Please refer to Nearby Connections about how to setup Nearby Connections.

Short Messages

Nearby Connections allows its clients to send data within 131 bytes without establishing a connection to the remote device. Please refer to the flow below as how to transfer messages within 131 bytes.

Publisher

class Publisher {
  let connectionManager: ConnectionManager
  let advertiser: Advertiser

  init() {
    connectionManager = ConnectionManager(serviceID: <SERVICE_ID>, strategy: .pointToPoint)
    advertiser = Advertiser(connectionManager: connectionManager)
  }

  func startPublishing() {
    advertiser.startAdvertising(using: <MESSAGE_DATA>)
  }

  func stopPublishing() {
    advertiser.stopAdvertising()
  }
}

Subscriber

class Subscriber {
  let connectionManager: ConnectionManager
  let discoverer: Discoverer

  init() {
    connectionManager = ConnectionManager(serviceID: <SERVICE_ID>, strategy: .pointToPoint)

    discoverer = Discoverer(connectionManager: connectionManager)
    discoverer.delegate = self
  }

  func startSubscription() {
    discoverer.startDiscovery()
  }

  func stopSubscription() {
    discoverer.stopDiscovery()
  }
}

extension Subscriber: DiscovererDelegate {
  func discoverer(_ discoverer: Discoverer, didFind endpointID: EndpointID, with context: Data) {
    // A remote advertising endpoint is found.
    print(context)  // `context` is the published message data.
  }

  func discoverer(_ discoverer: Discoverer, didLose endpointID: EndpointID) {
    // A previously discovered endpoint has gone away.
  }
}

Long Messages

For messages which are larger than 131 bytes, a connection between the devices needs to be established to transfer the message. Please refer to the flow below as how to transfer large data using Nearby Connections.

Publisher

class Publisher {
  let connectionManager: ConnectionManager
  let advertiser: Advertiser

  init() {
    connectionManager = ConnectionManager(serviceID: <SERVICE_ID>, strategy: .pointToPoint)
    connectionManager.delegate = self

    advertiser = Advertiser(connectionManager: connectionManager)
    advertiser.delegate = self
  }

  func startPublishing() {
    advertiser.startAdvertising(using: <ENDPOINT_INFO>)
  }

  func stopPublishing() {
    advertiser.stopAdvertising()
  }
}

extension Publisher: ConnectionManagerDelegate {
  func connectionManager(
    _ connectionManager: ConnectionManager, didReceive data: Data, withID payloadID: PayloadID,
    from endpointID: EndpointID) {
    // We can ignore implementation, because we are the publisher.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didReceive stream: InputStream,
    withID payloadID: PayloadID,
    from endpointID: EndpointID, cancellationToken token: CancellationToken) {
    // We can ignore implementation, because we are the publisher.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didStartReceivingResourceWithID payloadID: PayloadID,
    from endpointID: EndpointID, at localURL: URL, withName name: String,
    cancellationToken token: CancellationToken) {
    // We can ignore implementation, because we are the publisher.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didReceiveTransferUpdate update: TransferUpdate,
    from endpointID: EndpointID, forPayload payloadID: PayloadID) {
    // We can ignore implementation, because we are the publisher.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didChangeTo state: ConnectionState,
    for endpointID: EndpointID) {
    switch state {
    case .connecting:
      // A connection to the remote endpoint is currently being established.
    case .connected:
      // We're connected! Can now start sending and receiving data.
      connectionManager.send(<MESSAGE_DATA>, to: [endpointID])
    case .disconnected:
      // We've been disconnected from this endpoint. No more data can be sent or received.
    case .rejected:
      // The connection was rejected by one or both sides.
    }
  }
}

extension Publisher: AdvertiserDelegate {
  func advertiser(
    _ advertiser: Advertiser, didReceiveConnectionRequestFrom endpointID: EndpointID,
    with context: Data, connectionRequestHandler: @escaping (Bool) -> Void) {
    // Automatically accept any incoming connection requests.
    connectionRequestHandler(true)
  }
}

Subscriber

class Subscriber {
  let connectionManager: ConnectionManager
  let discoverer: Discoverer

  init() {
    connectionManager = ConnectionManager(serviceID: <SERVICE_ID>, strategy: .pointToPoint)
    connectionManager.delegate = self

    discoverer = Discoverer(connectionManager: connectionManager)
    discoverer.delegate = self
  }

  func startSubscription() {
    discoverer.startDiscovery()
  }

  func stopSubscription() {
    discoverer.stopDiscovery()
  }
}

extension Subscriber: ConnectionManagerDelegate {
  func connectionManager(
    _ connectionManager: ConnectionManager, didReceive data: Data, withID payloadID: PayloadID,
    from endpointID: EndpointID) {
    // This always gets the full data of the payload.
    print(data)
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didReceive stream: InputStream,
    withID payloadID: PayloadID,
    from endpointID: EndpointID, cancellationToken token: CancellationToken) {
    // We can ignore implementation because we only care about bytes payloads.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didStartReceivingResourceWithID payloadID: PayloadID,
    from endpointID: EndpointID, at localURL: URL, withName name: String,
    cancellationToken token: CancellationToken) {
    // We can ignore implementation because we only care about bytes payloads.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didReceiveTransferUpdate update: TransferUpdate,
    from endpointID: EndpointID, forPayload payloadID: PayloadID) {
    // Bytes payloads are sent as a single chunk, so you'll receive TransferUpdate.success
    // immediately.
  }

  func connectionManager(
    _ connectionManager: ConnectionManager, didChangeTo state: ConnectionState,
    for endpointID: EndpointID) {
    switch state {
    case .connecting:
      // A connection to the remote endpoint is currently being established.
    case .connected:
      // We're connected! Can now start sending and receiving data.
    case .disconnected:
      // We've been disconnected from this endpoint. No more data can be sent or received.
    case .rejected:
      // The connection was rejected by one or both sides.
    }
  }
}

extension Subscriber: DiscovererDelegate {
  func discoverer(_ discoverer: Discoverer, didFind endpointID: EndpointID, with context: Data) {
    // An endpoint was found. We request a connection to it.
    discoverer.requestConnection(to: endpointID, using: <ENDPOINT_INFO>)
  }

  func discoverer(_ discoverer: Discoverer, didLose endpointID: EndpointID) {
    // A previously discovered endpoint has gone away.
  }
}