Release [email protected]

Breaking Changes

Trickle ICE is now enabled by default

Before /v3 Pion WebRTC would gather all candidates before a CreateOffer or CreateAnswer generated a SDP. This would cause a few issues in real world applications. You can read about the benefits of Trickle ICE here

• Longer call connection times since we blocked for STUN/TURN even if not needed
• This didn't comply with the WebRTC spec
• Made it harder for users to filter/process ICE Candidates

Now you should exchange ICE Candidates that are pushed via the OnICECandidate callback.

Before

  peerConnection, _ := webrtc.NewPeerConnection(webrtc.Configuration{})

  offer, _ := peerConnection.CreateOffer()
  peerConnection.SetLocalDescription(offer)

  // Send `offer` to remote peer
  websocket.Write(offer)

After

  peerConnection, _ := webrtc.NewPeerConnection(webrtc.Configuration{})

  // Set ICE Candidate handler. As soon as a PeerConnection has gathered a candidate
  // send it to the other peer
  peerConnection.OnICECandidate(func(i *webrtc.ICECandidate) {
    // Send ICE Candidate via Websocket/HTTP/$X to remote peer
  })

  // Listen for ICE Candidates from the remote peer
  peerConnection.AddICECandidate(remoteCandidate)

  // You still signal like before, but `CreateOffer` will be much faster
  offer, _ := peerConnection.CreateOffer()
  peerConnection.SetLocalDescription(offer)

  // Send `offer` to remote peer
  websocket.Write(offer)

If you are unable to migrate we have provided a helper function to simulate the pre-v3 behavior.

Helper function to simulate non-trickle ICE

  peerConnection, _ := webrtc.NewPeerConnection(webrtc.Configuration{})

  offer, _ := peerConnection.CreateOffer()

  // Create channel that is blocked until ICE Gathering is complete
  gatherComplete := webrtc.GatheringCompletePromise(peerConnection)
  peerConnection.SetLocalDescription(offer)
  <-gatherComplete

  // Send `LocalDescription` to remote peer
  // This is the offer but populated with all the ICE Candidates
  websocket.Write(*peerConnection.LocalDescription())

This was changed with bb3aa9

A data channel is no longer implicitly created with a PeerConnection

Before /v3 Pion WebRTC would always insert a application Media Section. This means that an offer would work even if you didn't create a DataChannel or Transceiver, in /v3 you MUST create a DataChannel or track first. To better illustrate these are two SDPs, each from a different version of Pion WebRTC

/v2 SDP with no CreateDataChannel

v=0
o=- 8334017457074456852 1596089329 IN IP4 0.0.0.0
s=-
t=0 0
a=fingerprint:sha-256 91:B0:3A:6E:9E:43:9A:9D:1B:71:17:7D:FB:D0:5C:81:12:6E:61:D5:6C:BF:92:E8:8D:04:F5:92:EF:62:36:C9
a=group:BUNDLE 0
m=application 9 DTLS/SCTP 5000
c=IN IP4 0.0.0.0
a=setup:actpass
a=mid:0
a=sendrecv
a=sctpmap:5000 webrtc-datachannel 1024
a=ice-ufrag:yBlrlyMmuDdCfawp
a=ice-pwd:RzlouYCNYDNpPLJLdddFtUkMVpKVLYWz
a=candidate:foundation 1 udp 2130706431 192.168.1.8 51147 typ host generation 0
a=candidate:foundation 2 udp 2130706431 192.168.1.8 51147 typ host generation 0
a=end-of-candidates

/v3 SDP with no CreateDataChannel

v=0
o=- 8628031010413059766 1596089396 IN IP4 0.0.0.0
s=-
t=0 0
a=fingerprint:sha-256 64:79:7C:73:6B:8A:CF:34:9D:D0:9C:6B:31:07:44:0A:CD:56:F0:74:62:72:D4:23:D5:BC:B2:C9:46:55:C5:A3
a=group:BUNDLE

To simulate the old functionality, call CreateDataChannel after creating your PeerConnection and before calling anything else.

New Features

ICE Restarts

You can now initiate and accept an ICE Restart! This means that if a PeerConnection goes to Disconnected or Failed because of network interruption it is no longer fatal.

To use you just need to pass ICERestart: true in your OfferOptions. The answering PeerConnection will then restart also. This is supported in FireFox/Chrome and Mobile WebRTC Clients.

  peerConn, _ := NewPeerConnection(Configuration{})

  // PeerConnection goes to ICEConnectionStateFailed

  offer, _ := peerConn.CreateOffer(&OfferOptions{ICERestart: true})

This was implemented in f29414