Gxl网相关教程推荐：Node.js视频教程
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 >
<p class="vertical-center">
<p class="container">
<p> </p>
<form role="form" id="chat_form" onsubmit="sendMessage(); return false;">
<p class="form-group">
<input class="form-control" type="text" name="message" id="message"
placeholder="Type text to echo in here" value="" />
</p>
<button type="button" id="send" class="btn btn-primary"
onclick="sendMessage();">
Send! </button>
</form>
</p>
</p></body></html>View Code
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。
<p class="vertical-center"> <p class="container"> <ul id="messages" class="list-unstyled"></ul> <hr/> <form role="form" id="chat_form" onsubmit="sendMessage(); return false;"> <p class="form-group"> <input class="form-control" type="text" id="message" name="message" placeholder="Type text to echo in here" value="" autofocus/> </p> <button type="button" id="send" class="btn btn-primary" onclick="sendMessage();"> Send Message </button> </form> <p class="form-group"><span>nikename：</span><input id="name" type="text" /> <button class="btn btn-sm btn-info" onclick="changName();">change</button></p> </p> </p>
View Code
js:
ws = WebSocket("ws://localhost:8181" nickname = ""= 'Connection to server opened'
( message == "undefined") messages = document.getElementById('messages' messageElem = document.createElement("li" (type === 'notification'= "<span class=\"label label-info\">*</span>" (type == 'nick_update'= "<span class=\"label label-warning\">*</span>"= "<span class=\"label label-success\">"
+ nickname + "</span>" message_text = "<h2>" + preface_label + " "
+ message + "</h2>"=
ws.onmessage = data =="ID: [%s] = %s"= "Connection closed""Connection closed"
messageField = document.getElementById('message' (ws.readyState ==== ''
name = $("#name" (ws.readyState ==="/nick " +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。
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