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WebRTC-文字演示

terry • • WebRTC教程 • 阅读 242

在本章中，我们将构建一个客户端应用程序，该客户端应用程序允许两个用户在不同的设备上使用WebRTC相互发送消息。我们的应用程序将有两页。一个用于登录，另一个用于向其他用户发送消息。

WebRTC-文字演示

这两个页面将是div标签。大多数输入是通过简单的事件处理程序完成的。

信令服务器

要创建WebRTC连接，客户端必须能够在不使用WebRTC对等连接的情况下传输消息。在这里我们将使用HTML5 WebSockets-两个端点之间的双向套接字连接-Web服务器和Web浏览器。现在让我们开始使用WebSocket库。创建server.js文件并插入以下代码：

//require our websocket library 
var WebSocketServer = require('ws').Server; 

//creating a websocket server at port 9090 
var wss = new WebSocketServer({port: 9090});
  
//when a user connects to our sever 
wss.on('connection', function(connection) { 
   console.log("user connected"); 
	
   //when server gets a message from a connected user 
   connection.on('message', function(message) { 
      console.log("Got message from a user:", message); 
   }); 
	
   connection.send("Hello from server"); 
});

第一行需要我们已经安装的WebSocket库。然后，我们在端口9090上创建一个套接字服务器。接下来，我们监听连接事件。当用户与服务器建立WebSocket连接时，将执行此代码。然后，我们收听用户发送的任何消息。最后，我们向连接的用户发送回复，说“来自服务器的问候”。

在信令服务器中，我们将为每个连接使用基于字符串的用户名，以便我们知道将消息发送到哪里。让我们稍微改变一下连接处理程序：

connection.on('message', function(message) { 
   var data; 
	
   //accepting only JSON messages 
   try { 
      data = JSON.parse(message); 
   } catch (e) { 
      console.log("Invalid JSON");
      data = {}; 
   } 
});

这样，我们仅接受JSON消息。接下来，我们需要将所有连接的用户存储在某个地方。我们将使用一个简单的Javascript对象。更改文件的顶部：

//require our websocket library 
var WebSocketServer = require('ws').Server; 

//creating a websocket server at port 9090 
var wss = new WebSocketServer({port: 9090}); 

//all connected to the server users 
var users = {};

我们将为来自客户端的每条消息添加一个类型字段。例如，如果用户要登录，则他发送登录类型消息。让我们定义它：

connection.on('message', function(message) { 
   var data; 
	
   //accepting only JSON messages 
   try { 
      data = JSON.parse(message); 
   } catch (e) { 
      console.log("Invalid JSON"); 
      data = {}; 
   }
	
   //switching type of the user message 
   switch (data.type) { 
      //when a user tries to login 
      case "login": 
         console.log("User logged:", data.name); 
			
         //if anyone is logged in with this username then refuse 
         if(users[data.name]) { 
            sendTo(connection, { 
               type: "login", 
               success: false
            }); 
         } else { 
            //save user connection on the server 
            users[data.name] = connection; 
            connection.name = data.name; 
				
            sendTo(connection, { 
               type: "login", 
               success: true 
            }); 
         } 
			
         break;
			
      default: 
         sendTo(connection, { 
            type: "error", 
            message: "Command no found: " + data.type 
         }); 
			
         break;
   } 
});

如果用户使用登录类型发送消息：

  • 检查是否有人已经使用该用户名登录。
  • 如果是这样，则告诉用户他尚未成功登录。
  • 如果没有人使用此用户名，则将用户名添加为连接对象的键。
  • 如果无法识别命令，我们将发送错误。

以下代码是用于将消息发送到连接的帮助程序功能。将其添加到server.js文件：

function sendTo(connection, message) { 
   connection.send(JSON.stringify(message)); 
}

当用户断开连接时，我们应该清理其连接。当关闭事件触发时，我们可以删除用户。将以下代码添加到连接处理程序：

connection.on("close", function() { 
   if(connection.name) { 
      delete users[connection.name]; 
   } 
});

成功登录后，用户要呼叫另一个。他应该向其他用户提出要约。添加报价处理程序：

case "offer": 
   //for ex. UserA wants to call UserB 
   console.log("Sending offer to: ", data.name); 
	
   //if UserB exists then send him offer details 
   var conn = users[data.name]; 
	
   if(conn != null){ 
   //setting that UserA connected with UserB 
   connection.otherName = data.name; 
	
      sendTo(conn, { 
         type: "offer", 
         offer: data.offer, 
         name: connection.name 
      }); 
     
   break;

