app_webrtc.go

package main

import (
    "fmt"
    "sync"
    "time"

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

func createClient(name string, offerCh chan webrtc.RTCSessionDescription, answerCh chan webrtc.RTCSessionDescription, master bool) {
    peerConnection, err := webrtc.New(webrtc.RTCConfiguration{
        ICEServers: []webrtc.RTCICEServer{ { URLs: []string{"stun:stun.l.google.com:19302"}, }, },
    })
    if err != nil {
        panic(err)
    }

    peerConnection.OnICEConnectionStateChange = func(connectionState ice.ConnectionState) {
        fmt.Printf("Connection State has changed %s \n", connectionState.String())
    }

    datachannels := make([]*webrtc.RTCDataChannel, 0)
    var dataChannelsLock sync.RWMutex

    peerConnection.Ondatachannel = func(d *webrtc.RTCDataChannel) {
        dataChannelsLock.Lock()
        datachannels = append(datachannels, d)
        dataChannelsLock.Unlock()
        fmt.Printf("New DataChannel %s %d\n", d.Label, d.ID)

        d.Lock()
        defer d.Unlock()
        d.Onmessage = func(payload datachannel.Payload) {
            switch p := payload.(type) {
            case *datachannel.PayloadString:
                fmt.Printf("Message '%s' from DataChannel '%s' payload '%s'\n", p.PayloadType().String(), d.Label, string(p.Data))
            case *datachannel.PayloadBinary:
                fmt.Printf("Message '%s' from DataChannel '%s' payload '% 02x'\n", p.PayloadType().String(), d.Label, p.Data)
            default:
                fmt.Printf("Message '%s' from DataChannel '%s' no payload \n", p.PayloadType().String(), d.Label)
            }
        }
    }
    if master {
        offer, err :=peerConnection.CreateOffer(nil)
        if err != nil {
            panic(err)
        }
        // fmt.Println("", name, "webrtc offer ", offer.Sdp)
        offerCh <- offer

        answer := <- answerCh
        if err := peerConnection.SetRemoteDescription(answer); err != nil {
            panic(err)
        }
    } else {
        offer := <- offerCh
        if err := peerConnection.SetRemoteDescription(offer); err != nil {
           panic(err)
        }
        answer, err := peerConnection.CreateAnswer(nil)
        if err != nil {
           panic(err)
        }
        //fmt.Println("", name, "webrtc answer ", answer.Sdp)
        answerCh <- answer
    }

    fmt.Println("Random messages will now be sent to any connected DataChannels every 5 seconds")
    counter := uint64(0)
    for {
        time.Sleep(5 * time.Second)
        message := name + " " + strconv.FormatUint(counter, 10)
        fmt.Printf("%s is sending '%s' \n", name, message)
        dataChannelsLock.RLock()
        for _, d := range datachannels {
            err := d.Send(datachannel.PayloadString{Data: []byte(message)})
            if err != nil {
                panic(err)
            }
        }
        dataChannelsLock.RUnlock()
        counter++
    }
}

func main() {
    webrtc.RegisterDefaultCodecs()
    offer := make(chan webrtc.RTCSessionDescription)
    answer := make(chan webrtc.RTCSessionDescription)
    go createClient("Bob", offer, answer, false)
    createClient("Alice", offer, answer, true)
}

output.log

Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 21296 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 63408 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 21296 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 63408 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 21296 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 63408 176.59.37.29 52450 typ srflx raddr 192.168.43.220 rport 52450 generation 0 Connection State has changed Checking 
Random messages will now be sent to any connected DataChannels every 5 seconds
Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 7832 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 23124 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 7832 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 23124 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 0 udp 7832 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Tried to parse ICE candidate, but failed candidate:udpcandidate 1 udp 23124 176.59.37.29 64667 typ srflx raddr 192.168.43.220 rport 64667 generation 0 Random messages will now be sent to any connected DataChannels every 5 seconds
Connection State has changed Checking 
Connection State has changed Connected 
Connection State has changed Connected 
Alice is sending 'Alice 0' 
Bob is sending 'Bob 0' 
Alice is sending 'Alice 1' 
Bob is sending 'Bob 1' 
Connection State has changed Disconnected 
Alice is sending 'Alice 2' 
Bob is sending 'Bob 2' 
Alice is sending 'Alice 3' 
Bob is sending 'Bob 3' 
Alice is sending 'Alice 4' 
Bob is sending 'Bob 4' 
Alice is sending 'Alice 5' 
Bob is sending 'Bob 5' 
Alice is sending 'Alice 6'