Downloading and parsing json in swift

I'm trying to get the JSON from a website and parse it before putting it inside of an iOS view.

Here's my code;

func startConnection(){
        let urlPath: String = "http://binaenaleyh.net/dusor/"
        var url: NSURL = NSURL(string: urlPath)
        var request: NSURLRequest = NSURLRequest(URL: url)
        var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)
        connection.start()
    }

    func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
        self.data.appendData(data)
    }

    func buttonAction(sender: UIButton!){
        startConnection()
    }

    func connectionDidFinishLoading(connection: NSURLConnection!) {
        var err: NSError
        // throwing an error on the line below (can't figure out where the error message is)
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
    }

And this is the link for the JSON;

http://binaenaleyh.net/dusor/

What am I doing wrong here?

Solution 1:

These two functions worked for me:

    func getJSON(urlToRequest: String) -> NSData{
        return NSData(contentsOfURL: NSURL(string: urlToRequest))
    }

    func parseJSON(inputData: NSData) -> NSDictionary{
        var error: NSError?
        var boardsDictionary: NSDictionary = NSJSONSerialization.JSONObjectWithData(inputData, options: NSJSONReadingOptions.MutableContainers, error: &error) as NSDictionary

        return boardsDictionary
    }

Solution 2:

UPDATE: Swift 4

// Asynchronous Http call to your api url, using URLSession:
URLSession.shared.dataTask(with: URL(string: "http://api.site.com/json")!) { (data, response, error) -> Void in
    // Check if data was received successfully
    if error == nil && data != nil {
        do {
            // Convert to dictionary where keys are of type String, and values are of any type
            let json = try JSONSerialization.jsonObject(with: data!, options: .mutableContainers) as! [String: Any]
            // Access specific key with value of type String
            let str = json["key"] as! String
        } catch {
            // Something went wrong
        }
    }
}.resume()

Here is how to do it with Swift 2 and NSURLSession:

// Asynchronous Http call to your api url, using NSURLSession:
NSURLSession.sharedSession().dataTaskWithURL(NSURL(string: "http://api.site.com/json")!, completionHandler: { (data, response, error) -> Void in
    // Check if data was received successfully
    if error == nil && data != nil {
        do {
            // Convert NSData to Dictionary where keys are of type String, and values are of any type
            let json = try NSJSONSerialization.JSONObjectWithData(data!, options: NSJSONReadingOptions.MutableContainers) as! [String:AnyObject]
            // Access specific key with value of type String
            let str = json["key"] as! String
        } catch {
            // Something went wrong
        }
    }
}).resume()

Solution 3:

This code works fine for me. Just init data property with data = NSMutableData() and write NSURLConnectionDelegate here class ViewController: UIViewController, NSURLConnectionDelegate

import UIKit

class ViewController: UIViewController, NSURLConnectionDelegate {

    @lazy var data = NSMutableData()

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        startConnection()
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func startConnection(){
        let urlPath: String = "http://binaenaleyh.net/dusor/"
        var url: NSURL = NSURL(string: urlPath)
        var request: NSURLRequest = NSURLRequest(URL: url)
        var connection: NSURLConnection = NSURLConnection(request: request, delegate: self, startImmediately: false)
        connection.start()
    }

    func connection(connection: NSURLConnection!, didReceiveData data: NSData!){
        self.data.appendData(data)
    }

    func buttonAction(sender: UIButton!){
        startConnection()
    }

    func connectionDidFinishLoading(connection: NSURLConnection!) {
        var err: NSError
        // throwing an error on the line below (can't figure out where the error message is)
        var jsonResult: NSDictionary = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
        println(jsonResult)
    }
}

here is output:

