JavaScript

超轻量级php框架startmvc

用nodejs搭建websocket服务器

更新时间:2020-04-21 00:29:50 作者:startmvc
 简单开始1.安装node。https://nodejs.org/en/ 2.安装ws模块ws:是nodejs的一个WebSocket库,可

 简单开始

1.安装node。https://nodejs.org/en/ 

2.安装ws模块

ws:是nodejs的一个WebSocket库,可以用来创建服务。 https://github.com/websockets/ws

3.server.js

在项目里面新建一个server.js,创建服务,指定8181端口,将收到的消息log出来。


var WebSocketServer = require('ws').Server,
wss = new WebSocketServer({ port: 8181 });
wss.on('connection', function (ws) {
 console.log('client connected');
 ws.on('message', function (message) {
 console.log(message);
 });
});

4.建立一个client.html。

在页面上建立一个WebSocket的连接。用send方法发送消息。


 var ws = new WebSocket("ws://localhost:8181");
 ws.onopen = function (e) {
 console.log('Connection to server opened');
 }
 function sendMessage() {
 ws.send($('#message').val());
 }

页面: 


<html xmlns="http://www.w3.org/1999/xhtml">
<head>
 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
 <title>WebSocket Echo Demo</title>
 <meta name="viewport" content="width=device-width, initial-scale=1"/>
 <link href="../bootstrap-3.3.5/css/bootstrap.min.css" rel="stylesheet" />
 <script src="../js/jquery-1.12.3.min.js"></script>
 <script src="../js/jquery-1.12.3.min.js"></script>
 <script src="../bootstrap-3.3.5/js/bootstrap.min.js"></script>
 <script>
 var ws = new WebSocket("ws://localhost:8181");
 ws.onopen = function (e) {
 console.log('Connection to server opened');
 }
 function sendMessage() {
 ws.send($('#message').val());
 }
 </script>
</head>

<body >
 <div class="vertical-center">
 <div class="container">
 <p> </p>
 <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="Type text to echo in here" value="" />
 </div>
 <button type="button" id="send" class="btn btn-primary"
 onclick="sendMessage();">
 Send!
 </button>
 </form>
 </div>
 </div>
</body>
</html>

运行之后如下,服务端即时获得客户端的消息。

模拟股票

上面的例子很简单,只是为了演示如何运用nodejs的ws创建一个WebSocket服务器。且可以接受客户端的消息。那么下面这个例子演示股票的实时更新。客服端只需要连接一次,服务器端会不断地发送新数据,客户端收数据后更新UI.页面如下,有五只股票,开始和停止按钮测试连接和关闭。

 服务端:

 1.模拟五只股票的涨跌。


var stocks = {
 "AAPL": 95.0,
 "MSFT": 50.0,
 "AMZN": 300.0,
 "GOOG": 550.0,
 "YHOO": 35.0
}
function randomInterval(min, max) {
 return Math.floor(Math.random() * (max - min + 1) + min);
}
var stockUpdater;
var randomStockUpdater = function() {
 for (var symbol in stocks) {
 if(stocks.hasOwnProperty(symbol)) {
 var randomizedChange = randomInterval(-150, 150);
 var floatChange = randomizedChange / 100;
 stocks[symbol] += floatChange;
 }
 }
 var randomMSTime = randomInterval(500, 2500);
 stockUpdater = setTimeout(function() {
 randomStockUpdater();
 }, randomMSTime);
}
randomStockUpdater();

2.连接建立之后就开始更新数据


wss.on('connection', function (ws) {
 var sendStockUpdates = function (ws) {
 if (ws.readyState == 1) {
 var stocksObj = {};
 for (var i = 0; i < clientStocks.length; i++) {
 var symbol = clientStocks[i];
 stocksObj[symbol] = stocks[symbol];
 }
 if (stocksObj.length !== 0) {
 ws.send(JSON.stringify(stocksObj));//需要将对象转成字符串。WebSocket只支持文本和二进制数据
 console.log("更新", JSON.stringify(stocksObj));
 }
 
 }
 }
 var clientStockUpdater = setInterval(function () {
 sendStockUpdates(ws);
 }, 1000);
 ws.on('message', function (message) {
 var stockRequest = JSON.parse(message);//根据请求过来的数据来更新。
 console.log("收到消息", stockRequest);
 clientStocks = stockRequest['stocks'];
 sendStockUpdates(ws);
 });

客户端:

