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    <h1>OLD only use a reference</h1> <h2>Dependencies</h2> <p>uses <a href="http://expressjs.com/">express</a>, <a href="http://socket.io">socket.io</a>, <a href="https://github.com/mranney/node_redis">node_redis</a> and last but not least the <a href="http://www.mediafire.com/?94iz516qwar10ew">sample code</a> from media fire.</p> <h2>Install node.js+npm(as non root)</h2> <p>First you should(if you have not done this yet) install <a href="https://gist.github.com/579814#file_node_and_npm_in_30_seconds.sh">node.js+npm in 30 seconds</a> (the right way because you should <strong>NOT</strong> run npm as <strong>root</strong>):</p> <pre><code>echo 'export PATH=$HOME/local/bin:$PATH' &gt;&gt; ~/.bashrc . ~/.bashrc mkdir ~/local mkdir ~/node-latest-install cd ~/node-latest-install curl http://nodejs.org/dist/node-latest.tar.gz | tar xz --strip-components=1 ./configure --prefix=~/local make install # ok, fine, this step probably takes more than 30 seconds... curl http://npmjs.org/install.sh | sh </code></pre> <h2>Install dependencies</h2> <p>After you installed node+npm you should install dependencies by issuing:</p> <pre><code>npm install express npm install socket.io npm install hiredis redis # hiredis to use c binding for redis =&gt; FAST :) </code></pre> <h2>Download sample</h2> <p>You can download complete sample from <a href="http://www.mediafire.com/?94iz516qwar10ew">mediafire</a>.</p> <h2>Unzip package</h2> <pre><code>unzip pbsb.zip # can also do via graphical interface if you prefer. </code></pre> <h2>What's inside zip</h2> <p><strong>./app.js</strong></p> <pre><code>const PORT = 3000; const HOST = 'localhost'; var express = require('express'); var app = module.exports = express.createServer(); app.use(express.staticProvider(__dirname + '/public')); const redis = require('redis'); const client = redis.createClient(); const io = require('socket.io'); if (!module.parent) { app.listen(PORT, HOST); console.log("Express server listening on port %d", app.address().port) const socket = io.listen(app); socket.on('connection', function(client) { const subscribe = redis.createClient(); subscribe.subscribe('pubsub'); // listen to messages from channel pubsub subscribe.on("message", function(channel, message) { client.send(message); }); client.on('message', function(msg) { }); client.on('disconnect', function() { subscribe.quit(); }); }); } </code></pre> <p><strong>./public/index.html</strong></p> <pre><code>&lt;html&gt; &lt;head&gt; &lt;title&gt;PubSub&lt;/title&gt; &lt;script src="/socket.io/socket.io.js"&gt;&lt;/script&gt; &lt;script src="/javascripts/jquery-1.4.3.min.js"&gt;&lt;/script&gt; &lt;/head&gt; &lt;body&gt; &lt;div id="content"&gt;&lt;/div&gt; &lt;script&gt; $(document).ready(function() { var socket = new io.Socket('localhost', {port: 3000, rememberTransport: false/*, transports: ['xhr-polling']*/}); var content = $('#content'); socket.on('connect', function() { }); socket.on('message', function(message){ content.prepend(message + '&lt;br /&gt;'); }) ; socket.on('disconnect', function() { console.log('disconnected'); content.html("&lt;b&gt;Disconnected!&lt;/b&gt;"); }); socket.connect(); }); &lt;/script&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> <h2>Start server</h2> <pre><code>cd pbsb node app.js </code></pre> <h2>Start browser</h2> <p>Best if you start google chrome(because of websockets support, but not necessary). Visit <code>http://localhost:3000</code> to see sample(in the beginning you don't see anything but <code>PubSub</code> as title).</p> <p>But on <code>publish</code> to channel <code>pubsub</code> you should see a message. Below we publish <code>"Hello world!"</code> to the browser.</p> <h2>From ./redis-cli</h2> <pre><code>publish pubsub "Hello world!" </code></pre>
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    1. POHow to use redis PUBLISH/SUBSCRIBE with nodejs to notify clients when data values change?
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    1. COwhy do you need `const client = redis.createClient()` in the root of app.js?
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    2. COyou don't need to use const at all. var could be used as well and maybe I should have instead because const is only available in the newer javascript engines. Furthermore this line ensures we are connected to redis server which we use in this example.
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    3. CO@Alfred I tried your example and it seems that it never goes in the socket.on('connection', function(client) { block. I tried to print something there and never does. if I remove this part I can normally publish and see the message in the console. Also when I run pubsub.js the following are printed on the console: Express server listening on port3000 info - socket.io started Do you maybe have an idea of what might be wrong in my case?
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