pion · o-u-p · Jan 17, 2025 · JoeTurki · Jan 17, 2025 · KevinVison
diff --git a/examples/delete-transceiver/README.md b/examples/delete-transceiver/README.md
@@ -0,0 +1,18 @@
+# delete-transceiver
+delete-transceiver demonstrates Pion WebRTC's ability to delete rejected transceivers.
+
+## Instructions
+
+### Download delete-transceiver
+This example requires you to clone the repo since it is serving static HTML.
+
+```
+git clone https://github.com/pion/webrtc.git
+cd webrtc/examples/delete-transceiver
+```
+
+### Run delete-transceiver
+Execute `go run *.go`
+
+### Open the Web UI
+Open [http://localhost:8080](http://localhost:8080). This remote peerconnection will use single port 8443.
diff --git a/examples/delete-transceiver/index.html b/examples/delete-transceiver/index.html
@@ -0,0 +1,117 @@
+<html>
+<!--
+    SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+    SPDX-License-Identifier: MIT
+  -->
+
+<head>
+  <title>ice-single-port</title>
+</head>
+
+<body>
+  <h3> ICE Selected Pairs </h3>
+  <div id="deleteTransceiver"></div> <br />
+</body>
+
+<script>
+  let removeTransceiverByMid = (sdp, mids) => {
+    const lines = sdp.split('\r\n');
+    const midSet = new Set(mids);
+    let currentMid = null;
+    let firstMid = null;
+    let updatedLines = [];
+    let lastMlineIndex = -1, lastDirectionIndex = -1;
+    let lamda = () => {
+      if (currentMid && midSet.has(currentMid)) {
+        if (currentMid != firstMid) {
+          const mLineParts = updatedLines[lastMlineIndex].split(' ');
+          mLineParts[1] = '0';
+          updatedLines[lastMlineIndex] = mLineParts.join(' ');
+        }
+        updatedLines[lastDirectionIndex] = 'a=inactive';
+        lastMlineIndex = lastDirectionIndex = -1;
+      }
+    };
+    for (let i = 0; i < lines.length; i++) {
+      const line = lines[i];
+      if (line.startsWith('m=')) {
+        lamda();
+        currentMid = null;
+        lastMlineIndex = updatedLines.length;
+        updatedLines.push(line);
+        continue;
+      }
+      if (line.startsWith('a=mid:')) {
+        currentMid = line.substring(6).trim();
+        if (!firstMid) {
+          firstMid = currentMid;
+        }
+      }
+      if (currentMid && midSet.has(currentMid)) {
+        if (line.startsWith('a=ssrc') || line.startsWith('a=ssrc-group')) {
+          continue;
+        }
+        if (line.match(/^a=(sendrecv|sendonly|recvonly|inactive)$/)) {
+          lastDirectionIndex = updatedLines.length;
+          updatedLines.push(line);
+          continue;
+        }
+        updatedLines.push(line);
+      }
+      else {
+        updatedLines.push(line);
+      }
+    }
+    lamda();
+    return updatedLines.join('\r\n');
+  }
+  let pc = new RTCPeerConnection()
+  pc.addTransceiver('video')
+  pc.addTransceiver('audio')
+
+  pc.createOffer()
+    .then(offer => {
+      pc.setLocalDescription(offer)
+
+      return fetch(`/doOffer`, {
+        method: 'post',
+        headers: {
+          'Accept': 'application/json, text/plain, */*',
+          'Content-Type': 'application/json'
+        },
+        body: JSON.stringify(offer)
+      })
+    })
+    .then(res => res.json())
+    .then(res => pc.setRemoteDescription(res))
+    .catch(alert)
+
+  setTimeout(() => {
+    const transceivers = pc.getTransceivers();
+    if (transceivers.length > 1) {
+      const secondTransceiver = transceivers[1];
+
+      // Get the MID of the second transceiver
+      const mid = secondTransceiver.mid;
+
+      sdp = removeTransceiverByMid(pc.localDescription.sdp, [mid]);
+      console.log("updated sdp:", sdp);
+      let offer = { type: "offer", sdp: sdp };
+      pc.setLocalDescription(offer);
+      fetch(`/doUpdate`, {
+        method: 'post',
+        headers: {
+          'Accept': 'application/json, text/plain, */*',
+          'Content-Type': 'application/json'
+        },
+        body: JSON.stringify(offer)
+      }).then(res => res.json())
+        .then(res => pc.setRemoteDescription(res))
+        .catch(alert)
+    } else {
+      console.log("The peer connection does not have a second transceiver.");
+    }
+  }, 3000);
+</script>
+
+</html>
diff --git a/examples/delete-transceiver/main.go b/examples/delete-transceiver/main.go
@@ -0,0 +1,133 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+//go:build !js
+// +build !js
+
+// delete-transceiver demonstrates Pion WebRTC's ability to delete rejected transceivers.