建立连接:


 var ws = new WebSocket("ws://localhost:8181");

onopen直接只有在连接成功后才会触发,在这个时候将客户端需要请求的股票发送给服务端。


var isClose = false;
 var stocks = {
 "AAPL": 0, "MSFT": 0, "AMZN": 0, "GOOG": 0, "YHOO": 0
 };
 function updataUI() {
 ws.onopen = function (e) {
 console.log('Connection to server opened');
 isClose = false;
 ws.send(JSON.stringify(stock_request));
 console.log("sened a mesg");
 }
 //更新UI
 var changeStockEntry = function (symbol, originalValue, newValue) {
 var valElem = $('#' + symbol + ' span');
 valElem.html(newValue.toFixed(2));
 if (newValue < originalValue) {
 valElem.addClass('label-danger');
 valElem.removeClass('label-success');
 } else if (newValue > originalValue) {
 valElem.addClass('label-success');
 valElem.removeClass('label-danger');
 }
 }
 // 处理受到的消息
 ws.onmessage = function (e) {
 var stocksData = JSON.parse(e.data);
 console.log(stocksData);
 for (var symbol in stocksData) {
 if (stocksData.hasOwnProperty(symbol)) {
 changeStockEntry(symbol, stocks[symbol], stocksData[symbol]);
 stocks[symbol] = stocksData[symbol];
 }
 }
 };
 }

 updataUI();

运行效果如下:只需要请求一次,数据就会不断的更新,效果是不是很赞,不用轮询,也不用长连接那么麻烦了。文章末尾会附上所有源码。

(美股的涨跌和A股的颜色是反的,即红跌绿涨)

实时聊天

上面的例子是连接建立之后,服务端不断给客户端发送数据。接下来例子是一个简单的聊天室类的例子。可以建立多个连接。

1.安装node-uuid模块,用来给每个连接一个唯一号。

2.服务端消息发送

消息类型分notification和message两种,前者是提示信息,后者是聊天内容。消息还包含一个id、昵称和消息内容。在上一节有学习到readyState有四个值,OPEN表示连接建立可以发送消息。如果页面关闭了,为WebSocket.CLOSE。


function wsSend(type, client_uuid, nickname, message) {
 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
 }));
 }
 }
}

3.服务端处理连接

每新增加一个连接,都会发送一条匿名用户的加入的提示消息,如果消息中带有“/nick” 认为这一个修改昵称的消息。然后更新客户端的昵称。其他都会当做聊天消息处理。


wss.on('connection', function(ws) {
 var client_uuid = uuid.v4();
 var nickname = "AnonymousUser" + clientIndex;
 clientIndex += 1;
 clients.push({ "id": client_uuid, "ws": ws, "nickname": nickname });
 console.log('client [%s] connected', client_uuid);
 var connect_message = nickname + " has connected";
 wsSend("notification", client_uuid, nickname, connect_message);
 console.log('client [%s] connected', client_uuid);
 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 = "Client " + old_nickname + " changed to " + nickname;
 wsSend("nick_update", client_uuid, nickname, nickname_message);
 }
 } else {
 wsSend("message", client_uuid, nickname, message);
 }
 });

处理连接关闭:


 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 + " has disconnected";
 }
 wsSend("notification", client_uuid, nickname, disconnect_message);
 clients.splice(i, 1);
 }
 }
 };
 ws.on('close', function () {
 closeSocket();
 });

4.客户端

 没有启动时,页面如下,change按钮用来修改昵称。


<div class="vertical-center">
 <div class="container">
 <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" id="message" name="message"
 placeholder="Type text to echo in here" value="" autofocus/>
 </div>
 <button type="button" id="send" class="btn btn-primary"
 onclick="sendMessage();">
 Send Message
 </button>

 </form>
 <div class="form-group"><span>nikename:</span><input id="name" type="text" /> <button class="btn btn-sm btn-info" onclick="changName();">change</button></div>
 </div>
 </div>

js:


 //建立连接
 var ws = new WebSocket("ws://localhost:8181");
 var nickname = "";
 ws.onopen = function (e) {
 console.log('Connection to server opened');
 }
 //显示
 function appendLog(type, nickname, message) {
 if (typeof message == "undefined") return;
 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);
 }
 //收到消息处理
 ws.onmessage = function (e) {
 var data = JSON.parse(e.data);
 nickname = data.nickname;
 appendLog(data.type, data.nickname, data.message);
 console.log("ID: [%s] = %s", data.id, data.message);
 }
 ws.onclose = function (e) {
 appendLog("Connection closed");
 console.log("Connection closed");
 }
 //发送消息
 function sendMessage() {
 var messageField = document.getElementById('message');
 if (ws.readyState === WebSocket.OPEN) {
 ws.send(messageField.value);
 }
 messageField.value = '';
 messageField.focus();
 }
 //修改名称
 function changName() {
 var name = $("#name").val();
 if (ws.readyState === WebSocket.OPEN) {
 ws.send("/nick " + name);
 }
 }

 运行结果:

 页面关闭之后,连接马上断开。

 这种实时响应的体验简直不能太爽,代码也清爽了,前端体验也更好,客户端不用一直发请求,服务端不用等着被轮询。

 小结:上面例子的代码都很好理解,接下来学习WebSocket协议。

demo下载:http://xiazai.jb51.net/201701/yuanma/websocket_jb51.rar

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。