首先，我们获得了要呼叫的用户的连接。如果存在，我们会向他发送报价详细信息。我们还将otherName添加到连接对象。这样做是为了以后找到它的简单性。

对响应进行回答的方式与要约处理程序中使用的方式类似。我们的服务器刚刚通过的所有消息的答案给其他用户。添加后，下面的代码提供处理程序：

case "answer": 
   console.log("Sending answer to: ", data.name); 
	
   //for ex. UserB answers UserA 
   var conn = users[data.name]; 
	
   if(conn != null) { 
      connection.otherName = data.name;
      sendTo(conn, { 
         type: "answer", 
         answer: data.answer 
      }); 
   } 
	
   break;

最后一部分是处理用户之间的ICE候选者。我们使用相同的技术只是在用户之间传递消息。主要区别在于候选消息可能以任意顺序在每个用户身上多次出现。添加候选处理程序：

case "candidate": 
   console.log("Sending candidate to:",data.name); 
   var conn = users[data.name];
	
   if(conn != null) { 
      sendTo(conn, { 
         type: "candidate", 
         candidate: data.candidate 
      }); 
   } 
	
   break;

为了允许我们的用户与另一个用户断开连接，我们应该实现挂断功能。它还将告诉服务器删除所有用户引用。添加请假处理程序：

case "leave": 
   console.log("Disconnecting from", data.name); 
   var conn = users[data.name]; 
   conn.otherName = null;
	
   //notify the other user so he can disconnect his peer connection 
   if(conn != null) { 
      sendTo(conn, { 
         type: "leave" 
      }); 
   }
	
   break;

这还将向其他用户发送请假事件，以便他可以相应地断开其对等连接。当用户从信令服务器断开连接时，我们也应该处理这种情况。让我们修改关闭处理程序：

connection.on("close", function() { 

   if(connection.name) { 
      delete users[connection.name]; 
		
      if(connection.otherName) { 
         console.log("Disconnecting from ", connection.otherName); 
         var conn = users[connection.otherName]; 
         conn.otherName = null;  
			
         if(conn != null) { 
            sendTo(conn, { 
               type: "leave" 
            }); 
         }  
      } 
   } 
});

以下是我们的信令服务器的完整代码：

//require our websocket library 
var WebSocketServer = require('ws').Server;
 
//creating a websocket server at port 9090 
var wss = new WebSocketServer({port: 9090}); 

//all connected to the server users 
var users = {};
  
//when a user connects to our sever 
wss.on('connection', function(connection) {
  
   console.log("User connected");
	 
   //when server gets a message from a connected user 
   connection.on('message', function(message) {
	 
      var data; 
      //accepting only JSON messages 
      try { 
         data = JSON.parse(message); 
      } catch (e) { 
         console.log("Invalid JSON"); 
         data = {}; 
      }
		  
      //switching type of the user message 
      switch (data.type) { 
         //when a user tries to login 
         case "login": 
            console.log("User logged", data.name); 
            //if anyone is logged in with this username then refuse 
            if(users[data.name]) { 
               sendTo(connection, { 
                  type: "login", 
                  success: false 
               }); 
            } else { 
               //save user connection on the server 
               users[data.name] = connection; 
               connection.name = data.name; 
					
               sendTo(connection, { 
                  type: "login", 
                  success: true 
               }); 
            }
				
            break;
				
         case "offer": 
            //for ex. UserA wants to call UserB 
            console.log("Sending offer to: ", data.name); 
				
            //if UserB exists then send him offer details 
            var conn = users[data.name]; 
				
            if(conn != null) { 
               //setting that UserA connected with UserB 
               connection.otherName = data.name; 
					
               sendTo(conn, { 
                  type: "offer", 
                  offer: data.offer, 
                  name: connection.name 
               }); 
            } 
				
            break;
				
         case "answer": 
            console.log("Sending answer to: ", data.name); 
            //for ex. UserB answers UserA 
            var conn = users[data.name]; 
				
            if(conn != null) { 
               connection.otherName = data.name; 
               sendTo(conn, { 
                  type: "answer", 
                  answer: data.answer 
               }); 
            } 
				
            break;
				
         case "candidate": 
            console.log("Sending candidate to:",data.name);
            var conn = users[data.name];  
				
            if(conn != null) { 
               sendTo(conn, { 
                  type: "candidate", 
                  candidate: data.candidate 
               }); 
            } 
				
            break;
				
         case "leave": 
            console.log("Disconnecting from", data.name); 
            var conn = users[data.name]; 
            conn.otherName = null; 
				
