1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
|
package main
import (
"encoding/json"
"fmt"
"net/http"
"time"
"github.com/pion/webrtc/v3"
"golang.org/x/net/websocket"
)
// websocketServer is called for every new inbound WebSocket
func websocketServer(ws *websocket.Conn) { // nolint:gocognit
// Create a new RTCPeerConnection
peerConnection, err := webrtc.NewPeerConnection(webrtc.Configuration{})
if err != nil {
panic(err)
}
// When Pion gathers a new ICE Candidate send it to the client. This is how
// ice trickle is implemented. Everytime we have a new candidate available we send
// it as soon as it is ready. We don't wait to emit a Offer/Answer until they are
// all available
peerConnection.OnICECandidate(func(c *webrtc.ICECandidate) {
if c == nil {
return
}
outbound, marshalErr := json.Marshal(c.ToJSON())
if marshalErr != nil {
panic(marshalErr)
}
if _, err = ws.Write(outbound); 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 webrtc.ICEConnectionState) {
fmt.Printf("ICE Connection State has changed: %s\n", connectionState.String())
})
// Send the current time via a DataChannel to the remote peer every 3 seconds
peerConnection.OnDataChannel(func(d *webrtc.DataChannel) {
d.OnOpen(func() {
for range time.Tick(time.Second * 3) {
if err = d.SendText(time.Now().String()); err != nil {
panic(err)
}
}
})
})
buf := make([]byte, 1500)
for {
// Read each inbound WebSocket Message
n, err := ws.Read(buf)
if err != nil {
panic(err)
}
// Unmarshal each inbound WebSocket message
var (
candidate webrtc.ICECandidateInit
offer webrtc.SessionDescription
)
switch {
// Attempt to unmarshal as a SessionDescription. If the SDP field is empty
// assume it is not one.
case json.Unmarshal(buf[:n], &offer) == nil && offer.SDP != "":
if err = peerConnection.SetRemoteDescription(offer); err != nil {
panic(err)
}
answer, answerErr := peerConnection.CreateAnswer(nil)
if answerErr != nil {
panic(answerErr)
}
if err = peerConnection.SetLocalDescription(answer); err != nil {
panic(err)
}
outbound, marshalErr := json.Marshal(answer)
if marshalErr != nil {
panic(marshalErr)
}
if _, err = ws.Write(outbound); err != nil {
panic(err)
}
// Attempt to unmarshal as a ICECandidateInit. If the candidate field is empty
// assume it is not one.
case json.Unmarshal(buf[:n], &candidate) == nil && candidate.Candidate != "":
if err = peerConnection.AddICECandidate(candidate); err != nil {
panic(err)
}
default:
panic("Unknown message")
}
}
}
func main() {
http.Handle("/", http.FileServer(http.Dir(".")))
http.Handle("/websocket", websocket.Handler(websocketServer))
fmt.Println("Open http://localhost:8080 to access this demo")
panic(http.ListenAndServe(":8080", nil))
}
|
