Question

I’m using the SBJSON parser to parse a JSON response:

{"status":0,"sessions":[{"name":"kldlksdklsdkl","active":false,"status":"saved","type":"web","key":"30228ee71f09b93aaa2d1738","contributor_id":"lance","created_at":"Mon May 02, 2011 02:35 PM","closed_at":"Mon May 02, 2011 02:46 PM"}{"name":"Blahieririe","active":false,"status":"saved","type":"web","key":"dbd2bbcc8681bba6a6532051","contributor_id":"lance","created_at":"Mon May 02, 2011 01:42 PM","closed_at":"Mon May 02, 2011 02:34 PM"},{"name":"Jim","active":false,"status":"saved","type":"web","key":"ec5bcf18356a29bb4490841f","contributor_id":"lance","created_at":"Fri April 29, 2011 02:37 PM","closed_at":"Fri April 29, 2011 02:38 PM"}]}

from a server using this code:

NSArray *sessionsArray = [dictionary objectForKey:@"sessions"];
    NSArray *tempArray = [[NSArray alloc] init];
    for(NSString *item in sessionsArray){
        NSLog(@"Session Found: \'%@\'",item);

        NSDictionary *myDictionary = [item JSONValue];
    }

I’m getting a nice array from my JSON but when I try to put each piece into an NSDictionary, it gives me an exception and I NSLoged it and discovered that the quotation marks are being removed from some of the keys and or values as seen here:

{
active = 1;
"contributor_id" = lance;
"created_at" = "Mon May 02, 2011 03:26 PM";
key = e10e5feeea3425ae213cb4cc;
name = "JSON TEST";
status = active;
type = web;
}

is it a bug in the JSON parser? or am I doing something stupid?

Answer 1

The quotation marks aren’t ‘being removed’.

In JSON, every string is quoted but the quotes themselves are not part of the strings. For instance, if you write

NSArray *sessionsArray = [dictionary objectForKey:@"sessions"];
NSDictionary *session = [sessionArray objectAtIndex:0];
NSString sessionName = [session objectForKey:@"name"];

the corresponding session name won’t show up with quotation marks.

When you NSLog() a dictionary or an array, Cocoa uses the NeXTSTEP property list format to represent the dictionary/array. In this format, quotes are optional if the values are simple words.

That said, you should enumerate those JSON data as follows:

NSString *jsonString = …;
NSDictionary *jsonResult = [jsonString JSONValue];
NSArray *sessionsArray = [jsonResult objectForKey:@"sessions"];
for (NSDictionary *session in sessionArray) {
    NSString *sessionName = [session objectForKey:@"name"];
    BOOL sessionActive = [[session objectForKey:@"active"] boolValue];
    NSString *sessionStatus = [session objectForKey:@"status"];
    …
}