用nodejs搭建websocket服务器

2019-11-19 17:47:44

字体：大中小

来源：转载

供稿：网友

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。