SBJSON parsing issue with Twitter's GET trends/:woeid - objective-c

Question

I am trying to understand an issue I am having when using sbjson to parse the following json returned by a call to Twitter's GET trends/:woeid
I am using the following URL: #"http://api.twitter.com/1/trends/1.json" and I get the following response: (truncated to save space)
[
{
"trends": [
{
"name": "Premios Juventud",
"url": "http://search.twitter.com/search?q=Premios+Juventud",
"query": "Premios+Juventud"
},
{
"name": "#agoodrelationship",
"url": "http://search.twitter.com/search?q=%23agoodrelationship",
"query": "%23agoodrelationship"
}
],
"as_of": "2010-07-15T22:40:45Z",
"locations": [
{
"name": "Worldwide",
"woeid": 1
}
]
}
]
Here is the code I'm using to parse and display the name and url:
NSMutableString *content = [[NSMutableString alloc] initWithBytes:[responseData bytes] length:[responseData length] encoding:NSUTF8StringEncoding];
[content replaceCharactersInRange:NSMakeRange(0, 1) withString:#""];
[content replaceCharactersInRange:NSMakeRange([content length]-1, 1) withString:#""];
NSLog(#"Content is: %#", content);
SBJsonParser *parser = [[SBJsonParser alloc] init];
NSDictionary *json = [parser objectWithString:content];
//NSArray *trends = [json objectForKey:#"trends"];
NSArray *trends = [json objectForKey:#"trends"];
for (NSDictionary *trend in trends)
{
[viewController.names addObject:[trend objectForKey:#"name"]];
[viewController.urls addObject:[trend objectForKey:#"url"]];
}
[parser release];
This is sample code that is broken because it was targeted to Twitter's GET trends call which is now deprecated. The code will only work if I manually remove the first '[' and last ']'. However if I don't remove those characters from the response, the parser returns a NSArray of one NSString element: the json response.
How should I correctly parse this response. Thanks in advance.

Answer 1

I worked the issue out myself, I was confused by the NSArray coming back with only one element that appeared to be a string.
The one element in the array was not an NSString but a NSDictionary, once I understood this I could approach the data correctly by assigning the element to a NSDictionary, then accessing the "trends' data with the appropriate key:
NSMutableString *content = [[NSMutableString alloc] initWithBytes:[responseData bytes] length:[responseData length] encoding:NSUTF8StringEncoding];
SBJsonParser *parser = [[SBJsonParser alloc] init];
NSArray *json = [parser objectWithString:content];
NSDictionary *trends = [json objectAtIndex:0];
for (NSDictionary *trend in [trends objectForKey:#"trends"])
{
[viewController.names addObject:[trend objectForKey:#"name"]];
[viewController.urls addObject:[trend objectForKey:#"url"]];
}
[parser release];
It's a bit cleaner using the newly released NSJSONSerialization provided by Apple:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSArray *json = [NSJSONSerialization JSONObjectWithData:responseData options:0 error:nil];
NSDictionary *trends = [json objectAtIndex:0];
for (NSDictionary *trend in [trends objectForKey:#"trends"])
{
[viewController.names addObject:[trend objectForKey:#"name"]];
[viewController.urls addObject:[trend objectForKey:#"url"]];
}
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[viewController.serviceView reloadData];
}