Parsing error with NSJSONSerialization - json

Question

I am facing error while trying to parse JSON from a URL.
Following is the code:
override func viewDidLoad() {
super.viewDidLoad()
print("hello")
let url=NSURL(string:"http://jsonReports/sample_testkrtk252.json")
print("hello2")
if let allContactsData=NSData(contentsOfURL:url!)
{
print(allContactsData)
do{
let allContacts: AnyObject! = try NSJSONSerialization.JSONObjectWithData(allContactsData, options: NSJSONReadingOptions.MutableContainers)
print(allContacts)
if let json = allContacts as? Array<AnyObject> {
print(json)
for index in 0...json.count-1 {
let data12 : AnyObject? = json[index]
print(data12)
let collection = data12! as! Dictionary<String, AnyObject>
print(collection)
print(collection["data11"])
let data11 : AnyObject? = collection["data11"]
let cont : AnyObject? = collection["cont"]
data1.append(data11 as! String)
data2.append(cont as! String)
print(data1)
print(data2)
}
}
}
catch
{
print("error")
}
}
And after the successful run it gives the following output:
hello
hello2
<7b0d0a20 20202022 ... >
error
(lldb)
Also, it gives the error:
NSError Domain: "NSCocoaErrorDomain" - code: 3840 0x00007f8b62c9ef50 _userInfo __NSDictionaryI * 1 key/value pair 0x00007f8b62dcb3c0
It will be great if someone can look into this. Also, is there any better way to parse JSON in Swift?

Answer 1

your file .json is not a valid structure. Delete the first line:
"registration_id":APA91bEVsOgzkFFDCuEFn8PAS-FQqeaW6TRuz09CeKSnAJUSJmTvP8ubIsUkUe2zOzz8vk-FNqbNteOcD6m8m5nhrNWA96swZHYyX4nvY-mPCJTeBkEXTLuLwWCglbAUVCqJlwharLLJ,
Now try to run the code:
func run()->(Void){
//insert you file .jso into project. Or change the code
let filePath = NSBundle.mainBundle().pathForResource("sample_testkrtk252", ofType:"json")
let nsMutData:NSData = NSData(contentsOfFile:filePath!)!
do{
let allContacts:[String:AnyObject] = try NSJSONSerialization.JSONObjectWithData(nsMutData, options: NSJSONReadingOptions.MutableContainers) as! [String : AnyObject]
print(allContacts)
for temp in 0...allContacts.count-1 {
print(temp)
}
} catch
{
print("error")
}
}

Answer 2

Why not directly casting the AnyObject returned JSONObjectWithData to an array of NSDictionary? Like this:
let allContacts = try NSJSONSerialization.JSONObjectWithData(allContactsData, options: NSJSONReadingOptions.MutableContainers) as! [NSDictionary]
Are you sure your JSON is valid? Swift is very sensitive about that. Make sure all keys are quoted and you didn't forget any braces (especially the most outer ones).
Also for JSON parsing I would recommend SwiftyJSON which makes things a lot easier.

Answer 3

Thanks for your answers.
just editing the json worked for me.
yes, it is true that one needs to follow the format correctly, otherwise a simple double quote can disrupt the expected output. :)
"registration_id":"APA91bEVsOgzkFFDCuEFn8PAS-FQqeaW6TRuz09CeKSnAJUSJmTvP8ubIsUkUe2zOzz8vk-FNqbNteOcD6m8m5nhrNWA96swZHYyX4nvY-mPCJTeBkEXTLuLwWCglbAUVCqJlwharLLJ",
Thanks,
Poulami