main.go

package main

import (
	"bufio"
	"encoding/base64"
	"fmt"
	"io/ioutil"
	"math/rand"
	"os"
	"time"

	"github.com/pions/webrtc"
	"github.com/pions/webrtc/pkg/ice"
)

func randSeq(n int) string {
	r := rand.New(rand.NewSource(time.Now().UnixNano()))
	letters := []rune("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ")
	b := make([]rune, n)
	for i := range b {
		b[i] = letters[r.Intn(len(letters))]
	}
	return string(b)
}

func main() {

	/* Everything below is the pion-WebRTC API, thanks for using it! */

	// Setup the codecs you want to use.
	// We'll use the default ones but you can also define your own
	webrtc.RegisterDefaultCodecs()

	// Create a new RTCPeerConnection
	peerConnection, err := webrtc.New(webrtc.RTCConfiguration{
		ICEServers: []webrtc.RTCICEServer{
			{
				URLs: []string{"stun:stun.l.google.com:19302"},
			},
		},
	})
	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 ice.ConnectionState) {
		fmt.Printf("Connection State has changed %s \n", connectionState.String())
	}

	offer, err := peerConnection.CreateOffer(nil)
	if err != nil {
		panic(err)
	}

	fmt.Println(base64.StdEncoding.EncodeToString([]byte(offer.Sdp)))

	fmt.Println("Press enter to read sdp.txt as the answer")
	if _, err := bufio.NewReader(os.Stdin).ReadString('\n'); err != nil {
		panic(err)
	}

	rawSdp, err := ioutil.ReadFile("sdp.txt")
	if err != nil {
		panic(err)
	}

	sd, err := base64.StdEncoding.DecodeString(string(rawSdp))
	if err != nil {
		panic(err)
	}

	// Set the remote SessionDescription
	answer := webrtc.RTCSessionDescription{
		Type: webrtc.RTCSdpTypeAnswer,
		Sdp:  string(sd),
	}
	if err := peerConnection.SetRemoteDescription(answer); err != nil {
		panic(err)
	}

	select {}
}