've included your dataFromJSON function code directly inside if let parseJSON ..., but of course it doesn't mean you have to do the same.
var maindict: [String: AnyObject]?
var session = NSURLSession.sharedSession()
//let parameters = ...
let request = NSMutableURLRequest(URL: your_url!)
request.HTTPMethod = "POST"
var err: NSError?
request.HTTPBody = NSJSONSerialization.dataWithJSONObject(parameters, options: nil, error: &err)
request.addValue("application/json", forHTTPHeaderField: "Content-Type")
request.addValue("application/json", forHTTPHeaderField: "Accept")
var task = session.dataTaskWithRequest(request, completionHandler: {data, response, error -> Void in
println("Response: \(response)")
var err: NSError?
maindict = NSJSONSerialization.JSONObjectWithData(data, options: nil, error: &err) as? [String: AnyObject]
if err != nil {
println(err!.localizedDescription)
} else {
if let parseJSON = maindict {
var success = parseJSON["success"] as? Int
println("Succes: \(success)")
println("Main Dict Values: \(maindict)")
let firstName = maindict!["firstName"] as? String
println("FirstName: \(firstName)")
}
else {
let jsonStr = NSString(data: data, encoding: NSUTF8StringEncoding)
println("Error could not parse JSON: \(jsonStr)")
}
}
})
task.resume()
Please pay attention to the details and study my modifications by comparing with your attempt. My answer has been tested on my own server and it works, so you can use it as a working base.

Answer 2

The easiest way to do this is to use a library.
1) You can use swiftyJSON. It uses the objective C JSON parsing library.
https://github.com/SwiftyJSON/SwiftyJSON
2) If you want a library which uses a pure swift parser try JSONSwift. The readme on github shows how you can retrieve nested values from the JSON file. And integrating it in your project just requires you to import a single file. https://github.com/geekskool/JSONSwift