HTML5 Web socket和socket.io
what is websockets
Two-way communication over ont TCP socket, a type of PUSH technology
HTML5的新特性,用于双向推送消息(例如网页聊天,手机推送消息等)
原理:
- client利用regular http请求webpage
- 请求的webpage 执行javascript脚本,open a connection to server.
-
有新的信息时服务器和客户端可以相互发送信息(Real-time traffic from the server to the client and from the client to the server
客户端
说明:
readyState:
CONNECTING (0):表示还没建立连接;
OPEN (1): 已经建立连接,可以进行通讯;
CLOSING (2):通过关闭握手,正在关闭连接;
CLOSED (3):连接已经关闭或无法打开;
url: WebSocket 服务器的网络地址,协议通常是”ws”或“wss(加密通信)”,
事件:
- send:向服务器端发送数据
- close 方法就是关闭连接;
- onopen连接建立,即握手成功触发的事件;
- onmessage收到服务器消息时触发的事件;
- onerror异常触发的事件;
使用例子:
// 创建一个Socket实例 var socket = new WebSocket('ws://localhost:8080'); // 打开Socket socket.onopen = function(event) { // 发送一个初始化消息 socket.send('I am the client and I\'m listening!'); // 监听消息 socket.onmessage = function(event) { console.log('Client received a message',event); }; // 监听Socket的关闭 socket.onclose = function(event) { console.log('Client notified socket has closed',event); }; // 关闭Socket.... //socket.close() };
服务器端
jWebSocket (Java)
web-socket-ruby (ruby)
Socket IO-node (node.js)
下面以socket.io说明,环境说明:(node.js安装见 http://www.cnblogs.com/wishyouhappy/p/3647037.html)
1. 安装socket.io
npm install -g socket.io
2.使用require引入http和socket.io
var http = require("http"); var io= require('socket.io');
3.创建server
var server = http.createServer(function(request, response){ response.writeHead(200,{"Content-Type":"text/html"}); response.write("WebSocket Start~~~~~~~~~~~~"); response.end(""); }).listen(8000);
4.监听
var socket= io.listen(server);
5.例子:
var http = require("http"); var io= require('socket.io'); var server = http.createServer(function(request, response){ response.writeHead(200,{"Content-Type":"text/html"}); response.write("WebSocket Start~~~~~~~~~~~~"); response.end(""); }).listen(8000); var socket= io.listen(server); // 添加一个连接监听器 socket.on('connection', function(client){ client.on('message',function(event){ console.log('Received message from client!',event); }); client.on('disconnect',function(){ clearInterval(interval); console.log('Server has disconnected'); }); });
数据发送两种方式send和emit
使用send和emit都可以发送数据,但是emit可以自定义事件,如下:
emit:
//服务器 socket.on('connection', function(client){ client.on('message',function(event){ client.emit('emitMessage', { hello: 'messgge received, wish you happy'+new Date().toString() }); }); }); //客户端 socket.on('emitMessage',function(data) { document.getElementById("result").innerHTML+=data.hello + "<br />"; });
send:
//服务器 socket.on('connection', function(client){ client.send('hello, I am the server'); }); //客户端 socket.on('message',function(data) { document.getElementById("result").innerHTML+=data + "<br />"; });
实例:(socket.io)
客户端:
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>Insert title here</title> <style> div{ border-radius: 10px; border: 2px solid pink; width:800px; } </style> </head> <body> <h1></h1> <div id="result"></div> <script src="http://localhost:8000/socket.io/socket.io.js"></script> <script> //创建Socket.IO实例,建立连接 var socket = io.connect('http://localhost:8000'); // 添加一个连接监听器 socket.on('connect',function() { console.log('Client has connected to the server!'); }); // 添加一个连接监听器 socket.on('message',function(data) { document.getElementById("result").innerHTML+=data + "<br />"; }); socket.on('emitMessage',function(data) { document.getElementById("result").innerHTML+=data.hello + "<br />"; }); // 添加一个关闭连接的监听器 socket.on('disconnect',function() { console.log('The client has disconnected!'); }); // 通过Socket发送一条消息到服务器 function sendMessageToServer(message) { socket.send(message); } var date = new Date(); var ms="Time: "+date.toString()+"Today is a nice day, wish you happy"; setInterval("sendMessageToServer(ms)",1000); </script> </body> </html>
服务器:
var http = require("http"); var io= require('socket.io'); var server = http.createServer(function(request, response){ response.writeHead(200,{"Content-Type":"text/html"}); response.write("WebSocket Start~~~~~~~~~~~~"); response.end(""); }).listen(8000); var socket= io.listen(server); // 添加一个连接监听器 socket.on('connection', function(client){ client.on('message',function(event){ console.log('Received message from client!',event); client.emit('emitMessage', { hello: 'messgge received, wish you happy'+new Date().toString() }); }); client.on('disconnect',function(){ // clearInterval(interval); console.log('Server has disconnected'); }); client.send('hello, I am the server'); });
结果:
客户端:
服务器端:
相关博文:SSE及相关技术(web sockets, long polling等)