javascript - RTCDataChannel 的 ReadyState 不是 'open'

Question

我正在尝试使用 WebRTC's adapter.js 通过 RTCPeerConnection 和 RTCDataChannel 发送文本，但出现以下错误:

Uncaught InvalidStateError:
Failed to execute 'send' on 'RTCDataChannel':
RTCDataChannel.readyState is not 'open'

我的代码可以通过 this fiddle 获得及以下:

var peerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

peerConnection.ondatachannel = function(event) {
  receiveChannel = event.channel;
  receiveChannel.onmessage = function(event){
    alert(event.data);
  };
};

var dataChannel = peerConnection.createDataChannel("data", {reliable: false});
dataChannel.send("Hello");

我做错了什么吗？

Answer 1

我今天早上写了下面的代码，在一个页面中使用了 RTCPeerConnection 和 RTCDataChannel。声明这些函数的顺序很重要。

var localPeerConnection, remotePeerConnection, sendChannel, receiveChannel;

localPeerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

localPeerConnection.onicecandidate = function(event) {
  if (event.candidate) {
    remotePeerConnection.addIceCandidate(event.candidate);
  }
};

sendChannel = localPeerConnection.createDataChannel("CHANNEL_NAME", {
  reliable: false
});

sendChannel.onopen = function(event) {
  var readyState = sendChannel.readyState;
  if (readyState == "open") {
    sendChannel.send("Hello");
  }
};

remotePeerConnection = new RTCPeerConnection(null, {
  optional: [{
    RtpDataChannels: true
  }]
});

remotePeerConnection.onicecandidate = function(event) {
  if (event.candidate) {
    localPeerConnection.addIceCandidate(event.candidate);
  }
};

remotePeerConnection.ondatachannel = function(event) {
  receiveChannel = event.channel;
  receiveChannel.onmessage = function(event) {
    alert(event.data);
  };
};

localPeerConnection.createOffer(function(desc) {
  localPeerConnection.setLocalDescription(desc);
  remotePeerConnection.setRemoteDescription(desc);
  remotePeerConnection.createAnswer(function(desc) {
    remotePeerConnection.setLocalDescription(desc);
    localPeerConnection.setRemoteDescription(desc);
  });
});