Question

I have a certain json:

[
    {
        "id"        : 42422422,
        "created"   : 1329684013,
        "name"          : "Test"
    },
    {
        "id"        : 42422423,
        "created"   : 1329684015,
        "name"          : "Test 123"
    },
        {
          ...
        }
]

Parsing this goed OK, but when the webserver has an error, this JSON is returned:

{
    "error" : {
        "code"      : "511",
        "message"   : "JSON error",
        "extra" : {
            "some"      : "text",
            "someextra" : "text"
        }
    }
}

I’ve tried using this:

if ([jsonArray valueForKey:@"error"] != nil) {

but that doesn’t work, because if I output the value of that it’s an array of ‘null’s’

How can I check this? (I know I can use NSRange, but I think there has to be a better way right?

I parse the JSON like this:

NSDictionary *jsonArray = [NSJSONSerialization JSONObjectWithData:responseData options:NSJSONReadingMutableContainers error: &e]; 

responseData comes from the connectionDidFinishLoading method of NSURLConnection.

Answer 1

You should check if your result is an array or a dictionary first.

if ([jsonArray isKindOfClass:[NSArray class]]) {
     //process results
} else if ([jsonArray isKindOfClass:[NSDictionary class]]) {
    NSDictionary *errorInfo = [(NSDictionary *)jsonArray objectForKey:@"error"];
    //handle error...
}