javascript - WebRTC onicecandidate 永远不会在 Chrome 中触发

Question

我的 webrtc 网络应用程序从来没有出现过 onicecandidate。当我查看本地(Webrtc 对象)对象时，设置了本地描述和远程描述。在 Firefox 中，它会触发 onicecandidate 但 event.candidate 为 null

我花了几个小时尝试解决这个问题，但没有成功

谁能解决这个问题吗？

如何触发 onicecandidate 事件？

  let local = new RTCPeerConnection();
  let remote = new RTCPeerConnection();
  try {
    local.createOffer().then(function(sdp) {
      console.log("Offer Created by Local: " + sdp.sdp);
      local.setLocalDescription(sdp);
      remote.setRemoteDescription(sdp);

      remote.createAnswer().then(function(sdp){
        console.log("Answer Created by Remote: " + sdp.sdp);
        remote.setLocalDescription(sdp);
        local.setRemoteDescription(sdp);
        local.onicecandidate = localicecandidate;
        remote.onicecandidate = remoteicecandidate;

        let channel = local.createDataChannel("channel");
        channel.onopen = function(event) {
          console.log("Channel opened");
        }
        channel.onmessgae = function(event) {
          console.log(event.data);
        }

        remote.ondatachannel = function(event) {
          let channel = event.channel;
          channel.onopen = function(event) {
            channel.send("Hi!");
          }
        }

        function localicecandidate (event) {
          console.log("Local got new Ice Candidate: " + event.candidate);
          remote.addIceCandidate(new RTCIceCandidate(event.candidate));
        }
        function remoteicecandidate (event) {
          console.log("Remote got new Ice Candidate: " + event);
          local.addIceCandidate(new RTCIceCandidate(event.candidate));
        }

      }); 
    })
  }

  catch (e) {
    console.log("Got Error" + e);
  }

Answer 1

在调用createOffer之前您没有调用createDataChannel，因此您的SDP不包含m=lines。如果没有 m 线，ICE 就没有任何谈判余地。

将 let channel = local.createDataChannel("channel"); 移至 createOffer 之前。