I have used AsyncUdpSocket successfully to run SSDP Discovery and find controllers. Here are my code snippets:
Initialize and setup the socket:
// AsyncUdpSocket *ssdpSock = [[AsyncUdpSocket alloc] initWithDelegate:self];
AsyncUdpSocket *ssdpSock = [[AsyncUdpSocket alloc] initIPv4];
[ssdpSock setDelegate:self];
Note the first line commented out. I found on the AsyncUdpSocket forums some issues with duplicates. I don't think I was facing them but I did it anyhow.
I added error checking, and it was useful because during my debugging I wasn't closing sockets and I started getting socket setup failures:
NSError *socketError = nil;
if (![ssdpSock bindToPort:1900 error:&socketError]) {
NSLog(@"Failed binding socket: %@", [socketError localizedDescription]);
return statusController;
}
if(![ssdpSock joinMulticastGroup:@"239.255.255.250" error:&socketError]){
NSLog(@"Failed joining multicast group: %@", [socketError localizedDescription]);
return statusController;
}
if (![ssdpSock enableBroadcast:TRUE error:&socketError]){
NSLog(@"Failed enabling broadcast: %@", [socketError localizedDescription]);
return statusController;
}
[ssdpSock sendData:[self.discoverControllerString dataUsingEncoding:NSUTF8StringEncoding]
toHost:@"239.255.255.250"
port:1900
withTimeout:2
tag:1];
Notice the changes I have made to the time out. And then finally did the receive setup, and closed the socket. Note the socket close. Since I am in my own class when I am running this - the code above did not work for me.
[ssdpSock receiveWithTimeout: 2 tag:1];
[NSTimer scheduledTimerWithTimeInterval: 5 target: self
selector:@selector(completeSearch:) userInfo: self repeats: NO];
[ssdpSock closeAfterSendingAndReceiving];
The most important change probably was returning "NO" if I did not find my controller. The first receive was incidentally the discovery message itself coming back. And when I read through the AsyncUdpSocket.h file carefully - returning "NO" when it is not a packet you are looking for helped.
Also note that I am using ARC in my code but I compiled the AsyncUdpSocket without ARC support.
-(void) completeSearch: (NSTimer *)t
{
NSLog(@"%s",__FUNCTION__);
//[ssdpSock close];
//ssdpSock = nil;
}
- (BOOL)onUdpSocket:(AsyncUdpSocket *)sock
didReceiveData:(NSData *)data
withTag:(long)tag
fromHost:(NSString *)host
port:(UInt16)port
{
NSLog(@"%s %ld %@ %d",__FUNCTION__,tag,host,port);
NSString *aStr = [[NSString alloc] initWithData:data encoding:NSASCIIStringEncoding];
NSLog(@"%@",aStr);
NSString *compareString = [aStr stringByPaddingToLength:[self.responseString length] withString:@"." startingAtIndex:0];
//NSLog(@"%@", compareString);
//NSLog(@"%@", self.responseString);
if ([compareString isEqualToString:self.responseString])
{
NSLog(@"String Compare, Controller Found!");
[self.controllerList addObject:aStr];
//NSData *controllerIP = [aStr dataUsingEncoding:NSUTF8StringEncoding];
[[NSNotificationCenter defaultCenter] postNotificationName:@"DiscoveredController" object:nil];
return YES;
}
return NO;
}
