EDIT: 我写了一篇详细的教程，说明如何构建一个包括标志服务器在内的简单视频聊天应用程序:
教程：使用HTML和JavaScript创建自己的视频聊天应用程序
如果您觉得有帮助并且易于理解，请告诉我。谢谢！
我正在尝试通过WebRTC和Websocket（nodejs-server）使流程工作。据我所见，通过SDP握手协议工作，Peerconnection已经建立。
问题是——远程视频无法播放。src属性获取Blob，autoplay被设置，但它就是不会播放。可能我在ICE-candidates方面做错了什么（它们用于媒体流传输，对吗？）。
是否有任何方法检查PeerConnection是否正确设置？
编辑：也许我应该解释一下代码如何工作：
在网站加载时，与websocket服务器建立连接，并创建一个使用Google的STUN服务器的PeerConnection，然后收集和添加视频和音频流到PeerConnection中
当一个用户点击“创建提议”按钮时，将包含其会话描述（SDP）的消息发送到服务器（客户端函数sendOffer()），服务器广播该消息到另一个用户
其他用户接收到消息并保存他收到的SDP。
如果用户点击“接受提议”，则将SDP添加到RemoteDescription（func createAnswer()）中，然后将包含回答方SDP的应答消息发送给提出提议的用户。
在提议者的一侧，执行offerAccepted()函数，将另一个用户的SDP添加到其RemoteDesription中。
我不确定icecandidate处理程序是在哪个点被调用的，但我认为它们应该能工作，因为我在两侧都得到了日志。
这是我的代码（仅用于测试，所以即使有一个名为broadcast的函数，也只有两个用户可以同时进入同一个网站）：
index.html的标记：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<style>
#acceptOffer {
display: none;
}
</style>
</head>
<body>
<h2>Chat</h2>
<div>
<textarea class="output" name="" id="" cols="30" rows="10"></textarea>
</div>
<button id="createOffer">create Offer</button>
<button id="acceptOffer">accept Offer</button>
<h2>My Stream</h2>
<video id="myStream" autoplay src=""></video>
<h2>Remote Stream</h2>
<video id="remoteStream" autoplay src=""></video>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.9.1/jquery.min.js"></script>
<script src="websocketClient.js"></script>
</body>
</html>
这里是服务器端代码：
"use strict";
var webSocketsServerPort = 61122;
var webSocketServer = require('websocket').server,
http = require('http'),
clients = [];
var server = http.createServer(function(request, response) {
// Not important for us. We're writing WebSocket server, not HTTP server
});
server.listen(webSocketsServerPort, function() {
console.log((new Date()) + " Server is listening on port " + webSocketsServerPort);
});
var wsServer = new webSocketServer({
httpServer: server
});
wsServer.on('request', function(request) {
console.log((new Date()) + ' Connection from origin ' + request.origin + '.');
var connection = request.accept(null, request.origin),
index = clients.push(connection) - 1,
userName=false;
console.log((new Date()) + ' Connection accepted from '+connection.remoteAddress);
// user sent some message
connection.on('message', function(message) {
var json = JSON.parse(message.utf8Data);
console.log(json.type);
switch (json.type) {
case 'broadcast':
broadcast(json);
break;
case 'emit':
emit({type:'offer', data:json.data.data});
break;
case 'client':
respondToClient(json, clients[index]);
break;
default:
respondToClient({type:'error', data:'Sorry, i dont understand that.'}, clients[index]);
break;
}
});
connection.on('close', function(connection) {
clients.splice(index,1);
console.log((new Date()) + " Peer " + connection.remoteAddress + " disconnected.");
broadcast({type:'text', data: userName+' has left the channel.'});
});
var respondToClient = function(data, client){
client.sendUTF(JSON.stringify( data ));
};
var broadcast = function(data){
for(var i = 0; i < clients.length; i++ ) {
if(i != index ) {
clients[i].sendUTF(JSON.stringify( data ));
}
}
};
var emit = function(){
// TBD
};
});
以下是客户端代码：
$(function () {
"use strict";
/**
* Websocket Stuff
**/
window.WebSocket = window.WebSocket || window.MozWebSocket;
// open connection
var connection = new WebSocket('ws://url-to-node-server:61122'),
myName = false,
mySDP = false,
otherSDP = false;
connection.onopen = function () {
console.log("connection to WebSocketServer successfull");
};
connection.onerror = function (error) {
console.log("WebSocket connection error");
};
connection.onmessage = function (message) {
try {
var json = JSON.parse(message.data),
output = document.getElementsByClassName('output')[0];
switch(json.callback) {
