NSJSONSerialization gives me error "Duplicate key"

Question

I request a JSON response from a home controlling device:

NSData* responseData = [NSData dataWithContentsOfURL:url];

The JSON data in responseData is complete and valid. However, if I try

NSDictionary* dict = [NSJSONSerialization 
                          JSONObjectWithData:responseData                          
                          options:kNilOptions 
                          error:&error];
NSLog("Error: %@", error);

it gives me the following error:

Error: Error Domain=NSCocoaErrorDomain Code=3840 "The operation couldn’t be completed. (Cocoa error 3840.)" (Duplicate key for object around character 0.) UserInfo=0x6a8b8e0 {NSDebugDescription=Duplicate key for object around character 0.}

I searched the web but couldn't find anything helpful so far.

Edit: The JSON response it quite long, so instead of posting it here, please find it here.

It would be easier if you show use the JSON string. – MByD Mar 25 '12 at 09:44 — MByD, Mar 25 '12 at 09:44

score 0 · Answer 1 · answered Jun 13 '12 at 11:19

0

I get the same error, only at random when the app runs. When the NSJSONSerialization fails I've checked the json object it chocks on using a JSON Viewer. The JSON is always OK. Bugs in NSJSONSerialization when it's called several times?

answered Jun 13 '12 at 11:19

Kai Friis

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1
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I've switched to TouchJSON and it did a great job so far. Give it a try! :) – Norbert Jun 13 '12 at 11:35

score 0 · Answer 2 · answered Dec 01 '12 at 06:20

0

I got the same error. My JSON data passed JSON validator at http://jsonformatter.curiousconcept.com/ . However, I found two duplicated keys in my JSON (at the end of dictionary). After I removed those keys, NSJSONSerialization works smoothly.

answered Dec 01 '12 at 06:20

Hai Feng Kao

5,219
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JSON doesn't define how duplicate keys should be handled. Anything putting JSON into NSDictionary cannot possibly handle them in a meaningful way. – gnasher729 Apr 15 '14 at 08:18

score 0 · Accepted Answer · answered Mar 25 '12 at 10:40

0

It looks like the JSON is fine by pasting it into http://jsonformat.com/ - maybe you found an Apple bug? Another way to try and validate would be to use a third-party iOS library and see if it gives you the same error? Say, TouchJSON?

answered Mar 25 '12 at 10:40

Scott Corscadden

2,831
1
25
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Thanks! TouchJSON worked for me, I reported this incident to Apple. – Norbert Mar 25 '12 at 17:08

NSJSONSerialization gives me error "Duplicate key"

3 Answers3

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