Adventures in Multipeer Connectivity

Originally presented in Greenville, SC at 360|iDev min on 2014-10-07.

The Multipeer Connectivity framework included in iOS 7 represents a fundamental shift in how networked apps can be built. This woefully underused framework allows developers to create efficient and secure peer-to-peer networks that leverage the Wi-Fi and Bluetooth personal area network capabilities contained in all modern iOS devices. 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. in Multipeer Connectivity Jay Thrash [360|iDev min] October 2014 Adventures Adventures
2. Overview Lifecycle Implement Demo
3. Multipeer Connectivity Overview
4. Multipeer Connectivity Overview What does it do?
5. “A framework for discovering services provided by, and communicating with, nearby iOS devices” Multipeer Connectivity Overview - WWDC, June 2013
6. “A framework for discovering services provided by, and communicating with, nearby iOS and OS X devices” Multipeer Connectivity Overview - WWDC, June 2014
7. Multipeer Connectivity Overview What does it do? No, really…
8. “A framework for creating an ad-hoc network of nearby iOS & OS X devices” Multipeer Connectivity Overview - Me, just now
9. Multipeer Connectivity Overview Wi-Fi Bluetooth Peer-to-Peer Wi-Fi R.Y.O.N.N.
10. Multipeer Connectivity Overview Wi-Fi Bluetooth Peer-to-Peer Wi-Fi R.Y.O.N.N. It’s Magic!
11. “A framework for creating an ad-hoc network of that allows nearby iOS & OS X devices to communicate” Multipeer Connectivity Overview - Me, (again), just now
12. Multipeer Connectivity Overview Why does it matter?
13. ✉️ ✉️ ✉️ Multipeer Connectivity Overview ✉️
14. ✉️ ✉️ ✉️ Multipeer Connectivity Overview ✉️ ☁
15. ✉️ ✉️ ✉️ Multipeer Connectivity Overview ✉️
16. ✉️ ✉️ ✉️ Multipeer Connectivity Overview
17. ✉️ ✉️ ✉️ Multipeer Connectivity Overview
18. Multipeer Connectivity Overview MOREEfficient Secure
19. Multipeer Connectivity Overview
20. Multipeer Connectivity Lifecycle
21. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
22. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
23. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate ? ?
24. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate ✅ ✅
25. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
26. Multipeer Connectivity Lifecycle Advertise Discover Invite Connect Communicate
27. Multipeer Connectivity Implement
28. Multipeer Connectivity Implement @import MultipeerConnectivity; Step 0: Import Framework
29. Multipeer Connectivity Implement MCPeerID peerID = [[MCPeerID alloc] initWithDisplayName:peerName]; Step 1: Create Identity
30. Multipeer Connectivity Implement MCSession session = [[MCSession alloc] initWithPeer:peerID]; Step 2: Create Session
31. Multipeer Connectivity Implement MCAdvertiserAssistant advertiser = [[MCAdvertiserAssistant alloc] initWithServiceType:serviceType discoveryInfo:nil session:session]; advertiser.delegate = self; [advertiser start]; Step 3: Advertise
32. 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
33. Multipeer Connectivity Implement MCSession Step 5: Communicate Message Stream Resources
34. 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
35. Multipeer Connectivity Implement MCSessionDelegate // Receive Message -(void) session:(MCSession *)session didReceiveData:(NSData *)data fromPeer:(MCPeerID *)peerID { // Unarchive data to object } Step 5: Communicate
36. Multipeer Connectivity Implement MCSession // Create Stream NSOutputStream *stream = [session startStreamWithName:streamName toPeer:peerID error:&error] // write to stream Step 5: Communicate
37. Multipeer Connectivity Implement MCSessionDelegate // Receive on stream - (void)session:(MCSession *)session didReceiveStream:(NSInputStream *)stream withName:(NSString *)name fromPeer:(MCPeerID *)peerID Step 5: Communicate
38. 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
39. Multipeer Connectivity Implement MCSessionDelegate // Receiving Resource - (void)session:(MCSession *)session didStartReceivingResourceWithName:(NSString *) resourceName:(NSString *) fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *) prg Step 5: Communicate
40. 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
41. Multipeer Connectivity Implement MCSession // Leave Session [session disconnect]; Step 5: Connection Status
42. Multipeer Connectivity Implement MCSessionDelegate // Someone left the session -(void) session:(MCSession *) peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state; { // MCSessionStateNotConnected // MCSessionStateConnecting // MCSessionStateConnected } Step 5: Connection Status
43. Multipeer Connectivity Implement MCSession // handle changes on the main thread dispatch_async(dispatch_get_main_queue(), ^{ [self doThingWithData]; }); Step 5: Communicate !
44. D V M Multipeer Connectivity
45. D V M emo inimum iable Multipeer Connectivity
46. Multipeer Connectivity Demo
47. Multipeer Connectivity Demo Bob Mary Bob Mary Jay
48. Multipeer Connectivity Demo Bob Mary Bob Mary Jay
49. Multipeer Connectivity Demo Bob Mary Jay
50. Multipeer Connectivity Demo Bob Mary Jay
51. Multipeer Connectivity Demo Bob Mary Jay
52. Multipeer Connectivity Demo Bob Mary Jay
53. Multipeer Connectivity Demo
54. Extra Credit Some things we didn’t cover •Programmatic advertising, discovery and session joining (app specific) •Streaming data •Sending resources !
55. Higher Learning Topics to Google •NSHipster •WWDC 2013 (Talk 708) •WWDC 2014 (Talk 709) •objc.io #8 Quadcopter Project •Apple Docs (MP Framework)
56. @jaythrash jay@jaythrash.com http://jaythrash.com/talks
57. Thanks! @jaythrash jay@jaythrash.com http://jaythrash.com/talks