JSON Serialization in Swift iOS

Question

How can I serialize JSON in swift? I am trying to serialize using this method, however it is causing EXC_BAD_INSTRUCTION. For downloading JSON data, I am using NSURLConnection.

var sJson : NSDictionary = NSJSONSerialization.JSONObjectWithData(nsMutData, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary

How can I solve it?

Regards

Do you mean deserialisation of the data? JSONObjectWithData will turn your NSMutableData object into an NSDictionary or NSArray, so that's a deserialisation process. Your code fragment looks valid as well - it worked for me. — rickerbh
– rickerbh, Commented Jun 8, 2014 at 13:04
Try catching the error: var error: NSError?' then pass in &error` as the last parameter to JSONObjectWithData — Bill
– Bill, Commented Jun 8, 2014 at 13:15
@rickerbh my server returns me this data: [{"0":"Saleem Anwar","FullName":"Saleem Anwar","1":"DHQ:Hospital, ","PlaceOfCurrentPosting":"DHQ:Hospital, ","2":"Dental Surgeon","Nomenclature":"Dental Surgeon","distance":58.415098441417,"lat_dest":"34.1905283","long_dest":"78.0457054"},{"0":"Sartaj Ali Shah","FullName":"Sartaj Ali Shah","1":"DHQ:Hospital, Swabi","PlaceOfCurrentPosting":"DHQ:Hospital, Swabi","2":"Dental Surgeon","Nomenclature":"Dental Surgeon","distance":105.26937892754,"lat_dest":"34.1236046","long_dest":"78.4718982"}] — user2498079
– user2498079, Commented Jun 8, 2014 at 13:35

Jean Le Moignan · Accepted Answer · 2014-06-08 14:37:10Z

12

Your root-level data is an array of dictionaries -- not a dictionary; therefore replace your line with:

var sJson = NSJSONSerialization.JSONObjectWithData(nsMutData, options: .MutableContainers, error: nil) as NSArray

I tested it and it now works with your data.

Here's how I tested it after having created a "json.txt" file in my project:

var filePath  = NSBundle.mainBundle().pathForResource("json", ofType:"txt")
var nsMutData = NSData(contentsOfFile:filePath)
var sJson     = NSJSONSerialization.JSONObjectWithData(nsMutData, options: .MutableContainers, error: nil) as NSArray

edited Jun 8, 2014 at 14:37

answered Jun 8, 2014 at 14:25

Jean Le Moignan

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1 Comment

user2498079 Over a year ago

Awesome man. I couldn't find such an obvious error. You Sir are genius

Mohammad Sadiq · Accepted Answer · 2016-02-20 13:57:31Z

3

This is the swift 2.0 way

    let path : String = NSBundle.mainBundle().pathForResource("jsonDict", ofType: "JSON")!;
        let data : NSData = NSData(contentsOfFile: path)!;
        var jsonDictionary : NSDictionary
        do {
             jsonDictionary = try NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions()) as! NSDictionary
        } catch {
            print(error)
        }

edited Feb 20, 2016 at 13:57

answered Feb 20, 2016 at 13:45

Mohammad Sadiq

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Comments

Josh Withee · Accepted Answer · 2019-09-20 12:35:01Z

0

In Swift 4+, JSON Serialization is best done by utilizing the Decodable and Encodable protocols.

Apple docs about encoding/decoding (or serializing/deserializing) custom types
Download sample code from Apple on this page

There is also a detailed tutorial by Ray Wenderlich: Encoding and Decoding in Swift

edited Sep 20, 2019 at 12:35

answered Jul 17, 2019 at 16:38

Josh Withee

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1 Comment

user5683940 Over a year ago

You sure about that ?

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