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
|
package webrtc
import (
"fmt"
"strings"
)
// ExampleGatheringCompletePromise demonstrates how to implement
// non-trickle ICE in Pion, an older form of ICE that does not require an
// asynchronous side channel between peers: negotiation is just a single
// offer-answer exchange. It works by explicitly waiting for all local
// ICE candidates to have been gathered before sending an offer to the peer.
func ExampleGatheringCompletePromise() {
// create a peer connection
pc, err := NewPeerConnection(Configuration{})
if err != nil {
panic(err)
}
defer func() {
closeErr := pc.Close()
if closeErr != nil {
panic(closeErr)
}
}()
// add at least one transceiver to the peer connection, or nothing
// interesting will happen. This could use pc.AddTrack instead.
_, err = pc.AddTransceiverFromKind(RTPCodecTypeVideo)
if err != nil {
panic(err)
}
// create a first offer that does not contain any local candidates
offer, err := pc.CreateOffer(nil)
if err != nil {
panic(err)
}
// gatherComplete is a channel that will be closed when
// the gathering of local candidates is complete.
gatherComplete := GatheringCompletePromise(pc)
// apply the offer
err = pc.SetLocalDescription(offer)
if err != nil {
panic(err)
}
// wait for gathering of local candidates to complete
<-gatherComplete
// compute the local offer again
offer2 := pc.LocalDescription()
// this second offer contains all candidates, and may be sent to
// the peer with no need for further communication. In this
// example, we simply check that it contains at least one
// candidate.
hasCandidate := strings.Contains(offer2.SDP, "\na=candidate:")
if hasCandidate {
fmt.Println("Ok!")
}
// Output: Ok!
}
|
