Peer Pressure: Adventures in Multipeer Connectivity

This presentation on Multipeer Connectivity was originally given at CocoaConf Raleigh, May 2014.

The Multipeer Connectivity framework included in iOS 7 represents a fundamental shift in how networked apps can be built. Using the Multipeer framework allows developers to tap into a wide range of nearby networking solutions like peer-to-peer Wi-Fi, infrastructure Wi-Fi networks and Bluetooth personal area networks. However, as complicated as this all might sound, don’t worry. The dirty details of all this infrastructure networking have been wrapped up within an API that's relatively compact, easy to understand and quite fun to use!

Transcript

1. Peer Pressure Adventures in Multipeer Connectivity Jay Thrash CocoaConf Raleigh May 2014
2. Multipeer Connectivity Overview
3. Multipeer Connectivity Overview What does it do?
4. “A framework for discovering services provided by, and communicating with, nearby iOS devices” Multipeer Connectivity Overview nearby - WWDC, June 2013
5. Multipeer Connectivity Overview What does it do? No, really…
6. “A framework for creating an ad-hoc network of nearby iOS devices” Multipeer Connectivity Overview - Me, just now
7. Multipeer Connectivity Overview Wi-Fi Bluetooth Peer-to-Peer Wi-Fi R.Y.O.N.N. It’s Magic!
8. “A framework for creating an ad-hoc network of that allows nearby iOS devices to communicate” Multipeer Connectivity Overview - Me, (again), just now
9. Multipeer Connectivity Overview Why does it matter?
10. ✉️ ✉️ ✉️ Multipeer Connectivity Overview ✉️
11. ✉️ ✉️ ✉️ Multipeer Connectivity Overview ✉️ ☁
12. ✉️ ✉️ ✉️ Multipeer Connectivity Overview
13. Multipeer Connectivity Overview MOREEfficient Secure
14. Multipeer Connectivity Lifecycle
15. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
16. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
17. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate ? ?
18. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate ✅ ✅
19. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
20. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
21. Multipeer Connectivity Implement
22. Multipeer Connectivity Implement @import MultipeerConnectivity; Step 0: Import Framework
23. Multipeer Connectivity Implement MCPeerID peerID = [[MCPeerID alloc] initWithDisplayName:peerName]; Step 1: Create Identity
24. Multipeer Connectivity Implement MCSession session = [[MCSession alloc] initWithPeer:peerID]; Step 2: Create Session
25. Multipeer Connectivity Implement MCAdvertiserAssistant advertiser = [[MCAdvertiserAssistant alloc] initWithServiceType:serviceType discoveryInfo:nil session:session]; ! advertiser.delegate = self; [advertiser start]; Step 3: Advertise
26. Multipeer Connectivity Implement MCBrowserViewController browser = [[MCBrowserViewController alloc] initWithServiceType:serviceType session:session]; browser.minimumNumberOfPeers = min; browser.maximumNumberOfPeers = max; browser.delegate = self; [self presentViewController:browser ...]; Step 4: Discover
27. Multipeer Connectivity Implement MCSession Step 5: Communicate Message Stream Resources
28. Multipeer Connectivity Implement MCSession // Send Message [session sendData:messageData toPeers:@[peerID,peerID,peerID,…] withMode:MCSessionSendDataReliable error:&error]; ! // MCSessionSendDataReliable is faster, but… // delivery is not guaranteed // nor is order Step 5: Communicate
29. Multipeer Connectivity Implement MCSessionDelegate // Receive Message -(void) session:(MCSession *)session didReceiveData:(NSData *)data fromPeer:(MCPeerID *)peerID { // Unarchive data to object ! } ! Step 5: Communicate
30. Multipeer Connectivity Implement MCSession // Create Stream NSOutputStream *stream = [session startStreamWithName:streamName toPeer:peerID error:&error] // write to stream ! Step 5: Communicate
31. Multipeer Connectivity Implement MCSessionDelegate // Receive on stream - (void)session:(MCSession *)session didReceiveStream:(NSInputStream *)stream withName:(NSString *)name fromPeer:(MCPeerID *)peerID ! Step 5: Communicate
32. Multipeer Connectivity Implement MCSession // Send resource NSProgress *progress = [session sendResourceAtURL:url withName:name toPeer:peerID completionHandler:completionHandler]; ! // controlling transfer progress.fractionCompleted; [progress cancel]; Step 5: Communicate
33. Multipeer Connectivity Implement MCSessionDelegate // Receiving Resource - (void)session:(MCSession *)session didStartReceivingResourceWithName:(NSString *) resourceName:(NSString *) fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *) prg ! Step 5: Communicate
34. Multipeer Connectivity Implement MCSessionDelegate // Received Resource (void)session:(MCSession *) sessiondidFinishReceivingResourceWithName:(NSString*) resourceName fromPeer:(MCPeerID *)peerID atURL:(NSURL *)localURL withError:(NSError *)error { // completed transfer } Step 5: Communicate
35. Multipeer Connectivity Implement MCSession ! // Leave Session [session disconnect]; Step 5: Connection Status
36. Multipeer Connectivity Implement MCSessionDelegate // Someone left the session ! -(void) session:(MCSession *) peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state; { // MCSessionStateNotConnected // MCSessionStateConnecting // MCSessionStateConnected } Step 5: Connection Status
37. Multipeer Connectivity Implement MCSession // handle changes on the main thread ! dispatch_async(dispatch_get_main_queue(), ^{ [self doThingWithData]; }); Step 5: Communicate !
38. Multipeer Connectivity D V M emo inimum iable
39. Multipeer Connectivity Demo
40. Multipeer Connectivity Demo Bob Mary Bob Mary Jay
41. Multipeer Connectivity Demo Bob Mary Bob Mary Jay
42. Multipeer Connectivity Demo Bob Mary Jay
43. Multipeer Connectivity Demo Bob Mary Jay
44. Multipeer Connectivity Demo Bob Mary Jay
45. Multipeer Connectivity Demo
46. Extra Credit Some things we didn’t cover •Programmatic advertising, discovery and session joining (app specific) •Streaming data •Sending resources !
47. Higher Learning Topics to Google •NSHipster •WWDC 2013 (Talk 708) •Objc.io (drones!!) •Apple Docs (MP Framework)
48. Thanks! @jaythrash jay@jaythrash.com http://jaythrash.com/talks