Synchronizing without internet - Multipeer Connectivity (iOS)
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The document discusses using Multipeer Connectivity to synchronize data between iOS devices without an internet connection. It provides an overview of Multipeer Connectivity and its classes for discovery, advertising, and sharing data in sessions between nearby peers. Examples are given for sharing images, streaming data, and building a shared whiteboard app using gestures and drawings sent over Multipeer Connectivity sessions. Further examples are mentioned for simple synchronization of data between devices and using third party libraries to enable syncing of Core Data apps.
![MCPeerId
MCPeerID *peerId =
[[MCPeerID alloc] initWithDisplayName:self.deviceName];](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-20-320.jpg)
![MCSession
MCSession *session =
[[MCSession alloc] initWithPeer:self.peerId];
session.delegate = self;](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-21-320.jpg)
![MCBrowserViewController
NSString * const serviceIdentifier = @"codemotion-demo";
MCBrowserViewController *browser =
[[MCBrowserViewController alloc] initWithServiceType:serviceIdentifier
session:self.appdelegate.session];
browser.delegate = self;
[self presentViewController:browser animated:YES completion:nil];](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-25-320.jpg)
![MCAdvertiserAssistant
NSString * const serviceIdentifier = @"codemotion-demo";
MCAdvertiserAssistant *advertiser =
[[MCAdvertiserAssistant alloc]
initWithServiceType:self.serviceIdentifier
discoveryInfo:nil session:session];
[advertiser start];](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-29-320.jpg)
![- (IBAction)choosePhoto:(UIButton *)sender
{
UIImagePickerController *picker = [[UIImagePickerController alloc] init];
picker.delegate = self;
picker.allowsEditing = NO;
picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
picker.mediaTypes = @[(NSString *)kUTTypeImage];
[self presentViewController:picker animated:YES completion:nil];
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-39-320.jpg)
![<UIImagePickerDelegate>
#pragma mark - UIImagePickerDelegate
- (void)imagePickerController:(UIImagePickerController *)picker
didFinishPickingMediaWithInfo:(NSDictionary *)info
{
UIImage *selectedImage = info[UIImagePickerControllerOriginalImage];
NSData *jpegImg = UIImageJPEGRepresentation(selectedImage, 0.5);
NSString *tmpPath = [NSTemporaryDirectory() stringByAppendingString:@"pic.jpg"];
self.imageURL = [NSURL fileURLWithPath:tmpPath];
[jpegImg writeToURL:self.imageURL atomically:NO];
self.picture.image = selectedImage;
[picker dismissViewControllerAnimated:YES completion:nil];
}
- (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker {
[picker dismissViewControllerAnimated:YES completion:NULL];
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-40-320.jpg)
![<MCSessionDelegate>
#pragma mark -
- (void)session:(MCSession *)session
didStartReceivingResourceWithName:(NSString *)resourceName
fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *)progress
{
dispatch_async(dispatch_get_main_queue(), ^{
self.picture.image = nil;
self.picture.backgroundColor = [UIColor yellowColor];
});
}
- (void)session:(MCSession *)session
didFinishReceivingResourceWithName:(NSString *)resourceName
fromPeer:(MCPeerID *)peerID atURL:(NSURL *)localURL
withError:(NSError *)error
{
NSData *data = [NSData dataWithContentsOfURL:localURL];
UIImage *image =
[[UIImage alloc] initWithData:data];
dispatch_async(dispatch_get_main_queue(), ^{
self.picture.image = image;
});
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-41-320.jpg)
![NSOutputStream: open
- (void)session:(MCSession *)session
peer:(MCPeerID *)peerID
didChangeState:(MCSessionState)state
{
...
if (state == MCSessionStateConnected)
{
NSError *error;
NSOutputStream *output =
[session startStreamWithName:@"streamName" toPeer:peer error:&error];
if (error) { return; }
[output scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode];
[output open];
}
...
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-45-320.jpg)
![NSOutputStream: write
NSData *data = [NSData data];
[self.output write:data.bytes maxLength:data.length];](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-46-320.jpg)
![NSInputStream
- (void)session:(MCSession *)session
didReceiveStream:(NSInputStream *)stream
withName:(NSString *)streamName
fromPeer:(MCPeerID *)peerID
{
stream.delegate = self;
[stream scheduleInRunLoop:[NSRunLoop mainRunLoop]
forMode:NSDefaultRunLoopMode];
[stream open];
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-47-320.jpg)
![<NSStreamDelegate>
- (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode
{
switch (eventCode) {
case NSStreamEventOpenCompleted:
...
case NSStreamEventEndEncountered:
...
case NSStreamEventHasBytesAvailable:
{
NSInputStream *inputStream = (NSInputStream *)aStream;
uint8_t buffer[1024];
NSInteger size = [inputStream read:(uint8_t *)buffer maxLength:1024];
NSData *data = [NSData dataWithBytes:buffer length:size];
...
