在这篇文章Redis数据库及其基本操作中介绍了Redis及redis-cli的基本操作. 其中的publish-subscribe机制应用比较广泛, 那么接下来使用nodejs来实现该机制. 本文是对之前的一篇文章使用socket.io+redis来实现基本的聊天室应用场景的详细补充.
关于redis的详细情况, 请参考Redis数据库及其基本操作.
对于redis的前提是redis-server一直在运行, 这里就使用默认的localhost:6379.
安装redis模块, 该模块会默认安装至当前目录下的node_modules里边:
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<code class="language-shell hljs cmake">npm install redis</code> |
然后连接redis, 并进行get-set操作
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<code class="language-node.js hljs php">var redis = require(‘redis‘);var redisclient = redis.createClient();redisclient.on(‘connect‘,function(){ redisclient.set(‘author‘, ‘testauthor‘, redis.print); redisclient.get(‘author‘, redis.print); redisclient.get(‘hello‘, redis.print);});</code> |
执行结果:
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<code class="language-shell hljs avrasm">? socketio node redis_node.jsReply: OKReply: testauthorReply: world</code> |
代码如下:
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<code class="language-node.js hljs perl">var redis = require(‘redis‘);var redisclient = redis.createClient();var sub = function(c) { var c = c || ‘chatchannel‘; redisclient.subscribe(c, function(e) { console.log(‘subscribe channel : ‘ + c); });}sub();redisclient.on(‘message‘, function(error, response) { console.log(response);})</code> |
另外启动了一个redis-cli的subscribe, 进行比较, 执行结果:![技术分享](http://www.2cto.com/uploadfile/Collfiles/20150517/20150517090705158.png "\")
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<code class="language-node.js hljs javascript">var http = require(‘http‘);// var server = http.createServer().listen(4000);http.createServer(function (request, response) { response.writeHead(200, {‘Content-Type‘: ‘text/plain‘}); response.end(‘Hello World\n‘);}).listen(4000); |
执行即可看到:![技术分享](http://www.2cto.com/uploadfile/Collfiles/20150517/20150517090705159.png "\")
socket.io连接于browser和nodejs的http服务器之间,可用于二者之间同步数据.
server端: 启动httpserver监听4000端口, 一旦有socket.io的连接建立, 则向socket发送msgReceived消息, 而消息内容是’hello’.
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<code class="language-node.js hljs lua">var server = require(‘http‘).createServer(function (request, response) { response.writeHead(200, {‘Content-Type‘: ‘text/plain‘}); response.end(‘Hello World\n‘);}).listen(4000);var io = require(‘socket.io‘)(server);io.on(‘connection‘, function(socket) { console.log(‘connection‘); socket.emit(‘msgReceived‘, ‘hello‘);})</code> |
browser端:
建立socket连接, 然后接收socket上的msgReceived消息, 并显示出来.
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<script src="https://cdn.socket.io/socket.io-1.3.5.js"></script>hello world <script type="text/javascript"> console.log("hello"); var socket = io(‘http://localhost:4000‘); socket.on(‘connection‘, function() { console.log(‘connection setup for socket.io‘) }); socket.on(‘msgReceived‘, function(msg) { alert(msg); }) </script>
为了方便看到更好的效果, 将两个browser都打开, 当httpserver未启动时, browser中仅显示 hello world. 一旦启动httpserver: node testserver.js, 就可以看到, 两个browser都会自动弹出alert, 表明接收到了socket.io中的消息. 执行结果如下图:![技术分享](http://www.2cto.com/uploadfile/Collfiles/20150517/20150517090706160.png "\")
然后, 停止httpserver, 将发送msgReceived消息的内容更改为’world’, 两个browser又再次弹出对应的alert. 如下图:
vcr9vt3NrLK9LiDV4sDvvs3KxywgaHR0cHNlcnZlcrfWsfC9q2hlbGxvus13b3JsZLSrtd24+MHLYnJvd3Nlci48L3A+DQo8aDIgaWQ9"将subscribe的结果在browser中展示">将subscribe的结果在browser中展示
接下来要做的是, 通过httpserver订阅redis的chatchannel频道, 将该频道发布的内容更新到browser中.
browser端不变, 而server端改为:
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<code class="language-node.js hljs javascript">var server = require(‘http‘).createServer(function (request, response) { response.writeHead(200, {‘Content-Type‘: ‘text/plain‘}); response.end(‘Hello World\n‘);}).listen(4000);var redis = require(‘redis‘);var redisclient = redis.createClient();var sub = function(c) { var c = c || ‘chatchannel‘; redisclient.subscribe(c, function(e) { console.log(‘subscribe channel : ‘ + c); });}sub();var io = require(‘socket.io‘)(server);io.on(‘connection‘, function(socket) { redisclient.on(‘message‘, function(error, msg) { console.log(‘connection‘); console.log(msg); socket.emit(‘msgReceived‘, msg); });})</code> |
首先redisclient订阅redis-server的chatchannel频道, 在socket.io连接建立时, 监听redisclient的消息, 一旦接收到chatchannel频道发布的消息, 立即通过socket.io向所有建立连接的browser发送msgReceived消息, 内容是chatchannel频道的发布内容. 我们这里, 采用redis-cli来发布消息, 当然也可以采用其他方法.
执行结果如下:
首先, redis-cli并未发布消息![技术分享](http://www.2cto.com/uploadfile/Collfiles/20150517/20150517090707162.png "\")
然后, 发布消息’how are you’, 两个browser都会收到:![技术分享](http://www.2cto.com/uploadfile/Collfiles/20150517/20150517090708163.png "\")
最后, 发布消息’thank you, goodbye’, 两个browser都会收到:
至此, 使用node.js和socket.io, 结合redis的publish-subscribe机制, 实现的聊天室场景就基本可行了.
使用node.js + socket.io + redis实现基本的聊天室场景
原文：http://www.cnblogs.com/youlechang123/p/5143673.html