case 'offer':
otherSDP = json.data;
document.getElementById('acceptOffer').style.display = 'block';
break;
case 'setIceCandidate':
console.log('ICE CANDITATE ADDED');
peerConnection.addIceCandidate(json.data);
break;
case 'text':
var text = output.value;
output.value = json.data+'\n'+output.value;
break;
case 'answer':
otherSDP = json.data;
offerAccepted();
break;
}
} catch (e) {
console.log('This doesn\'t look like a valid JSON or something else went wrong.');
return;
}
};
/**
* P2P Stuff
**/
navigator.getMedia = ( navigator.getUserMedia ||
navigator.webkitGetUserMedia ||
navigator.mozGetUserMedia ||
navigator.msGetUserMedia);
// create Connection
var peerConnection = new webkitRTCPeerConnection(
{ "iceServers": [{ "url": "stun:stun.l.google.com:19302" }] }
);
var remoteVideo = document.getElementById('remoteStream'),
myVideo = document.getElementById('myStream'),
// get local video-Stream and add to Peerconnection
stream = navigator.webkitGetUserMedia({ audio: false, video: true }, function (stream) {
myVideo.src = webkitURL.createObjectURL(stream);
console.log(stream);
peerConnection.addStream(stream);
});
// executes if other side adds stream
peerConnection.onaddstream = function(e){
console.log("stream added");
if (!e)
{
return;
}
remoteVideo.setAttribute("src",URL.createObjectURL(e.stream));
console.log(e.stream);
};
// executes if my icecandidate is received, then send it to other side
peerConnection.onicecandidate = function(candidate){
console.log('ICE CANDITATE RECEIVED');
var json = JSON.stringify( { type: 'broadcast', callback:'setIceCandidate', data:candidate});
connection.send(json);
};
// send offer via Websocket
var sendOffer = function(){
peerConnection.createOffer(function (sessionDescription) {
peerConnection.setLocalDescription(sessionDescription);
// POST-Offer-SDP-For-Other-Peer(sessionDescription.sdp, sessionDescription.type);
var json = JSON.stringify( { type: 'broadcast', callback:'offer',data:{sdp:sessionDescription.sdp,type:'offer'}});
connection.send(json);
}, null, { 'mandatory': { 'OfferToReceiveAudio': true, 'OfferToReceiveVideo': true } });
};
// executes if offer is received and has been accepted
var createAnswer = function(){
peerConnection.setRemoteDescription(new RTCSessionDescription(otherSDP));
peerConnection.createAnswer(function (sessionDescription) {
peerConnection.setLocalDescription(sessionDescription);
// POST-answer-SDP-back-to-Offerer(sessionDescription.sdp, sessionDescription.type);
var json = JSON.stringify( { type: 'broadcast', callback:'answer',data:{sdp:sessionDescription.sdp,type:'answer'}});
connection.send(json);
}, null, { 'mandatory': { 'OfferToReceiveAudio': true, 'OfferToReceiveVideo': true } });
};
// executes if other side accepted my offer
var offerAccepted = function(){
peerConnection.setRemoteDescription(new RTCSessionDescription(otherSDP));
console.log('it should work now');
};
$('#acceptOffer').on('click',function(){
createAnswer();
});
$('#createOffer').on('click',function(){
sendOffer();
});
});
我也看到了本地媒体流必须在发送任何offer之前收集。这是否意味着我必须在创建PeerConnection时添加它？例如：
// create Connection
var peerConnection = new webkitRTCPeerConnection(
{
"iceServers": [{ "url": "stun:stun.l.google.com:19302" }],
"mediaStream": stream // attach media stream here?
}
);
非常感谢，我非常欣赏任何帮助！
编辑2：我现在进展了一些。看起来由于“指定了无效或非法的字符串”，因此添加远程ice-candidates（客户端代码中的switch-case setIceCandidate）无法工作。json.data.candidate-object如下所示：
candidate: "a=candidate:1663431597 2 udp 1845501695 141.84.69.86 57538 typ srflx raddr 10.150.16.92 rport 57538 generation 0
↵"
sdpMLineIndex: 1
sdpMid: "video"
我尝试像这样创建一个新的候选人。
var remoteCandidate = new RTCIceCandidate(json.data.candidate);
peerConnection.addIceCandidate(remoteCandidate);
但是我仍然遇到了语法错误。