            //notify the other user so he can disconnect his peer connection 
            if(conn != null) { 
               sendTo(conn, { 
                  type: "leave"
               });
            }  
				
            break;
				
         default: 
            sendTo(connection, { 
               type: "error", 
               message: "Command not found: " + data.type 
            }); 
				
            break;
				
      }  
   });
	
   //when user exits, for example closes a browser window 
   //this may help if we are still in "offer","answer" or "candidate" state 
   connection.on("close", function() { 
	
      if(connection.name) { 
         delete users[connection.name]; 
			
         if(connection.otherName) { 
            console.log("Disconnecting from ", connection.otherName); 
            var conn = users[connection.otherName]; 
            conn.otherName = null;
				
            if(conn != null) { 
               sendTo(conn, { 
                  type: "leave" 
               }); 
            }  
         } 
      } 
   });
	
   connection.send("Hello world");
	
});
  
function sendTo(connection, message) { 
   connection.send(JSON.stringify(message)); 
}

客户申请

测试该应用程序的一种方法是打开两个浏览器选项卡，然后尝试互相发送消息。

首先，我们需要安装引导程序库。Bootstrap是用于开发Web应用程序的前端框架。您可以在http://getbootstrap.com/上了解更多信息。创建一个名为“ textchat”的文件夹。这将是我们的根应用程序文件夹。在此文件夹中创建一个文件package.json（管理npm依赖项是必需的）并添加以下内容：

{ 
   "name": "webrtc-textochat", 
   "version": "0.1.0", 
   "description": "webrtc-textchat", 
   "author": "Author", 
   "license": "BSD-2-Clause" 
}

然后运行npm install bootstrap。这会将引导程序库安装在textchat / node_modules文件夹中。

现在我们需要创建一个基本的HTML页面。使用以下代码在根文件夹中创建index.html文件：

<html> 

   <head> 
      <title>WebRTC Text Demo</title> 
      <link rel = "stylesheet" href = "node_modules/bootstrap/dist/css/bootstrap.min.css"/> 
   </head>
 
   <style> 
      body { 
         background: #eee; 
         padding: 5% 0; 
      } 
   </style>
	
   <body> 
      <div id = "loginPage" class = "container text-center"> 
		
         <div class = "row"> 
            <div class = "col-md-4 col-md-offset-4"> 
               <h2>WebRTC Text Demo. Please sign in</h2> 
               <label for = "usernameInput" class = "sr-only">Login</label> 
               <input type = "email" id = "usernameInput" 
                  class = "form-control formgroup" placeholder = "Login" 
                  required = "" autofocus = "">
               <button id = "loginBtn" class = "btn btn-lg btn-primary btnblock">
                  Sign in</button> 
            </div> 
         </div> 
			
      </div>
		
      <div id = "callPage" class = "call-page container">
		
         <div class = "row"> 
            <div class = "col-md-4 col-md-offset-4 text-center"> 
               <div class = "panel panel-primary"> 
                  <div class = "panel-heading">Text chat</div> 
                  <div id = "chatarea" class = "panel-body text-left"></div> 
               </div> 
            </div> 
         </div>
			
         <div class = "row text-center form-group"> 
            <div class = "col-md-12"> 
               <input id = "callToUsernameInput" type = "text" 
                  placeholder = "username to call" /> 
               <button id = "callBtn" class = "btn-success btn">Call</button> 
               <button id = "hangUpBtn" class = "btn-danger btn">Hang Up</button> 
            </div> 
         </div> 
			
         <div class = "row text-center"> 
            <div class = "col-md-12"> 
               <input id = "msgInput" type = "text" placeholder = "message" /> 
               <button id = "sendMsgBtn" class = "btn-success btn">Send</button> 
            </div> 
         </div>
			
      </div> 
		
      <script src = "client.js"></script> 
		
   </body>
 
</html>

您应该熟悉此页面。我们添加了引导css文件。我们还定义了两个页面。最后，我们创建了几个文本字段和按钮，用于从用户那里获取信息。在“聊天”页面上，您应该看到带有“ chatarea” ID的div标签，将在其中显示我们所有的消息。请注意，我们已经添加了指向client.js文件的链接。

现在我们需要与我们的信令服务器建立连接。使用以下代码在根文件夹中创建client.js文件：

//our username 
var name; 
var connectedUser;
  
