Option 3
When you update MySQL from PHP you publish those changes to node.js via redis publish
command(publish from PHP when mutating database). From node.js I would receive those changes in real-time thanks to Redis's subscribe. Then I would just broadcast them to users interested via socket.io. You could for example publish
to channel mysql
. Take for example the following SQL statement => INSERT INTO comments (1, "Hello World")
. Where 1
is something like userid, and Hello World
would be something like the comment. I probably would not publish SQL-statement to that channel, but JSON instead which I can easily use both from JavaScript(JSON.stringify / JSON.parse) and PHP(json_encode / json_decode).
Update
You don't run a cron-job because this would defeat the purpose off Redis's pubsub. Take for example I visit your website which is a blog at http://localhosts
. I read an article at http://localhost.com/a.php
. Below on the site you provide a form which I can use to post a comment to that article:
a.php
<html>
<head>
<title>Interesting blog post</title>
</head>
<body>
<div id="article">This is interesting</div>
<div id="comments">
<div class="comment">
<div class="from">Alfred Said at 22:34</div>
<div class="message">Hello World</div>
</div>
</div>
<form action="post.php" method="post">
<label for="name">Your name</label><br />
<input type="name" id="name" name="name" /><br />
<label for="message">Your Message:</label><br />
<textarea id="message" name="message"></textarea>
<input type="submit" />
</form>
<script src='jquery.min.js'></script>
<script src='http://localhost:8888/socket.io/socket.io.js'></script>
<script type="text/javascript">
$(document).ready(function () {
var socket = io.connect('http://localhost:8888');
socket.on('message', function (json) {
var obj = $.parseJSON(json);
alert('in here: ' + obj.name);
});
});
</script>
</body>
</html>
I submit the form which has action attribute http://localhost/postcomment.php
. But this is the important part! At post.php
you retrieve the data I posted and insert it into MySQL using INSERT INTO comments (1, "Hello World")
. When this mutation happens you also need to inform node.js process which is continually listening to channel mysql
:
post.php:
<?php
$_POST = filter_input_array(INPUT_POST, FILTER_SANITIZE_STRING);
require("./Predis.php");
$redis = new Predis\Client();
$obj = array(
'name' => $_POST['name'],
'message' => $_POST['message']
);
$json = json_encode($obj);
$redis->publish("mysql", $json);
echo $json;
post.php requires predis.
The node code with node_redis would look something like:
var redis = require('redis'),
subscriber = redis.createClient(),
express = require('express'),
store = new express.session.MemoryStore(),
app = express.createServer(
express.bodyParser(),
express.static(__dirname + '/public'),
express.cookieParser(),
express.session({ secret: 'htuayreve', store: store}))
sio = require('socket.io');
app.listen(8888, '127.0.0.1', function () {
var addr = app.address();
console.log('app listening on http://' + addr.address + ':' + addr.port);
});
var io = sio.listen(app);
io.configure(function () {
io.set('log level', 1); // reduce logging
});
io.sockets.on('connection', function (socket) {
socket.join('mysql');
socket.on('disconnect', function () {
});
});
subscriber.on('message', function (channel, json) {
// this will always retrieve messages posted to mysql
io.sockets.in('mysql').json.send(json);
});
subscriber.subscribe('mysql');
This samples depends on the following packages, which you can install via npm
npm install socket.io
npm install redis
npm install express
Always when I post the form post.php
, I also publish these changes to redis. This part is important! The node.js process is always receiving those changes thanks to Redis's pubsub. Every time when a php script mutates the database you should publish these changes to Redis with publish
.
P.S: Hope this is clear. Maybe later when I have some time available I update with maybe little snippet...