Add examples/whip-whep

Create WHIP/WHEP example works with OBS or browser

Resolves #2499

examples/whip-whep/main.go

@@ -0,0 +1,197 @@
+// SPDX-FileCopyrightText: 2023 The Pion community <https://pion.ly>
+// SPDX-License-Identifier: MIT
+
+//go:build !js
+// +build !js
+
+// whip-whep demonstrates how to use the WHIP/WHEP specifications to exhange SPD descriptions and stream media to a WebRTC client in the browser or OBS
+package main
+
+import (
+	"fmt"
+	"io"
+	"net/http"
+
+	"github.com/pion/interceptor"
+	"github.com/pion/interceptor/pkg/intervalpli"
+	"github.com/pion/webrtc/v4"
+)
+
+// nolint: gochecknoglobals
+var (
+	videoTrack *webrtc.TrackLocalStaticRTP
+
+	peerConnectionConfiguration = webrtc.Configuration{
+		ICEServers: []webrtc.ICEServer{
+			{
+				URLs: []string{"stun:stun.l.google.com:19302"},
+			},
+		},
+	}
+)
+
+// nolint:gocognit
+func main() {
+	// Everything below is the Pion WebRTC API! Thanks for using it ❤️.
+	var err error
+	if videoTrack, err = webrtc.NewTrackLocalStaticRTP(webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeH264}, "video", "pion"); err != nil {
+		panic(err)
+	}
+
+	http.Handle("/", http.FileServer(http.Dir(".")))
+	http.HandleFunc("/whep", whepHandler)
+	http.HandleFunc("/whip", whipHandler)
+
+	fmt.Println("Open http://localhost:8080 to access this demo")
+	panic(http.ListenAndServe(":8080", nil)) // nolint: gosec
+}
+
+func whipHandler(w http.ResponseWriter, r *http.Request) {
+	// Read the offer from HTTP Request
+	offer, err := io.ReadAll(r.Body)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a MediaEngine object to configure the supported codec
+	m := &webrtc.MediaEngine{}
+
+	// Setup the codecs you want to use.
+	// We'll only use H264 but you can also define your own
+	if err = m.RegisterCodec(webrtc.RTPCodecParameters{
+		RTPCodecCapability: webrtc.RTPCodecCapability{MimeType: webrtc.MimeTypeH264, ClockRate: 90000, Channels: 0, SDPFmtpLine: "", RTCPFeedback: nil},
+		PayloadType:        96,
+	}, webrtc.RTPCodecTypeVideo); err != nil {
+		panic(err)
+	}
+
+	// Create a InterceptorRegistry. This is the user configurable RTP/RTCP Pipeline.
+	// This provides NACKs, RTCP Reports and other features. If you use `webrtc.NewPeerConnection`
+	// this is enabled by default. If you are manually managing You MUST create a InterceptorRegistry
+	// for each PeerConnection.
+	i := &interceptor.Registry{}
+
+	// Register a intervalpli factory
+	// This interceptor sends a PLI every 3 seconds. A PLI causes a video keyframe to be generated by the sender.
+	// This makes our video seekable and more error resilent, but at a cost of lower picture quality and higher bitrates
+	// A real world application should process incoming RTCP packets from viewers and forward them to senders
+	intervalPliFactory, err := intervalpli.NewReceiverInterceptor()
+	if err != nil {
+		panic(err)
+	}
+	i.Add(intervalPliFactory)
+
+	// Use the default set of Interceptors
+	if err = webrtc.RegisterDefaultInterceptors(m, i); err != nil {
+		panic(err)
+	}
+
+	// Create the API object with the MediaEngine
+	api := webrtc.NewAPI(webrtc.WithMediaEngine(m), webrtc.WithInterceptorRegistry(i))
+
+	// Prepare the configuration
+
+	// Create a new RTCPeerConnection
+	peerConnection, err := api.NewPeerConnection(peerConnectionConfiguration)
+	if err != nil {
+		panic(err)
+	}
+
+	// Allow us to receive 1 video trac
+	if _, err = peerConnection.AddTransceiverFromKind(webrtc.RTPCodecTypeVideo); err != nil {
+		panic(err)
+	}
+
+	// Set a handler for when a new remote track starts, this handler saves buffers to disk as
+	// an ivf file, since we could have multiple video tracks we provide a counter.
+	// In your application this is where you would handle/process video
+	peerConnection.OnTrack(func(track *webrtc.TrackRemote, receiver *webrtc.RTPReceiver) { //nolint: revive
+		for {
+			pkt, _, err := track.ReadRTP()
+			if err != nil {
+				panic(err)
+			}
+
+			if err = videoTrack.WriteRTP(pkt); err != nil {
+				panic(err)
+			}
+		}
+	})
+
+	// Send answer via HTTP Response
+	writeAnswer(w, peerConnection, offer, "/whip")
+}
+
+func whepHandler(w http.ResponseWriter, r *http.Request) {
+	// Read the offer from HTTP Request
+	offer, err := io.ReadAll(r.Body)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a new RTCPeerConnection
+	peerConnection, err := webrtc.NewPeerConnection(peerConnectionConfiguration)
+	if err != nil {
+		panic(err)
+	}
+
+	// Add Video Track that is being written to from WHIP Session
+	rtpSender, err := peerConnection.AddTrack(videoTrack)
+	if err != nil {
+		panic(err)
+	}
+
+	// Read incoming RTCP packets
+	// Before these packets are returned they are processed by interceptors. For things
+	// like NACK this needs to be called.
+	go func() {
+		rtcpBuf := make([]byte, 1500)
+		for {
+			if _, _, rtcpErr := rtpSender.Read(rtcpBuf); rtcpErr != nil {
+				return
+			}
+		}
+	}()
+
+	// Send answer via HTTP Response
+	writeAnswer(w, peerConnection, offer, "/whep")
+}
+
+func writeAnswer(w http.ResponseWriter, peerConnection *webrtc.PeerConnection, offer []byte, path string) {
+	// 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())
+
+		if connectionState == webrtc.ICEConnectionStateFailed {
+			_ = peerConnection.Close()
+		}
+	})
+
+	if err := peerConnection.SetRemoteDescription(webrtc.SessionDescription{Type: webrtc.SDPTypeOffer, SDP: string(offer)}); err != nil {
+		panic(err)
+	}
+
+	// Create channel that is blocked until ICE Gathering is complete
+	gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
+
+	// Create answer
+	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
+
+	// WHIP+WHEP expects a Location header and a HTTP Status Code of 201
+	w.Header().Add("Location", path)
+	w.WriteHeader(http.StatusCreated)
+
+	// Write Answer with Candidates as HTTP Response
+	fmt.Fprint(w, peerConnection.LocalDescription().SDP)
+}