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|
package main
import (
"encoding/json"
"fmt"
"log"
"os"
"sync/atomic"
"time"
"github.com/pion/webrtc/v3"
)
const (
bufferedAmountLowThreshold uint64 = 512 * 1024 // 512 KB
maxBufferedAmount uint64 = 1024 * 1024 // 1 MB
)
func check(err error) {
if err != nil {
panic(err)
}
}
func setRemoteDescription(pc *webrtc.PeerConnection, sdp []byte) {
var desc webrtc.SessionDescription
err := json.Unmarshal(sdp, &desc)
check(err)
// Apply the desc as the remote description
err = pc.SetRemoteDescription(desc)
check(err)
}
func createOfferer() *webrtc.PeerConnection {
// Prepare the configuration
config := webrtc.Configuration{
ICEServers: []webrtc.ICEServer{},
}
// Create a new PeerConnection
pc, err := webrtc.NewPeerConnection(config)
check(err)
buf := make([]byte, 1024)
ordered := false
maxRetransmits := uint16(0)
options := &webrtc.DataChannelInit{
Ordered: &ordered,
MaxRetransmits: &maxRetransmits,
}
sendMoreCh := make(chan struct{})
// Create a datachannel with label 'data'
dc, err := pc.CreateDataChannel("data", options)
check(err)
// Register channel opening handling
dc.OnOpen(func() {
log.Printf("OnOpen: %s-%d. Start sending a series of 1024-byte packets as fast as it can\n", dc.Label(), dc.ID())
for {
err2 := dc.Send(buf)
check(err2)
if dc.BufferedAmount()+uint64(len(buf)) > maxBufferedAmount {
// Wait until the bufferedAmount becomes lower than the threshold
<-sendMoreCh
}
}
})
// Set bufferedAmountLowThreshold so that we can get notified when
// we can send more
dc.SetBufferedAmountLowThreshold(bufferedAmountLowThreshold)
// This callback is made when the current bufferedAmount becomes lower than the threshold
dc.OnBufferedAmountLow(func() {
sendMoreCh <- struct{}{}
})
return pc
}
func createAnswerer() *webrtc.PeerConnection {
// Prepare the configuration
config := webrtc.Configuration{
ICEServers: []webrtc.ICEServer{},
}
// Create a new PeerConnection
pc, err := webrtc.NewPeerConnection(config)
check(err)
pc.OnDataChannel(func(dc *webrtc.DataChannel) {
var totalBytesReceived uint64
// Register channel opening handling
dc.OnOpen(func() {
log.Printf("OnOpen: %s-%d. Start receiving data", dc.Label(), dc.ID())
since := time.Now()
// Start printing out the observed throughput
for range time.NewTicker(1000 * time.Millisecond).C {
bps := float64(atomic.LoadUint64(&totalBytesReceived)*8) / time.Since(since).Seconds()
log.Printf("Throughput: %.03f Mbps", bps/1024/1024)
}
})
// Register the OnMessage to handle incoming messages
dc.OnMessage(func(dcMsg webrtc.DataChannelMessage) {
n := len(dcMsg.Data)
atomic.AddUint64(&totalBytesReceived, uint64(n))
})
})
return pc
}
func main() {
offerPC := createOfferer()
defer func() {
if err := offerPC.Close(); err != nil {
fmt.Printf("cannot close offerPC: %v\n", err)
}
}()
answerPC := createAnswerer()
defer func() {
if err := answerPC.Close(); err != nil {
fmt.Printf("cannot close answerPC: %v\n", err)
}
}()
// Set ICE Candidate handler. As soon as a PeerConnection has gathered a candidate
// send it to the other peer
answerPC.OnICECandidate(func(i *webrtc.ICECandidate) {
if i != nil {
check(offerPC.AddICECandidate(i.ToJSON()))
}
})
// Set ICE Candidate handler. As soon as a PeerConnection has gathered a candidate
// send it to the other peer
offerPC.OnICECandidate(func(i *webrtc.ICECandidate) {
if i != nil {
check(answerPC.AddICECandidate(i.ToJSON()))
}
})
// Set the handler for Peer connection state
// This will notify you when the peer has connected/disconnected
offerPC.OnConnectionStateChange(func(s webrtc.PeerConnectionState) {
fmt.Printf("Peer Connection State has changed: %s (offerer)\n", s.String())
if s == webrtc.PeerConnectionStateFailed {
// Wait until PeerConnection has had no network activity for 30 seconds or another failure. It may be reconnected using an ICE Restart.
// Use webrtc.PeerConnectionStateDisconnected if you are interested in detecting faster timeout.
// Note that the PeerConnection may come back from PeerConnectionStateDisconnected.
fmt.Println("Peer Connection has gone to failed exiting")
os.Exit(0)
}
})
// Set the handler for Peer connection state
// This will notify you when the peer has connected/disconnected
answerPC.OnConnectionStateChange(func(s webrtc.PeerConnectionState) {
fmt.Printf("Peer Connection State has changed: %s (answerer)\n", s.String())
if s == webrtc.PeerConnectionStateFailed {
// Wait until PeerConnection has had no network activity for 30 seconds or another failure. It may be reconnected using an ICE Restart.
// Use webrtc.PeerConnectionStateDisconnected if you are interested in detecting faster timeout.
// Note that the PeerConnection may come back from PeerConnectionStateDisconnected.
fmt.Println("Peer Connection has gone to failed exiting")
os.Exit(0)
}
})
// Now, create an offer
offer, err := offerPC.CreateOffer(nil)
check(err)
check(offerPC.SetLocalDescription(offer))
desc, err := json.Marshal(offer)
check(err)
setRemoteDescription(answerPC, desc)
answer, err := answerPC.CreateAnswer(nil)
check(err)
check(answerPC.SetLocalDescription(answer))
desc2, err := json.Marshal(answer)
check(err)
setRemoteDescription(offerPC, desc2)
// Block forever
select {}
}
|
