How to parse a Socket.IO payload (== packets bunched together), so that we can parse them as individual packets.

gistfile1.m

// Sometimes Socket.IO "batches" up messages in one packet,
// so we have to split them.
// 
- (NSArray *)packetsFromPayload:(NSString *)payload
{
    // "Batched" format is:
    // �[packet_0 length]�[packet_0]�[packet_1 length]�[packet_1]�[packet_n length]�[packet_n]
    
    if([payload hasPrefix:@"\ufffd"]) {
        // Payload has multiple packets, split based on the '�' character
        NSMutableArray *packets = [NSMutableArray arrayWithCapacity:2];
        // Skip the first character, then split
        NSArray *split = [[payload substringFromIndex:1] componentsSeparatedByString:@"\ufffd"];
        // Now all of the odd-numbered indices are the packets (1, 3, 5, etc.)
        for (NSInteger i=0; i<split.count; i++) {
            if (i % 2 != 0) {
                [packets addObject:split[i]];
            }
        }
        NSLog(@"Parsed a payload!");
        return packets;
    } else {
        // Regular single-packet payload
        return @[payload];
    }
}