How does NSJSONSerializer determine the encoding of the given data?

Question

I'm using NSJSONSerializer to parse some json formatted data. The data contains some 'ü' and 'ö' and such. I find that it does return nil, when not beforehand converting the NSData to a NSString with NSASCIIStringEncoding and reconverting it back to NSData, so that 'ü' is converted to u and so on. The original format of the Data is ISO-8859-1. How ca i possibly advise the json parser to use this encoding?

Answer 1

Per RFC 7159:

8.1. Character Encoding

JSON text SHALL be encoded in UTF-8, UTF-16, or UTF-32.

So if your data is encoded in ISO-8859-1 then it is not valid JSON.

Use NSString to convert it to one of the defined acceptable JSON forms:

NSString *string = [[NSString alloc] initWithData:dat encoding:NSISOLatin1StringEncoding];
NSData *utf8Data = [string dataUsingEncoding:NSUTF8StringEncoding];

// ... give utf8Data to NSJSONSerializer