// Manage data received
...
break;
}
default:
break;
}
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-48-320.jpg)
![UIPanGestureRecognizer
- (IBAction)panReceived:(UIPanGestureRecognizer *)sender
{
CGPoint point = [sender locationInView:sender.view];
[self.drawable drawPoint:point state:sender.state];
NSData *data =
[NSData drawDataWithGestureState:sender.state
point:[sender locationInView:sender.view]];
[self.output write:data.bytes maxLength:data.length];
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-51-320.jpg)
![- (void)drawPoint:(CGPoint)point state:(UIGestureRecognizerState)state
{
switch (state) {
case UIGestureRecognizerStateBegan:
{
lastPoint = point;
break;
}
case UIGestureRecognizerStateChanged:
{
CGPoint currentPoint = point;
UIGraphicsBeginImageContext(self.layout.frame.size);
[self.tmpLayout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height)];
CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y);
CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y);
CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound);
CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 10);
CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0, 0, 0, 1.0);
CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal);
CGContextStrokePath(UIGraphicsGetCurrentContext());
self.tmpLayout.image = UIGraphicsGetImageFromCurrentImageContext();
[self.tmpLayout setAlpha:1];
UIGraphicsEndImageContext();
lastPoint = currentPoint;
break;
}
case UIGestureRecognizerStateEnded:
{
UIGraphicsBeginImageContext(self.layout.frame.size);
[self.layout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
[self.tmpLayout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0];
self.layout.image = UIGraphicsGetImageFromCurrentImageContext();
self.tmpLayout.image = nil;
UIGraphicsEndImageContext();
break;
}
default:
break;
}
}](https://image.slidesharecdn.com/codemotion2014-141123133642-conversion-gate01/85/Synchronizing-without-internet-Multipeer-Connectivity-iOS-52-320.jpg)
Synchronizing without internet - Multipeer Connectivity (iOS)
- 1. Synchronizing without internet Codemotion 2014, Madrid
- 2. Who am I? Jorge Maroto (@patoroco) http://maroto.me · iOS Developer @ticketeaeng · Playing with iOS since 2010 · Fanboy
- 3. Synchronize
- 7. ¿Internet?
- 8. LAN (wired / wi-fi)
- 10. Changelog · iOS 3: Game Kit · iOS 4: Game Center · iOS 5: Core Bluetooth · iOS 6: Core Bluetooth advertising · iOS 7: Multipeer Connectivity & iBeacons · iOS 8: Handoff
- 11. Changelog · iOS 3: Game Kit · iOS 4: Game Center · iOS 5: Core Bluetooth · iOS 6: Core Bluetooth advertising · iOS 7: Multipeer Connectivity & iBeacons · iOS 8: Handoff
- 13. Multipeer connectivity · Appears in iOS7. · Ability to connect to a mesh of peers. · Able to connect to peers over WiFi, ad-hoc wireless, and Bluetooth. · Doesn't require server infraestructure. · Peers must be 'nearby'.
