Error with parsing JSON with NSJSONSerialization - objective-c

Question

I use openweathermap API to print current weather. I need to parse this JSON (JSON with available cities). I tried to parse it with NSJSONSerializer, but the answer was :"error NSError * domain: #"NSCocoaErrorDomain" - code: 3840".
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"city.list" ofType:#"json"];
NSString *myJSON = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
NSError *error;
NSData *objectData = [myJSON dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:objectData options:NSJSONReadingMutableContainers error:&error];
As i understand, error 3840 says about wrong JSON format, but i have downloaded JSON from official openweathermap page. What's wrong? How parse this JSON correctly?

Answer 1

The file is no valid JSON, but a list of valid JSONs.
{"_id":707860,"name":"Hurzuf","country":"UA","coord":{"lon":34.283333,"lat":44.549999}}
{"_id":519188,"name":"Novinki","country":"RU","coord":{"lon":37.666668,"lat":55.683334}}
{"_id":1283378,"name":"Gorkhā","country":"NP","coord":{"lon":84.633331,"lat":28}}
…
Such a list in a valid JSON would look like this …:
[
{"_id":707860,"name":"Hurzuf","country":"UA","coord":{"lon":34.283333,"lat":44.549999}},
{"_id":519188,"name":"Novinki","country":"RU","coord":{"lon":37.666668,"lat":55.683334}},
{"_id":1283378,"name":"Gorkhā","country":"NP","coord":{"lon":84.633331,"lat":28}},
…
]
… or like this …
{
{"707860": {"name":"Hurzuf","country":"UA","coord":{"lon":34.283333,"lat":44.549999}},
{"519188": {"name":"Novinki","country":"RU","coord":{"lon":37.666668,"lat":55.683334}},
{"1283378":{"name":"Gorkhā","country":"NP","coord":{"lon":84.633331,"lat":28}},
…
However, what you can do is to iterate over the list and convert it item separately:
NSString *filePath = [[NSBundle mainBundle] pathForResource:#"city.list" ofType:#"json"];
NSString *myList = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
// Separate the lines
NSArray *myItems = [myList componentsSeperatedByCharactersInSet:[NSCharacterSet newLineCharacterSet];
NSError *error;
for( NSString *JSON in myItems )
{
if( [JSON length]==0)
{
// empty line
continue;
}
NSData *objectData = [JSON dataUsingEncoding:NSUTF8StringEncoding];
NSDictionary *object = [NSJSONSerialization JSONObjectWithData:objectData options:NSJSONReadingMutableContainers error:&error];
if( object == nil )
{
NSLog( #"Error %# reading\n%#", error, JSON);
}
}

Answer 2

Your json is not formatted correctly.
{"_id":707860,"name":"Hurzuf","country":"UA","coord":{"lon":34.283333,"lat":44.549999}}
{"_id":519188,"name":"Novinki","country":"RU","coord":{"lon":37.666668,"lat":55.683334}}
should be
[{"_id":707860,"name":"Hurzuf","country":"UA","coord":{"lon":34.283333,"lat":44.549999}},
{"_id":519188,"name":"Novinki","country":"RU","coord":{"lon":37.666668,"lat":55.683334}},
...]
Note the encapsulating square brackets and commas at the end.
Or you could parse the text line-by-line (it seems it is ment to be parsed like that).