服务端和客户端之间的通信
前端开发经常会依赖后端，那么如果后端服务器还没做好推送服务器，那么前端该如何呢。
最简单的就是自己模拟一个服务器，用node来搭建，这边只简单介绍搭建的过程
node搭建服务器
1.选取websocket插件进行开发
按照如下步骤进行开发
在命令台中输入以下命令
npm init -y
npm i websocket -S安装完websocket插件后就可以搭建服务器了，首先新建一个app.js，并且代码如下
var webSocketsServerPort = 3002
var webSocketServer = require('websocket').server
var http = require('http')
var server = http.createServer(function(req, res) {
})
server.listen(webSocketsServerPort, function() {
console.log((new Date()) + "Server is listening on port " + webSocketsServerPort)
})
/**
* websock server
*/
var wsServer = new webSocketServer({
httpServer: server
})
wsServer.on('request', function(request) {
var connection = request.accept(null, request.origin);
connection.on('message', function(message) {
console.log('message');
});
connection.on('close', function(connection) {
console.log('close');
});
})这样一个简易的服务器已经搭建完成。可以通过客户端进行测试(客户端代码见后面)
2.选取faye-websocket插件进行开发
在命令台中输入以下命令
npm init -y
npm i faye-websocket-S这种方式更简单了。代码如下
var WebSocket = require('faye-websocket'),
http = require('http');
var server = http.createServer();
server.on('upgrade', function(request, socket, body) {
if (WebSocket.isWebSocket(request)) {
var ws = new WebSocket(request, socket, body);
ws.on('message', function(event) {
ws.send(event.data);
});
ws.on('close', function(event) {
console.log('close', event.code, event.reason);
ws = null;
});
}
});
server.listen(3002);3.选取socket.io插件进行开发
该插件依赖于express
命令如下
express -e node-js-socketio // express模板安装
npm i // 安装express插件
npm i socket.io -S // 安装socket.ioapp.js文件改成如下代码
var app = require('express')()
, server = require('http').createServer(app)
, io = require('socket.io').listen(server);
server.listen(3002);
app.get('/', function (req, res) {
res.sendfile(__dirname + '/client/index.html');
});
io.sockets.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});至此 服务器搭建已经完成(还有一种是基于stomp.js,目前还没弄清楚node如何搭建，等知道后在补充)
客户端（即浏览器）调用服务器
1.简单的demo如下
<html>
<body>
<div id="output"></div>
<script>
function checkBrowser() {
if (window.WebSocket) {
log("This browser supports WebSocket!");
} else {
log("This browser does not support WebSocket.");
}
}
function setup() {
var wsServer = 'ws://localhost:3002';
var ws = new WebSocket(wsServer);
ws.onopen = function(e) {
log("Connected to WebSocket server.", e);
sendMessage("Conan");
};
ws.onclose = function(e) {
log("Disconnected", e);
};
ws.onmessage = function(e) {
log("RECEIVED: " + e.data, e);
ws.close();
}
ws.onerror = function(e) {
log('Error occured: ' + e.data, e);
};
var sendMessage = function(msg) {
ws.send(msg);
log("SEND : " + msg);
}
}
function log(s, e) {
var output = document.getElementById("output");
var p = document.createElement("p");
p.style.wordWrap = "break-word";
p.style.padding = "10px";
p.style.background = "#eee";
p.textContent = "LOG : " + s;
output.appendChild(p);
console.log("LOG : " + s, e);
}
checkBrowser();
setup();
</script>
</body>
</html>2.基于express的socket.io的demo如下
<!DOCTYPE html>
<html>
<head>
<title>socket.io</title>
</head>
<body>
<h1>socket.io</h1>
<p>Welcome to socket.io</p>
<script src="https://cdnjs.cloudflare.com/ajax/libs/socket.io/2.1.1/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost:3002');
socket.on('news', function (data) {
console.log(data);
socket.emit('my other event', { my: 'data' });
});
</script>
</body>
</html>3 基于AMQ的demo(目前还不知道服务器如何搭建，但客户端还是可以用的)
demo里放了3种模式，主要就是Queue和topic，消费和发布
Queue和topic的区别是一对多和多对多（QUEUE发送一个人消息之后，就消失了，而topic可以发送多个人）
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script type="stompjs"></script>
<script type="text/javascript">
// 3种模式
// QUeue是只有1对多模式，，topic多对多模式
// 1.消息发布者模式
var client = Stomp.overTCP('localhost', 61613);
// uncomment to print out the STOMP frames
var connectCallback = function(frame) {
var subscription = client.subscribe('/topic/FirstQueue', onMessage);
//subscription.unsubscribe();
};
var onMessage = function(message){
if (message.body) {
console.log("got message with body " + message.body)
} else {
console.log("got empty message");
}
};
var errorCallback = function(error){
console.log(error.headers.message);
};
client.connect('admin', 'admin', connectCallback,errorCallback);
// 2.Queue消息消费者
var Stomp = require('stompjs');
// Use raw TCP sockets
var client = Stomp.overTCP('localhost', 61613);
// uncomment to print out the STOMP frames
// client.debug = console.log;
var connectCallback = function(frame) {
var subscription = client.subscribe('/queue/FirstQueue', onMessage);
//subscription.unsubscribe();
};
var onMessage = function(message){
if (message.body) {
console.log("got message with body " + message.body)
} else {
console.log("got empty message");
}
};
var errorCallback = function(error){
console.log(error.headers.message);
};
client.connect('admin', 'admin', connectCallback,errorCallback);
// 3.topic 消息订阅者模式
// Use raw TCP sockets
var client = Stomp.overTCP('localhost', 61613);
// uncomment to print out the STOMP frames
// client.debug = console.log;
var connectCallback = function(frame) {
var subscription = client.subscribe('/topic/FirstQueue', onMessage);
//subscription.unsubscribe();
};
var onMessage = function(message){
if (message.body) {
console.log("got message with body " + message.body)
} else {
console.log("got empty message");
}
};
var errorCallback = function(error){
console.log(error.headers.message);
};
client.connect('admin', 'admin', connectCallback,errorCallback);
</script>
</body>
</html>
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