Performing RestKit Mapping Operation Manually

gistfile1.m

id<RKParser> parser = [[RKParserRegistry sharedRegistry] parserForMIMEType:RKMIMETypeJSON];
NSError *error = nil;
id parsedObject = [parser objectFromString:JSON error:&error];
if (parsedObject) {
    NSManagedObject *destinationObject = // init or fetch your target object
    RKObjectMappingOperation *operation = [RKObjectMappingOperation mappingOperationFromObject:parsedObject toObject:destinationObject withMapping:yourObjectMapping];
    BOOL success = [operation performMapping:&error];
}