go webrtc sample example

go-webrtc-sample-example.go

package main

import (
	"log"
	"os"
	"os/signal"
	"syscall"

	"github.com/pion/webrtc/v3"
)

func main() {

	offerSDChan := make(chan webrtc.SessionDescription, 1)
	answerSDChan := make(chan webrtc.SessionDescription, 1)

	go func() {
		conn, err := NewConnection()
		panicIf(err)

		conn.OnICECandidate(func(i *webrtc.ICECandidate) {
			log.Println("Offer:OnICECandidate", i)
		})

		conn.OnICEConnectionStateChange(func(is webrtc.ICEConnectionState) {
			log.Println("Offer:OnICEConnectionStateChange", is)
		})

		dataChan, err := conn.CreateDataChannel("mydata", &webrtc.DataChannelInit{})
		panicIf(err)

		dataChan.OnOpen(func() {
			log.Println("Offer:Data: Conection opened")
			err = dataChan.SendText("hello Guys")
			panicIf(err)
		})

		dataChan.OnError(func(err error) {
			log.Println("Offer:data:error", err)
		})

		dataChan.OnClose(func() {
			log.Println("Offer:data:close. Goodbye")
		})

		dataChan.OnMessage(func(msg webrtc.DataChannelMessage) {
			log.Println("Offer:data: Got some message: ")
		})

		sd, err := conn.CreateOffer(nil)
		panicIf(err)

		err = conn.SetLocalDescription(sd)
		panicIf(err)
		log.Println("Offer: Local Set")

		log.Println("Offer:GatheringCompletePromise: started.")
		<-webrtc.GatheringCompletePromise(conn)
		log.Println("Offer:GatheringCompletePromise: done.")
		offerSDChan <- *conn.LocalDescription()

		log.Println("Offer: Waiting for answer SD")
		answerSD := <-answerSDChan
		err = conn.SetRemoteDescription(answerSD)
		panicIf(err)
		log.Println("Offer: remote Set")

	}()

	go func() {
		conn, err := NewConnection()
		panicIf(err)

		conn.OnICECandidate(func(i *webrtc.ICECandidate) {
			log.Println("\tanswer:OnICECandidate", i)
		})

		conn.OnICEConnectionStateChange(func(is webrtc.ICEConnectionState) {
			log.Println("\tanswer:OnICEConnectionStateChange", is)
		})

		conn.OnDataChannel(func(dc *webrtc.DataChannel) {
			log.Println("\tAnswer:data")

			dc.OnMessage(func(msg webrtc.DataChannelMessage) {
				log.Println("\tAnswer:msg:", string(msg.Data))
			})
			dc.OnOpen(func() {
				log.Println("\tAnswer:Data: Conection opened")
			})

			dc.OnError(func(err error) {
				log.Println("\tAnswer:data:error", err)
			})

			dc.OnClose(func() {
				log.Println("\tAnswer:data:close. Goodbye")
			})
		})

		log.Println("\tAnswer: Waiting for offer SD")
		offerSD := <-offerSDChan
		err = conn.SetRemoteDescription(offerSD)
		log.Println("\tAnswer: remote Set")

		ansSD, err := conn.CreateAnswer(nil)
		panicIf(err)

		err = conn.SetLocalDescription(ansSD)
		panicIf(err)
		log.Println("\tAnswer: Local Set")

		log.Println("\tAnswer:GatheringCompletePromise: started.")
		<-webrtc.GatheringCompletePromise(conn)
		log.Println("\tAnswer:GatheringCompletePromise: done.")
		answerSDChan <- *conn.LocalDescription()

	}()

	// ctrl+c to exit
	setupCloseHandler()

}

func NewConnection() (*webrtc.PeerConnection, error) {
	peerConnectionConfig := webrtc.Configuration{
		ICEServers: []webrtc.ICEServer{
			{
				URLs: []string{

					"stun:stun.l.google.com:19302",
					// "stun:stun1.l.google.com:19302",
					// "stun:stun2.l.google.com:19302",
					// "stun:stun3.l.google.com:19302",
					// "stun:stun4.l.google.com:19302",
					// "stun:stun01.sipphone.com",
					// "stun:stun.ekiga.net",
					// "stun:stun.fwdnet.net",
					// "stun:stun.ideasip.com",
					// "stun:stun.iptel.org",
					// "stun:stun.rixtelecom.se",
					// "stun:stun.schlund.de",
					// "stun:stunserver.org",
					// "stun:stun.softjoys.com",
					// "stun:stun.voiparound.com",
					// "stun:stun.voipbuster.com",
					// "stun:stun.voipstunt.com",
					// "stun:stun.voxgratia.org",
					// "stun:stun.xten.com",
				},
			},
		},
	}

	return webrtc.NewPeerConnection(peerConnectionConfig)
}

func panicIf(err error) {
	if err != nil {
		log.Panicln(err)
	}
}

func setupCloseHandler() {
	c := make(chan os.Signal)
	signal.Notify(c, os.Interrupt, syscall.SIGTERM)
	<-c
	os.Exit(0)
}

Thanks to @hnasr (https://www.youtube.com/watch?v=FExZvpVvYxA - amazing video. Must watch).

I've just converted his javascript code to Golang.