data channel support

Sources/NabtoEdgeClientWebRTC/Impl/EdgeDataChannel.swift

@@ -0,0 +1,58 @@
+//
+//  File.swift
+//  
+//
+//  Created by Ahmad Saleh on 24/06/2024.
+//
+
+import Foundation
+import WebRTC
+
+public class EdgeDataChannelImpl: NSObject, EdgeDataChannel, RTCDataChannelDelegate {
+    internal var dc: RTCDataChannel!
+    public var onMessage: EdgeOnMessageCallback? = nil
+    public var onOpened: EdgeOnOpenedCallback? = nil
+    public var onClosed: EdgeOnClosedCallback? = nil
+
+    public init(_ dataChannel: RTCDataChannel) {
+        self.dc = dataChannel
+        super.init()
+
+        self.dc.delegate = self
+    }
+
+    public func send(_ data: Data) async {
+        let buffer = RTCDataBuffer(data: data, isBinary: true)
+        self.dc.sendData(buffer)
+    }
+
+    public func close() async {
+        self.dc.close()
+    }
+
+    public func dataChannelDidChangeState(_ dataChannel: RTCDataChannel) {
+        EdgeLogger.info("Data channel \(dataChannel.channelId) state changed to \(dataChannel.readyState)")
+        switch dataChannel.readyState {
+        case .connecting:
+            break
+
+        case .open:
+            self.onOpened?()
+            break
+
+        case .closing:
+            break
+
+        case .closed:
+            self.onClosed?()
+            break
+
+        @unknown default:
+            break
+        }
+    }
+
+    public func dataChannel(_ dataChannel: RTCDataChannel, didReceiveMessageWith buffer: RTCDataBuffer) {
+        self.onMessage?(buffer.data)
+    }
+}

Sources/NabtoEdgeClientWebRTC/Impl/EdgePeerConnection.swift

@@ -51,15 +51,15 @@ internal class EdgePeerConnectionImpl: NSObject, EdgePeerConnection {
 
                 let coap = try conn.createCoapRequest(method: "GET", path: "/p2p/webrtc-info")
                 let coapResult = try await coap.executeAsync()
-
+                
                 if coapResult.status != 205 {
                     EdgeLogger.error("Unexpected /p2p/webrtc-info return code \(coapResult.status). Failed to initialize signaling service.")
                     throw EdgeWebrtcError.signalingFailedToInitialize
                 }
-
+                
                 var rtcInfo: RTCInfo
                 let stream = try conn.createStream()
-
+                
                 let cborDecoder = CBORDecoder()
                 let jsonDecoder = JSONDecoder()
                 if coapResult.contentFormat == 50 {
@@ -71,7 +71,7 @@ internal class EdgePeerConnectionImpl: NSObject, EdgePeerConnection {
                     try stream.close()
                     throw EdgeWebrtcError.signalingFailedToInitialize
                 }
-
+                
                 try await stream.openAsync(streamPort: rtcInfo.signalingStreamPort)
 
                 self.signaling = try await EdgeStreamSignaling(stream)
@@ -86,6 +86,12 @@ internal class EdgePeerConnectionImpl: NSObject, EdgePeerConnection {
         self.conn = nil
     }
 
+    func createDataChannel(_ label: String) throws -> EdgeDataChannel {
+        let config = RTCDataChannelConfiguration()
+        let dc = peerConnection?.dataChannel(forLabel: label, configuration: config)
+        return EdgeDataChannelImpl(dc!)
+    }
+
     private func error(_ err: EdgeWebrtcError, _ msg: String?) {
         if let msg = msg {
             EdgeLogger.error(msg)

Sources/NabtoEdgeClientWebRTC/Interface.swift

@@ -1,6 +1,36 @@
 import Foundation
 import WebRTC
 
+/**
+ * Callback invoked when the remote peer has added a Track to the WebRTC connection
+ *
+ * @param track [in] The newly added Track
+ * @param trackId [in] The device repoted ID for this Track
+ */
+public typealias EdgeOnTrackCallback = (_ track: EdgeMediaTrack, _ trackId: String?) -> ()
+
+/**
+ * Callback invoked when the object (e.g. a data channel) has opened.
+ */
+public typealias EdgeOnOpenedCallback = () -> ()
+
+/**
+ * Callback invoked when a WebRTC connection has been closed
+ */
+ public typealias EdgeOnClosedCallback = () -> ()
+
+/**
+ * Callback invoked when an error occurs in the WebRTC connection
+ *
+ * @param error [in] The Error that occured
+ */
+public typealias EdgeOnErrorCallback = (_ error: EdgeWebrtcError) -> ()
+
+/**
+ * Callback invoked when a data channel has received a message.
+ */
+public typealias EdgeOnMessageCallback = (_ data: Data) -> ()
+
 /**
  * Errors emitted by the onErrorCallback
  */
@@ -91,27 +121,43 @@ public protocol EdgeAudioTrack: EdgeMediaTrack {
     func setEnabled(_ enabled: Bool)
 }
 
-
-/**
- * Callback invoked when the remote peer has added a Track to the WebRTC connection
- *
- * @param track [in] The newly added Track
- * @param trackId [in] The device repoted ID for this Track
- */
-public typealias EdgeOnTrackCallback = (_ track: EdgeMediaTrack, _ trackId: String?) -> ()
-
 /**
- * Callback invoked when a WebRTC connection has been closed
+ * Data channel for sending and receiving bytes on a webrtc connection
  */
- public typealias EdgeOnClosedCallback = () -> ()
-
-/**
- * Callback invoked when an error occurs in the WebRTC connection
- *
- * @param error [in] The Error that occured
- */
-public typealias EdgeOnErrorCallback = (_ error: EdgeWebrtcError) -> ()
-
+public protocol EdgeDataChannel {
+    /**
+     * Set the callback to be invoked when the data channel receives a message.
+     *
+     * @param cb The callback to set
+     */
+    var onMessage: EdgeOnMessageCallback? { get set }
+
+    /**
+     * Set the callback to be invoked when the data channel is open and ready to send/receive messages.
+     *
+     * @param cb The callback to set
+     */
+    var onOpened: EdgeOnOpenedCallback? { get set }
+
+    /**
+     * Set the callback to be invoked when the data channel is closed.
+     *
+     * @param cb The callback to set
+     */
+    var onClosed: EdgeOnClosedCallback? { get set }
+
+    /**
+     * Send a Data byte buffer over the data channel.
+     *
+     * @param data The binary data to be sent.
+     */
+    func send(_ data: Data) async
+
+    /**
+     * Closes the data channel.
+     */
+    func close() async
+}
 
 /**
  * Main Connection interface used to connect to a device and interact with it.
@@ -138,6 +184,14 @@ public protocol EdgePeerConnection {
      * @param cb The callback to set
      */
     var onError: EdgeOnErrorCallback? { get set }
+
+    /**
+     * Create a new data channel
+     * WARNING: Data channels are experimental and may not work as expected..
+     *
+     * @param label A string that describes the data channel.
+     */
+    func createDataChannel(_ label: String) throws -> EdgeDataChannel
 
     /**
      * Establish a WebRTC connection to the other peer