- 16. MultipeerConnectivity.framework Bonjour | CFNetwork
- 17. Two phases · Discovery · Session
- 18. Classes #import <MultipeerConnectivity/MultipeerConnectivity.h> Session info Discovery Advertisement
- 19. Session info · MCPeerId · MCSession
- 20. MCPeerId MCPeerID *peerId = [[MCPeerID alloc] initWithDisplayName:self.deviceName];
- 21. MCSession MCSession *session = [[MCSession alloc] initWithPeer:self.peerId]; session.delegate = self;
- 22. <MCSessionDelegate> - (void)session:(MCSession *)session peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state { switch (state): { case MCSessionStateConnected: ... case MCSessionStateConnecting: ... case MCSessionStateNotConnected: ... } }
- 23. <MCSessionDelegate> // DATA - (void)session:(MCSession *)session didReceiveData:(NSData *)data fromPeer:(MCPeerID *)peerID {} // RESOURCES - (void)session:(MCSession *)session didStartReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *)progress {} - (void)session:(MCSession *)session didFinishReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID atURL:(NSURL *)localURL withError:(NSError *)error{} // STREAMS - (void)session:(MCSession *)session didReceiveStream:(NSInputStream *)stream withName:(NSString *)streamName fromPeer:(MCPeerID *)peerID{}
- 24. Discovery · MCBrowserViewController · MCNearbyServiceBrowser
- 25. MCBrowserViewController NSString * const serviceIdentifier = @"codemotion-demo"; MCBrowserViewController *browser = [[MCBrowserViewController alloc] initWithServiceType:serviceIdentifier session:self.appdelegate.session]; browser.delegate = self; [self presentViewController:browser animated:YES completion:nil];
- 27. <MCBrowserViewControllerDelegate> - (void)browserViewControllerDidFinish:(MCBrowserViewController *)b {} - (void)browserViewControllerWasCancelled:(MCBrowserViewController *)b {}
- 28. Advertisement · MCAdvertiserAssistant · MCNearbyServicesAdvertiser
- 29. MCAdvertiserAssistant NSString * const serviceIdentifier = @"codemotion-demo"; MCAdvertiserAssistant *advertiser = [[MCAdvertiserAssistant alloc] initWithServiceType:self.serviceIdentifier discoveryInfo:nil session:session]; [advertiser start];
- 30. Session phase
- 31. Sending data · NSData to an array of peers. · NSURL resource to a peer. · NSStream to a peer.
- 32. Send NSData to an array of peers - (BOOL)sendData:(NSData *)data toPeers:(NSArray *)peerIDs withMode:(MCSessionSendDataMode)mode error:(NSError **)error; Modes · MCSessionSendDataReliable · MCSessionSendDataUnreliable
- 33. DEMO Hello world in MC
- 34. Video
- 36. Send resource to a peer - (NSProgress *)sendResourceAtURL:(NSURL *)resourceURL withName:(NSString *)resourceName toPeer:(MCPeerID *)peerID withCompletionHandler:(void(^)(NSError *error))completionHandler;
- 37. Example Share images from photo library
- 38. @property (weak, nonatomic) IBOutlet UIImageView *picture;
- 39. - (IBAction)choosePhoto:(UIButton *)sender { UIImagePickerController *picker = [[UIImagePickerController alloc] init]; picker.delegate = self; picker.allowsEditing = NO; picker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary; picker.mediaTypes = @[(NSString *)kUTTypeImage]; [self presentViewController:picker animated:YES completion:nil]; }
- 40. <UIImagePickerDelegate> #pragma mark - UIImagePickerDelegate - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info { UIImage *selectedImage = info[UIImagePickerControllerOriginalImage]; NSData *jpegImg = UIImageJPEGRepresentation(selectedImage, 0.5); NSString *tmpPath = [NSTemporaryDirectory() stringByAppendingString:@"pic.jpg"]; self.imageURL = [NSURL fileURLWithPath:tmpPath]; [jpegImg writeToURL:self.imageURL atomically:NO]; self.picture.image = selectedImage; [picker dismissViewControllerAnimated:YES completion:nil]; } - (void)imagePickerControllerDidCancel:(UIImagePickerController *)picker { [picker dismissViewControllerAnimated:YES completion:NULL]; }
- 41. <MCSessionDelegate> #pragma mark - - (void)session:(MCSession *)session didStartReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID withProgress:(NSProgress *)progress { dispatch_async(dispatch_get_main_queue(), ^{ self.picture.image = nil; self.picture.backgroundColor = [UIColor yellowColor]; }); } - (void)session:(MCSession *)session didFinishReceivingResourceWithName:(NSString *)resourceName fromPeer:(MCPeerID *)peerID atURL:(NSURL *)localURL withError:(NSError *)error { NSData *data = [NSData dataWithContentsOfURL:localURL]; UIImage *image = [[UIImage alloc] initWithData:data]; dispatch_async(dispatch_get_main_queue(), ^{ self.picture.image = image; }); }
