Three20 JSONP parser

JSONPResponse.h

#import <extThree20JSON/extThree20JSON.h>
#import <extThree20JSON/NSObject+SBJSON.h>

@interface JSONPResponse : TTURLJSONResponse {

}

@end

JSONPResponse.m

#import "JSONPResponse.h"

#import <Three20Core/Three20Core.h>

@implementation JSONPResponse


// This method is based on the same-named method in TTURLJSONResponse
// Note, that only SBJSON suport is left
- (NSError *) request: (TTURLRequest *) request processResponse: (NSHTTPURLResponse *) response
                 data: (id) data {

    // This response is designed for NSData objects, so if we get anything else it's probably a
    // mistake.
    TTDASSERT([data isKindOfClass: [NSData class]]);
    TTDASSERT(nil == _rootObject);
    NSError *err = nil;
    if ([data isKindOfClass: [NSData class]]) {
        NSString *json = [[[NSString alloc] initWithData: data encoding: NSUTF8StringEncoding] autorelease];

        // Remove JSONP wrapper

        json = [json stringByTrimmingCharactersInSet: [NSCharacterSet whitespaceAndNewlineCharacterSet]];
        NSRange openingBracket = [json rangeOfString: @"("];
        NSRange closingBracket = [json rangeOfString: @")" options: NSBackwardsSearch];

        if (openingBracket.location != NSNotFound && closingBracket.location != NSNotFound) {
            json = [json substringWithRange:
                    NSMakeRange(openingBracket.location + 1, closingBracket.location - openingBracket.location - 1)];

            // Parse JSON
            _rootObject = [[json JSONValue] retain];
        }

        // Report error if failed to parse
        if (!_rootObject) {
            err = [NSError errorWithDomain: kTTExtJSONErrorDomain
                                      code: kTTExtJSONErrorCodeInvalidJSON
                                  userInfo: nil];
        }
    }

    return err;
}


@end

Make sure you check my blog post about it – http://www.componentix.com/blog/21