//connecting to our signaling server 
var conn = new WebSocket('ws://localhost:9090');
  
conn.onopen = function () { 
   console.log("Connected to the signaling server"); 
}; 
 
//when we got a message from a signaling server 
conn.onmessage = function (msg) { 
   console.log("Got message", msg.data);
	
   var data = JSON.parse(msg.data);
	
   switch(data.type) { 
      case "login": 
         handleLogin(data.success); 
         break; 
      //when somebody wants to call us 
      case "offer": 
         handleOffer(data.offer, data.name); 
         break; 
      case "answer": 
         handleAnswer(data.answer); 
         break; 
      //when a remote peer sends an ice candidate to us 
      case "candidate":
         handleCandidate(data.candidate); 
         break; 
      case "leave": 
         handleLeave(); 
         break; 
      default: 
         break; 
   } 
};
  
conn.onerror = function (err) { 
   console.log("Got error", err); 
};
  
//alias for sending JSON encoded messages 
function send(message) { 
   //attach the other peer username to our messages 
   if (connectedUser) { 
      message.name = connectedUser; 
   } 
	
   conn.send(JSON.stringify(message)); 
};

现在通过节点服务器运行我们的信令服务器。然后，在根文件夹中运行static命令并在浏览器中打开页面。您应该看到以下控制台输出：

WebRTC-文字演示

下一步是使用唯一的用户名实现用户登录。我们只需将用户名发送到服务器，然后服务器告诉我们是否已使用该用户名。将以下代码添加到client.js文件中：

//****** 
//UI selectors block
//****** 

var loginPage = document.querySelector('#loginPage'); 
var usernameInput = document.querySelector('#usernameInput'); 
var loginBtn = document.querySelector('#loginBtn'); 

var callPage = document.querySelector('#callPage'); 
var callToUsernameInput = document.querySelector('#callToUsernameInput'); 
var callBtn = document.querySelector('#callBtn'); 

var hangUpBtn = document.querySelector('#hangUpBtn'); 
callPage.style.display = "none"; 

// Login when the user clicks the button 
loginBtn.addEventListener("click", function (event) { 
   name = usernameInput.value;
	
   if (name.length > 0) { 
      send({ 
         type: "login", 
         name: name 
      }); 
   } 
	
});
 
function handleLogin(success) { 

   if (success === false) { 
      alert("Ooops...try a different username"); 
   } else { 
      loginPage.style.display = "none"; 
      callPage.style.display = "block"; 
		
      //********************** 
      //Starting a peer connection 
      //********************** 
   } 
	
};

首先，我们选择一些对页面上元素的引用。我们隐藏了呼叫页面。然后，我们在登录按钮上添加一个事件侦听器。当用户单击它时，我们会将其用户名发送到服务器。最后，我们实现handleLogin回调。如果登录成功，我们将显示呼叫页面，建立对等连接并创建数据通道。

要开始与数据通道的对等连接，我们需要：

  • 创建RTCPeerConnection对象
  • 在我们的RTCPeerConnection对象中创建一个数据通道

将以下代码添加到“ UI选择器块”

var msgInput = document.querySelector('#msgInput'); 
var sendMsgBtn = document.querySelector('#sendMsgBtn'); 
var chatArea = document.querySelector('#chatarea'); 

var yourConn; 
var dataChannel;

修改handleLogin函数

function handleLogin(success) { 
   if (success === false) { 
      alert("Ooops...try a different username"); 
   } else { 
      loginPage.style.display = "none"; 
      callPage.style.display = "block";
		
      //********************** 
      //Starting a peer connection 
      //**********************
		
      //using Google public stun server 
      var configuration = { 
         "iceServers": [{ "url": "stun:stun2.1.google.com:19302" }] 
      }; 
		
      yourConn = new webkitRTCPeerConnection(configuration, {optional: [{RtpDataChannels: true}]});
		
      // Setup ice handling 
      yourConn.onicecandidate = function (event) { 
         if (event.candidate) { 
            send({
               type: "candidate", 
               candidate: event.candidate 
            }); 
         } 
      };
		
      //creating data channel 
      dataChannel = yourConn.createDataChannel("channel1", {reliable:true}); 
		
      dataChannel.onerror = function (error) { 
         console.log("Ooops...error:", error); 
      };
		