- 42. Video Share images from photo library
- 44. Streaming - (NSOutputStream *)startStreamWithName:(NSString *)streamName toPeer:(MCPeerID *)peerID error:(NSError **)error;
- 45. NSOutputStream: open - (void)session:(MCSession *)session peer:(MCPeerID *)peerID didChangeState:(MCSessionState)state { ... if (state == MCSessionStateConnected) { NSError *error; NSOutputStream *output = [session startStreamWithName:@"streamName" toPeer:peer error:&error]; if (error) { return; } [output scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode]; [output open]; } ... }
- 46. NSOutputStream: write NSData *data = [NSData data]; [self.output write:data.bytes maxLength:data.length];
- 47. NSInputStream - (void)session:(MCSession *)session didReceiveStream:(NSInputStream *)stream withName:(NSString *)streamName fromPeer:(MCPeerID *)peerID { stream.delegate = self; [stream scheduleInRunLoop:[NSRunLoop mainRunLoop] forMode:NSDefaultRunLoopMode]; [stream open]; }
- 48. <NSStreamDelegate> - (void)stream:(NSStream *)aStream handleEvent:(NSStreamEvent)eventCode { switch (eventCode) { case NSStreamEventOpenCompleted: ... case NSStreamEventEndEncountered: ... case NSStreamEventHasBytesAvailable: { NSInputStream *inputStream = (NSInputStream *)aStream; uint8_t buffer[1024]; NSInteger size = [inputStream read:(uint8_t *)buffer maxLength:1024]; NSData *data = [NSData dataWithBytes:buffer length:size]; ... // Manage data received ... break; } default: break; } }
- 51. UIPanGestureRecognizer - (IBAction)panReceived:(UIPanGestureRecognizer *)sender { CGPoint point = [sender locationInView:sender.view]; [self.drawable drawPoint:point state:sender.state]; NSData *data = [NSData drawDataWithGestureState:sender.state point:[sender locationInView:sender.view]]; [self.output write:data.bytes maxLength:data.length]; }
- 52. - (void)drawPoint:(CGPoint)point state:(UIGestureRecognizerState)state { switch (state) { case UIGestureRecognizerStateBegan: { lastPoint = point; break; } case UIGestureRecognizerStateChanged: { CGPoint currentPoint = point; UIGraphicsBeginImageContext(self.layout.frame.size); [self.tmpLayout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height)]; CGContextMoveToPoint(UIGraphicsGetCurrentContext(), lastPoint.x, lastPoint.y); CGContextAddLineToPoint(UIGraphicsGetCurrentContext(), currentPoint.x, currentPoint.y); CGContextSetLineCap(UIGraphicsGetCurrentContext(), kCGLineCapRound); CGContextSetLineWidth(UIGraphicsGetCurrentContext(), 10); CGContextSetRGBStrokeColor(UIGraphicsGetCurrentContext(), 0, 0, 0, 1.0); CGContextSetBlendMode(UIGraphicsGetCurrentContext(),kCGBlendModeNormal); CGContextStrokePath(UIGraphicsGetCurrentContext()); self.tmpLayout.image = UIGraphicsGetImageFromCurrentImageContext(); [self.tmpLayout setAlpha:1]; UIGraphicsEndImageContext(); lastPoint = currentPoint; break; } case UIGestureRecognizerStateEnded: { UIGraphicsBeginImageContext(self.layout.frame.size); [self.layout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0]; [self.tmpLayout.image drawInRect:CGRectMake(0, 0, self.layout.frame.size.width, self.layout.frame.size.height) blendMode:kCGBlendModeNormal alpha:1.0]; self.layout.image = UIGraphicsGetImageFromCurrentImageContext(); self.tmpLayout.image = nil; UIGraphicsEndImageContext(); break; } default: break; } }
- 53. - (void)clearScreen { UIGraphicsBeginImageContext(self.layout.frame.size); CGContextRef ctx = UIGraphicsGetCurrentContext(); CGContextSetRGBFillColor(ctx, 255.0, 255.0, 255.0, 1.0); CGContextFillRect(ctx, CGRectMake(0, 0, self.tmpLayout.frame.size.width, self.tmpLayout.frame.size.height)); self.layout.image = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); }
- 56. All together
- 57. 'simple sync' example · n-devices. · Create a hash by each register based in time. · First sync in batch using a file. · NSOutputstream to send 'ligth data'. · Off and on send counters & timers using MCSessionSendDataReliable.
- 58. 'simple sync' example · n-devices. · Create a hash by each register based in time. · First sync in batch using a file. · NSOutputstream to send 'ligth data'. · Off and on send counters & timers using MCSessionSendDataReliable.
- 60. Ensembles1 "Sync for Core Data Apps" 1 http://www.ensembles.io
- 61. How far can I ...
- 62. How far can I ... - RADIOUS2. - DevRocket3 ... 2 RADIOUS: https://itunes.apple.com/nz/app/radious-walkie-talkie/ id738480541?mt=8. 3 DeckRocket: https://github.com/jpsim/DeckRocket.
- 63. Questions ?
- 64. Thanks @patoroco