{
    "ders sayisi" = 15;
    dersler =     (
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 2;
            3 = "CEE 102";
            4 = "Logic Circuits";
            5 = 3;
            6 = "6.00";
            7 = "YRD.DO\U00c7.DR.INDRIT MYDERRIZI";
            8 = 0;
            9 = IA;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 2;
            3 = "CIP 102";
            4 = "Civic Involment Projects";
            5 = 0;
            6 = "2.00";
            7 = "SE\U00c7\U0130L AVCI/BA\U015eAK CANSU AK\U00c7EL\U0130K/\U00c7A\U011eLA UNGUN";
            8 = 0;
            9 = P;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 2;
            3 = "COME 108";
            4 = "Algorithms and Programming II";
            5 = 3;
            6 = "6.00";
            7 = "\U00d6\U011eR.G\U00d6R.DR.B\U0130RSEN G\U00dcLDEN \U00d6ZDEM\U0130R";
            8 = 41;
            9 = C;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 2;
            3 = "COME 335";
            4 = "Mobile Application Development";
            5 = 3;
            6 = "5.00";
            7 = "\U00d6\U011eR.G\U00d6R.OZAN UYSAL";
            8 = TeacherHold;
            9 = TeacherHold;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 2;
            3 = "ENG 112";
            4 = "Advanced English For Engineering and Natural Sciences I";
            5 = 2;
            6 = "3.00";
            7 = "OKT.ERIC BEECHER";
            8 = 48;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 2;
            3 = "PHYS 102";
            4 = "Physics II";
            5 = 4;
            6 = "5.00";
            7 = "YRD.DO\U00c7.DR.\U00d6ZG\U00dcL KURTULU\U015e \U00d6ZT\U00dcRK";
            8 = "-1";
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = BAHAR;
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 2;
            3 = "T\U00dcRK 102";
            4 = "T\U00fcrk Dili II";
            5 = 2;
            6 = "2.00";
            7 = "\U00d6\U011eR.G\U00d6R.\U015eER\U0130FE GEZG\U0130N";
            8 = 10;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 1;
            3 = "CHEM 101";
            4 = Chemistry;
            5 = 3;
            6 = "5.00";
            7 = "YRD.DO\U00c7.DR.AY\U015eEN TULPAR";
            8 = TeacherHold;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 1;
            3 = "CIP 101";
            4 = "Civic Involment Projects";
            5 = 0;
            6 = "1.00";
            7 = "YRD.DO\U00c7.DR.FATMA G\U00dcL AYGEN/Staff CIP1/SE\U00c7\U0130L AVCI/D\U0130LAYDA EM\U0130R/BA\U015eAK CANSU AK\U00c7EL\U0130K/\U00c7A\U011eLA UNGUN";
            8 = TeacherHold;
            9 = P;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 3;
            12 = "";
            2 = 1;
            3 = "COME 107";
            4 = "Algorithms and Programming I";
            5 = 4;
            6 = "5.00";
            7 = "PROF.DR.M\U0130TAT UYSAL";
            8 = TeacherHold;
            9 = "C+";
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 1;
            3 = "ENG 101";
            4 = "Advanced English";
            5 = 2;
            6 = "3.00";
            7 = "OKT.EZG\U0130 ARGUN";
            8 = TeacherHold;
            9 = B;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 1;
            12 = "";
            2 = 1;
            3 = "IUL 100";
            4 = "Introduction to University Life";
            5 = 0;
            6 = "1.00";
            7 = "YRD.DO\U00c7.DR.FATMA G\U00dcL AYGEN";
            8 = TeacherHold;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 2;
            12 = "";
            2 = 1;
            3 = "MATH 111";
            4 = "Calculus I";
            5 = 4;
            6 = "5.00";
            7 = "DO\U00c7.DR.G\U00dcRSEL YE\U015e\U0130LOT";
            8 = TeacherHold;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 4;
            12 = "";
            2 = 1;
            3 = "PHYS 101";
            4 = "Physics I [CNE]";
            5 = 4;
            6 = "5.00";
            7 = "YRD.DO\U00c7.DR.AR\U0130F \U00d6ZBAY";
            8 = TeacherHold;
            9 = F;
        },
                {
            0 = "2013-2014";
            1 = "G\U00dcZ";
            10 = TeacherHold;
            11 = 9;
            12 = "";
            2 = 1;
            3 = "T\U00dcRK 101";
            4 = "T\U00fcrk Dili I [CNE]";
            5 = 2;
            6 = "2.00";
            7 = "\U00d6\U011eR.G\U00d6R.ARZU AYG\U00dcN";
            8 = TeacherHold;
            9 = F;
        }
    );
}

Solution 4:

If the original JSON is an array, try this.

func parseJSON(inputData: NSData) -> Array<NSDictionary>{
    var error: NSError?
    var boardsDictionary = NSJSONSerialization.JSONObjectWithData(inputData, options: NSJSONReadingOptions.MutableContainers, error: &error) as Array<NSDictionary>

    return boardsDictionary
}

Solution 5:

The example below sends a request to fetch stock information - it's a bit more comprehensive, but has more cleanup and structure:

import Foundation

private let kSNStockInfoFetchRequestPath:String = "http://dev.markitondemand.com/Api/v2/Quote/json"

private func SNStockInfoFetchRequestURL(symbol:String) -> NSURL? {
  if let components:NSURLComponents = NSURLComponents(string:kSNStockInfoFetchRequestPath) {
    components.queryItems = [NSURLQueryItem(name:"symbol", value:symbol)]
    return components.URL
  }
  return nil
}

private func SNStockInfoFetchRequestURLRequest(symbol:String) ->  NSURLRequest? {
  if let requestURL:NSURL = SNStockInfoFetchRequestURL(symbol) {
    var request:NSMutableURLRequest = NSMutableURLRequest(URL:requestURL)
    request.HTTPMethod = "GET"
    return request
  }
  return nil
}

private func SNStockInfoFetchRequestParseData(receivedData:NSData, error:NSErrorPointer) -> NSDictionary? {
  return NSJSONSerialization.JSONObjectWithData(receivedData, options:NSJSONReadingOptions.MutableContainers, error:error) as? NSDictionary
}

class SNStockInfoFetchRequest: NSObject,
NSURLConnectionDataDelegate
{
  private let symbol:String
  private (set) var fetching:Bool
  private lazy var receivedData = NSMutableData()

  init(symbol:String) {
    self.symbol = symbol
    self.fetching = false
  }

  func start() {
    assert(!fetching, "Should not start a request that has already started!")
    fetching = true
    if let request:NSURLRequest = SNStockInfoFetchRequestURLRequest(symbol) {
      var connection:NSURLConnection = NSURLConnection(request:request, delegate:self, startImmediately:true)!
      connection.start()
    }
  }

  // MARK: NSURLConnectionDataDelegate

  func connection(connection:NSURLConnection, didReceiveData data:NSData) {
    assert(fetching, "Should only receive data while activly fetching!")
    self.receivedData.appendData(data)
  }

  func connectionDidFinishLoading(connection:NSURLConnection) {
    var error:NSError?
    if let result:NSDictionary = SNStockInfoFetchRequestParseData(receivedData, &error) {
      println(result)
    } else {
      println(error)
    }

  }
}

We can now use the request as such:

let fetcher:SNStockInfoFetchRequest = SNStockInfoFetchRequest(symbol:"MSFT")
fetcher.start()

This should output the JSON in case of a success, or the error in case of a failure. Hope this helps! If you use the same structure, make sure to use a delegate to either return the parsed JSON (or even better, an immutable value object) or indicate a failure.