webSocket

首先安装node。

然后

npm install ws

ws是webSocket模块。

然后创建一个sever.js文件，在里面新建一个服务

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);
    });
});

之后就是页面了，index.html，在页面中创建一个连接

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

使用send方法发送数据。

一个实时聊天的例子                                                                                    

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。

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 + "&nbsp;&nbsp;"
            + 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);
            }
        }

 源码：http://pan.baidu.com/s/1c2FfKbA

 源码：http://pan.baidu.com/s/1o8KRmUQ  加入了socket.io的实现。

 API：WebSocket API

 相关：websoket使用Protocol Buffers3.0传输