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/pion/ice/v4"
+	"github.com/pion/webrtc/v4"
+)
+
+var api *webrtc.API //nolint
+var peerConnection *webrtc.PeerConnection
+
+// Everything below is the Pion WebRTC API! Thanks for using it ❤️.
+func doOffer(w http.ResponseWriter, r *http.Request) {
+	var err error
+	peerConnection, err = api.NewPeerConnection(webrtc.Configuration{})
+	if err != nil {
+		panic(err)
+	}
+
+	// Set the handler for ICE connection state
+	// This will notify you when the peer has connected/disconnected
+	peerConnection.OnICEConnectionStateChange(func(connectionState webrtc.ICEConnectionState) {
+		fmt.Printf("ICE Connection State has changed: %s\n", connectionState.String())
+	})
+
+	// Send the current time via a DataChannel to the remote peer every 3 seconds
+	peerConnection.OnDataChannel(func(d *webrtc.DataChannel) {
+		d.OnOpen(func() {
+			for range time.Tick(time.Second * 3) {
+				if err = d.SendText(time.Now().String()); err != nil {
+					panic(err)
+				}
+			}
+		})
+	})
+
+	var offer webrtc.SessionDescription
+	if err = json.NewDecoder(r.Body).Decode(&offer); err != nil {
+		panic(err)
+	}
+
+	if err = peerConnection.SetRemoteDescription(offer); err != nil {
+		panic(err)
+	}
+
+	// Create channel that is blocked until ICE Gathering is complete
+	gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
+
+	answer, err := peerConnection.CreateAnswer(nil)
+	if err != nil {
+		panic(err)
+	} else if err = peerConnection.SetLocalDescription(answer); err != nil {
+		panic(err)
+	}
+
+	// Block until ICE Gathering is complete, disabling trickle ICE
+	// we do this because we only can exchange one signaling message
+	// in a production application you should exchange ICE Candidates via OnICECandidate
+	<-gatherComplete
+
+	response, err := json.Marshal(*peerConnection.LocalDescription())
+	if err != nil {
+		panic(err)
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if _, err := w.Write(response); err != nil {
+		panic(err)
+	}
+}
+
+func doUpdate(w http.ResponseWriter, r *http.Request) {
+	var err error
+	var offer webrtc.SessionDescription
+	if err = json.NewDecoder(r.Body).Decode(&offer); err != nil {
+		panic(err)
+	}
+
+	if err = peerConnection.SetRemoteDescription(offer); err != nil {
+		panic(err)
+	}
+
+	answer, err := peerConnection.CreateAnswer(nil)
+	if err != nil {
+		panic(err)
+	} else if err = peerConnection.SetLocalDescription(answer); err != nil {
+		panic(err)
+	}
+	response, err := json.Marshal(answer)
+	if err != nil {
+		panic(err)
+	}
+
+	w.Header().Set("Content-Type", "application/json")
+	if _, err := w.Write(response); err != nil {
+		panic(err)
+	}
+}
+
+func main() {
+	// Create a SettingEngine, this allows non-standard WebRTC behavior
+	settingEngine := webrtc.SettingEngine{}
+
+	// Listen on UDP Port 8443, will be used for all WebRTC traffic
+	mux, err := ice.NewMultiUDPMuxFromPort(8443)
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("Listening for WebRTC traffic at %d\n", 8443)
+	settingEngine.SetICEUDPMux(mux)
+
+	// Create a new API using our SettingEngine
+	api = webrtc.NewAPI(webrtc.WithSettingEngine(settingEngine))
+
+	http.Handle("/", http.FileServer(http.Dir(".")))
+	http.HandleFunc("/doOffer", doOffer)
+	http.HandleFunc("/doUpdate", doUpdate)
+
+	fmt.Println("Open http://localhost:8080 to access this demo")
+	// nolint: gosec
+	panic(http.ListenAndServe(":8080", nil))
+}