NSDictionary with json

gistfile1.m

@interface NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:
  (NSString*)urlAddress;
-(NSData*)toJSON;
@end
 
@implementation NSDictionary(JSONCategories)
+(NSDictionary*)dictionaryWithContentsOfJSONURLString:
  (NSString*)urlAddress
{
    NSData* data = [NSData dataWithContentsOfURL:
      [NSURL URLWithString: urlAddress] ];
    __autoreleasing NSError* error = nil;
    id result = [NSJSONSerialization JSONObjectWithData:data 
      options:kNilOptions error:&error];
    if (error != nil) return nil;
    return result;
}
 
-(NSData*)toJSON
{
    NSError* error = nil;
    id result = [NSJSONSerialization dataWithJSONObject:self 
      options:kNilOptions error:&error];
    if (error != nil) return nil;
    return result;    
}
@end