RTCPeerConnection.canTrickleIceCandidates

読み取り専用の RTCPeerConnection プロパティ canTrickleIceCandidates は、リモート・ピアが trickled ICE 候補を受け入れることができるかどうかを示す Boolean を返します。

ICE トリックリングとは、最初のオファーや回答がすでに相手に送られた後も、候補者を送り続けるプロセスのことです。

This property is only set after having called RTCPeerConnection.setRemoteDescription() (en-US).  Ideally, your signaling protocol provides a way to detect trickling support, so that you don't need to rely on this property. A WebRTC browser will always support trickle ICE. If trickling isn't supported, or you aren't able to tell, you can check for a falsy value for this property and then wait until the value of iceGatheringState (en-US) changes to "completed" before creating and sending the initial offer. That way, the offer contains all of the candidates.

Syntax

 var canTrickle = RTCPeerConnection.canTrickleIceCandidates;

Value

A Boolean that is true if the remote peer can accept trickled ICE candidates and false if it cannot. If no remote peer has been established, this value is null.

Note: This property's value is determined once the local peer has called RTCPeerConnection.setRemoteDescription() (en-US); the provided description is used by the ICE agent to determine whether or not the remote peer supports trickled ICE candidates.

Example

var pc = new RTCPeerConnection();
// The following code might be used to handle an offer from a peer when
// it isn't known whether it supports trickle ICE.
pc.setRemoteDescription(remoteOffer)
  .then(_ => pc.createAnswer())
  .then(answer => pc.setLocalDescription(answer))
  .then(_ =>
    if (pc.canTrickleIceCandidates) {
      return pc.localDescription;
    }
    return new Promise(r => {
      pc.addEventListener('icegatheringstatechange', e => {
        if (e.target.iceGatheringState === 'complete') {
          r(pc.localDescription);
        }
      });
    });
  })
  .then(answer => sendAnswerToPeer(answer)) // signaling message
  .catch(e => handleError(e));

pc.addEventListener('icecandidate', e => {
  if (pc.canTrickleIceCandidates) {
    sendCandidateToPeer(e.candidate); // signaling message
  }
});

Specifications

Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
RTCPeerConnection.canTrickleIceCandidates の定義
勧告候補 Initial specification.

Browser compatibility

BCD tables only load in the browser

See also