【总目录】

【实例简介】

本文，我们通过nodejs和javascript实现一个网页聊天室的demo。主要包括，聊天，改用户名，查看其他用户在线状态的功能。大致流程为，用户访问网页，即进入聊天状态，成为新游客，通过底部的输入框，可以输入自己想说的话，点击发布，信息呈现给所有在聊天的人的页面。用户可以实时修改自己的昵称，用户离线上线都会实时广播给其他用户！

【效果图】

【客户端】

web页面主要呈现在线人数，聊天信息，一个输入框和发送按钮，上代码:

[html] view plain copy

<!DOCTYPE html>
<html lang="cn">
<head>
<title>WebSocket chart application</title>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<link rel="stylesheet" href="http://cdn.bootcss.com/bootstrap/4.0.0-alpha.2/css/bootstrap.css">
<link rel="stylesheet" href="http://cdn.bootcss.com/tether/1.3.2/css/tether.css"/>
<script src="http://cdn.bootcss.com/jquery/2.2.4/jquery.js" ></script>
<script src="http://cdn.bootcss.com/tether/1.3.2/js/tether.js"></script>
<script src="http://cdn.bootcss.com/bootstrap/4.0.0-alpha.2/js/bootstrap.js"></script>
<script>
var ws= new WebSocket('ws://www.liumumu.top:8180');
var nickname;
ws.onopen = function(e){
console.log('Connection to server opened');
}
function appendLog(type,nickname, message,clientcount) {
var messages = document.getElementById('messages');
var messageElem = document.createElement("li");
var preface_label;
if(type==='notification') {
preface_label = "<span class="label label-info">*</span>";
} else if(type==='nick_update') {
preface_label = "<span class="label label-warning">*</span>";
} else {
preface_label = "<span class="label label-success">" + nickname + "</span>";
}
var message_text = "<h2>" + preface_label + " " + message + "</h2>";
messageElem.innerHTML = message_text;
messages.appendChild(messageElem);
var count_people = document.getElementById("count_people");
count_people.innerHTML = clientcount;
}
ws.onmessage = function(e){
var data = JSON.parse(e.data);
nickname = data.nickname;
appendLog(data.type,data.nickname, data.message,data.clientcount);
console.log("ID: [%s] = %s", data.id, data.message);
}
function sendMessage(){
var message = $('#message').val().trim();
if(message.length<1){
alert("不能发送空内容！");
return;
}
ws.send($('#message').val());
$('#message').val("");
$('#message').focus();
console.log(ws.bufferedAmount);
}
</script>
</head>
<body lang="cn">
<div class="vertical-center">
<div class="container">
<h2>多人在线聊天DEMO</h2>
<hr />
<p>当前在线人数：<span id="count_people">0</span></p>
<ul id="messages" class="list-unstyled">
</ul>
<hr />
<form role="form" id="chat_form" onsubmit="sendMessage(); return false;">
<div class="form-group">
<input class="form-control" type="text" name="message" id="message"
placeholder="输入聊天内容" value="" autofocus/>
</div>
<button type="button" id="send" class="btn btn-primary"
onclick="sendMessage();">发送!</button>
</form>
</div>
</div>
</body>
</html>

javascript 部分，连接websocket成功之后，主要是监听数据返回，和发送数据。

当用户编辑好内容，点击发送按钮是调用sendMessage方法，发送数据，如果需要修改昵称，则发送数据格式为"/nick 昵称"。

当服务器返回数据到客户端，我们通过appendLog方法对数据做处理，根据type字段，判断是显示用户离线在线信息，还是显示聊天信息。最后更新在线人数。

【服务器端】

服务器端主要是接收信息，判断是聊天信息还是重命名信息，然后发送广播。同时，当用户连接上服务器端或者关闭连接时，服务器也会发送广播通知其他用户。

[javascript] view plain copy

var WebSocket = require('ws');
var WebSocketServer = WebSocket.Server,
wss = new WebSocketServer({port: 8180});
var uuid = require('node-uuid');
var clients = [];
function wsSend(type, client_uuid, nickname, message,clientcount) {
for(var i=0; i<clients.length; i++) {
var clientSocket = clients[i].ws;
if(clientSocket.readyState === WebSocket.OPEN) {
clientSocket.send(JSON.stringify({
"type": type,
"id": client_uuid,
"nickname": nickname,
"message": message,
"clientcount":clientcount,
}));
}
}
}
var clientIndex = 1;
wss.on('connection', function(ws) {
var client_uuid = uuid.v4();
var nickname = "游客"+clientIndex;
clientIndex+=1;
clients.push({"id": client_uuid, "ws": ws, "nickname": nickname});
console.log('client [%s] connected', client_uuid);
var connect_message = nickname + " 来了";
wsSend("notification", client_uuid, nickname, connect_message,clients.length);
ws.on('message', function(message) {
if(message.indexOf('/nick') === 0) {
var nickname_array = message.split(' ');
if(nickname_array.length >= 2) {
var old_nickname = nickname;
nickname = nickname_array[1];
var nickname_message = "用户 " + old_nickname + " 改名为： " + nickname;
wsSend("nick_update", client_uuid, nickname, nickname_message,clients.length);
}
} else {
wsSend("message", client_uuid, nickname, message,clients.length);
}
});
var closeSocket = function(customMessage) {
for(var i=0; i<clients.length; i++) {
if(clients[i].id == client_uuid) {
var disconnect_message;
if(customMessage) {
disconnect_message = customMessage;
} else {
disconnect_message = nickname + " 走了";
}
clients.splice(i, 1);
wsSend("notification", client_uuid, nickname, disconnect_message,clients.length);
}
}
}
ws.on('close', function() {
closeSocket();
});
process.on('SIGINT', function() {
console.log("Closing things");
closeSocket('Server has disconnected');
process.exit();
});
});

我们定义了wsSend函数用来处理消息的广播。对每个连接的用户，我们默认给他分配为游客。为了实现广播，我们用clients数组来保存连接的用户。