How can I use NSJSONSerialization with special characters like "ñ"? - ios

Question

I'm using NSJSONSerialization to parse Google suggestions.
The query "f" returns these suggestions:
["f",["facebook","flipkart","fox news","forever 21","friv","fandango","fedex","fitbit","food near me","flights"]]
The parser works fine but when there are special characters like "ñ" for the query "fac":
["fac",["facebook","facebook search","fac","facebook app","facebook lite","facebook login","facebook logo","facebook messenger","facetime","facebook en español"]]
It throws an exception:
Error Domain=NSCocoaErrorDomain Code=3840 "Unable to convert data to string around character 139." UserInfo={NSDebugDescription=Unable to convert data to string around character 139.}
Any ideas? I tried all different reading options but none of them works.
#pragma mark -
- (void)request:(NSString *)text
{
NSMutableArray *items = [[NSMutableArray alloc] init];
NSString *query = [text stringByAddingPercentEncodingWithAllowedCharacters:[NSCharacterSet URLQueryAllowedCharacterSet]];
NSString *languageCode = [[NSLocale preferredLanguages] firstObject];
if (!languageCode) {
languageCode = #"en";
}
NSString *URLString = [NSString stringWithFormat:#"http://suggestqueries.google.com/complete/search?q=%#&client=firefox&hl=%#", query, languageCode];
NSError *downloadError = nil;
NSData *JSONData = [NSData dataWithContentsOfURL:[NSURL URLWithString:URLString] options:0 error:&downloadError];
if (!downloadError && JSONData) {
NSError *parseError = nil;
id object = [NSJSONSerialization JSONObjectWithData:JSONData options:NSJSONReadingMutableContainers error:&parseError];
if (!parseError && object) {
if ([object isKindOfClass:[NSArray class]]) {
NSArray *objects = (NSArray *)object;
NSArray *texts = [objects objectAtIndex:1];
for (NSString *text in texts) {
SNGoogleItem *item = [[SNGoogleItem alloc] initWithText:text];
[items addObject:item];
}
[_delegate google:self didRespondWithItems:items];
}
else {
[_delegate google:self didRespondWithItems:items];
}
}
else {
[_delegate google:self didRespondWithItems:items];
}
}
else {
[_delegate google:self didRespondWithItems:items];
}
}

Answer 1

JSONSerialization supports all the encodings in JSON spec, says Apple documentation.
You didn't provide much info about the encoding scheme of your data but I guess you use nonLossyASCII or something like that, which is not supported by JSONSerialization.
Here is how I convert data to/from JSON:
let rawString = "[[\"facebook en español\"]]"
// if I use String.Encoding.nonLossyASCII below, I get the error you are getting
let data = rawString.data(using: String.Encoding.utf8)
let dict = try! JSONSerialization.jsonObject(with: data!)
let convertedData = try! JSONSerialization.data(withJSONObject: dict)
let convertedString = String(data: convertedData, encoding: String.Encoding.utf8)!
// now convertedString contains "ñ" character

Answer 2

This will convert whatever encoding used to UTF8:
NSData *JSONData = [NSData dataWithContentsOfURL:[NSURL URLWithString:URLString] options:0 error:&downloadError];
NSString *convertedJSONString; BOOL usedLossyConversion;
[NSString stringEncodingForData:JSONData encodingOptions:0 convertedString:&convertedJSONString usedLossyConversion:&usedLossyConversion];
NSData *convertedJSONData = [convertedJSONString dataUsingEncoding:NSUTF8StringEncoding];
Now, it works!