      //when we receive a message from the other peer, display it on the screen 
      dataChannel.onmessage = function (event) { 
         chatArea.innerHTML += connectedUser + ": " + event.data + "<br />"; 
      };
		
      dataChannel.onclose = function () { 
         console.log("data channel is closed"); 
      };  
   } 
};

如果登录成功，则应用程序将创建RTCPeerConnection对象并设置onicecandidate处理程序，该处理程序会将找到的所有icecandidates发送给另一个对等方。它还创建一个dataChannel。请注意，在创建RTCPeerConnection对象时，如果使用的是Chrome或Opera，则构造函数可选的第二个参数[{RtpDataChannels：true}]是必需的。下一步是向其他对等方创建要约。用户获得报价后，他将创建答案并开始交易ICE候选人。将以下代码添加到client.js文件

//initiating a call
callBtn.addEventListener("click", function () { 
   var callToUsername = callToUsernameInput.value;
	
   if (callToUsername.length > 0) {
	
      connectedUser = callToUsername;
		
      // create an offer 
      yourConn.createOffer(function (offer) { 
		
         send({ 
            type: "offer", 
            offer: offer 
         }); 
			
         yourConn.setLocalDescription(offer); 
			
      }, function (error) { 
         alert("Error when creating an offer"); 
      });  
   } 
});
  
//when somebody sends us an offer 
function handleOffer(offer, name) { 
   connectedUser = name; 
   yourConn.setRemoteDescription(new RTCSessionDescription(offer));
	
   //create an answer to an offer 
   yourConn.createAnswer(function (answer) { 
      yourConn.setLocalDescription(answer); 
		
      send({ 
         type: "answer", 
         answer: answer 
      }); 
		
   }, function (error) { 
      alert("Error when creating an answer"); 
   });
};
  
//when we got an answer from a remote user 
function handleAnswer(answer) { 
   yourConn.setRemoteDescription(new RTCSessionDescription(answer)); 
};
  
//when we got an ice candidate from a remote user 
function handleCandidate(candidate) { 
   yourConn.addIceCandidate(new RTCIceCandidate(candidate)); 
};

我们增加一个点击处理程序呼叫按钮，从而启动的报价。然后，我们实现onmessage处理程序期望的几个处理程序。它们将被异步处理，直到两个用户都建立了连接。

下一步是实现挂断功能。这将停止传输数据，并告诉其他用户关闭数据通道。添加以下代码：

//hang up 
hangUpBtn.addEventListener("click", function () { 
   send({ 
      type: "leave" 
   }); 
	
   handleLeave(); 
}); 
 
function handleLeave() { 
   connectedUser = null; 
   yourConn.close(); 
   yourConn.onicecandidate = null; 
};

当用户单击“挂断”按钮时-

  • 它将向其他用户发送“离开”消息。
  • 它将关闭RTCPeerConnection和数据通道。

最后一步是向另一个对等方发送消息。将“点击”处理程序添加到“发送消息”按钮中

//when user clicks the "send message" button 
sendMsgBtn.addEventListener("click", function (event) { 
   var val = msgInput.value; 
   chatArea.innerHTML += name + ": " + val + "<br />"; 
	
   //sending a message to a connected peer 
   dataChannel.send(val); 
   msgInput.value = ""; 
});

现在运行代码。您应该能够使用两个浏览器选项卡登录到服务器。然后，您可以通过单击“挂断”按钮来建立与其他用户的对等连接，并向他发送消息以及关闭数据通道。

WebRTC-文字演示

以下是整个client.js文件

//our username 
var name; 
var connectedUser; 

//connecting to our signaling server 
var conn = new WebSocket('ws://localhost:9090'); 

conn.onopen = function () { 
   console.log("Connected to the signaling server");
};
 
//when we got a message from a signaling server 
conn.onmessage = function (msg) { 
   console.log("Got message", msg.data); 
   var data = JSON.parse(msg.data); 
	
   switch(data.type) { 
      case "login": 
         handleLogin(data.success); 
         break; 
      //when somebody wants to call us 
      case "offer": 
         handleOffer(data.offer, data.name); 
         break; 
      case "answer": 
         handleAnswer(data.answer); 
         break; 
      //when a remote peer sends an ice candidate to us 
      case "candidate": 
         handleCandidate(data.candidate); 
         break; 
      case "leave": 
         handleLeave(); 
         break; 
      default: 
         break; 
   } 
}; 

conn.onerror = function (err) { 
   console.log("Got error", err); 
}; 

//alias for sending JSON encoded messages 
function send(message) { 

   //attach the other peer username to our messages
   if (connectedUser) { 
      message.name = connectedUser; 
   } 
	
   conn.send(JSON.stringify(message)); 
};
 
//****** 
//UI selectors block 
//****** 

var loginPage = document.querySelector('#loginPage'); 
var usernameInput = document.querySelector('#usernameInput'); 
var loginBtn = document.querySelector('#loginBtn'); 

var callPage = document.querySelector('#callPage'); 
var callToUsernameInput = document.querySelector('#callToUsernameInput');
var callBtn = document.querySelector('#callBtn'); 

var hangUpBtn = document.querySelector('#hangUpBtn'); 
var msgInput = document.querySelector('#msgInput'); 
var sendMsgBtn = document.querySelector('#sendMsgBtn'); 

var chatArea = document.querySelector('#chatarea'); 
var yourConn; 
var dataChannel; 
callPage.style.display = "none"; 

// Login when the user clicks the button 
loginBtn.addEventListener("click", function (event) { 
   name = usernameInput.value; 
	
   if (name.length > 0) { 
      send({ 
         type: "login", 
         name: name 
      }); 
   } 
	
});
 
function handleLogin(success) { 

   if (success === false) {
      alert("Ooops...try a different username"); 
   } else { 
      loginPage.style.display = "none"; 
      callPage.style.display = "block"; 
		
      //********************** 
      //Starting a peer connection 
      //********************** 
		
      //using Google public stun server 
      var configuration = { 
         "iceServers": [{ "url": "stun:stun2.1.google.com:19302" }] 
      }; 
		
      yourConn = new webkitRTCPeerConnection(configuration, {optional: [{RtpDataChannels: true}]}); 
		
      // Setup ice handling 
      yourConn.onicecandidate = function (event) { 
         if (event.candidate) { 
            send({ 
               type: "candidate", 
               candidate: event.candidate 
            }); 
         } 
      }; 
		
      //creating data channel 
      dataChannel = yourConn.createDataChannel("channel1", {reliable:true}); 
		
      dataChannel.onerror = function (error) { 
         console.log("Ooops...error:", error); 
      }; 
		
      //when we receive a message from the other peer, display it on the screen 
      dataChannel.onmessage = function (event) { 
         chatArea.innerHTML += connectedUser + ": " + event.data + "<br />"; 
      }; 
		
      dataChannel.onclose = function () { 
         console.log("data channel is closed"); 
      };
		
   } 
};
 
//initiating a call 
callBtn.addEventListener("click", function () { 
   var callToUsername = callToUsernameInput.value; 
	
   if (callToUsername.length > 0) { 
      connectedUser = callToUsername; 
      // create an offer 
      yourConn.createOffer(function (offer) { 
         send({ 
            type: "offer", 
            offer: offer 
         }); 
         yourConn.setLocalDescription(offer); 
      }, function (error) { 
         alert("Error when creating an offer"); 
      }); 
   } 
	
});
 
//when somebody sends us an offer 
function handleOffer(offer, name) { 
   connectedUser = name; 
   yourConn.setRemoteDescription(new RTCSessionDescription(offer)); 
	
   //create an answer to an offer 
   yourConn.createAnswer(function (answer) { 
      yourConn.setLocalDescription(answer); 
      send({ 
         type: "answer", 
         answer: answer 
      }); 
   }, function (error) { 
      alert("Error when creating an answer"); 
   });
	
};
 
//when we got an answer from a remote user 
function handleAnswer(answer) { 
   yourConn.setRemoteDescription(new RTCSessionDescription(answer)); 
};
 
//when we got an ice candidate from a remote user 
function handleCandidate(candidate) { 
   yourConn.addIceCandidate(new RTCIceCandidate(candidate)); 
};
 
//hang up 
hangUpBtn.addEventListener("click", function () { 
   send({ 
      type: "leave" 
   }); 
	
   handleLeave(); 
}); 

function handleLeave() { 
   connectedUser = null; 
   yourConn.close(); 
   yourConn.onicecandidate = null; 
};
 
//when user clicks the "send message" button 
sendMsgBtn.addEventListener("click", function (event) { 
   var val = msgInput.value; 
   chatArea.innerHTML += name + ": " + val + "<br />"; 
	
   //sending a message to a connected peer 
   dataChannel.send(val); 
   msgInput.value = ""; 
});

作者：terry，如若转载，请注明出处：https://www.web176.com/webrtc/712.html

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