I have created a basic chatroom application using a node express server. This application relies on a redis database for storing the nicknames of all connected clients.
Now, I am looking to implement a feature that clears the redis SET named members when the server is closed or disconnected. The code snippet to achieve this is as follows:
redisClient.del("members", function(err, reply){
console.log("members set delete :" + reply);
});
However, I am unsure about where to place this code and how to handle the final event triggered by the server upon disconnection from the server side.
Server-side code - chatroom.js
var express = require('express');
var app = express();
var server = require('http').createServer(app);
var io = require('socket.io')(server);
var redis = require('redis');
var redisClient = redis.createClient();
io.on('connection', function(client){
console.log("client connected...");
});
io.on('connection', function(client){
client.on('join', function(name){
client.nickname = name;
// Adding names
client.broadcast.emit("add member", name);
redisClient.smembers('members', function(err, names) {
names.forEach(function(name){
client.emit('add member', name);
});
});
client.emit('add member', client.nickname)
redisClient.sadd("members", name);
});
// Remove clients on disconnect
client.on('disconnect', function(name){
client.broadcast.emit("remove member", client.nickname);
redisClient.srem("members", client.nickname);
});
});
app.get('/', function(req, res){
res.sendFile(__dirname + '/views/index.html');
});
server.listen(8080);
Client-side code - views/index.html
<html>
<head>
<title>Socket.io Client</title>
<script src="/socket.io/socket.io.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
</head>
<body>
<h2>Chat box</h2><br>
<h4 id="status"></h4><br>
<div>
<h3>Active members</h3>
<ul id="members"></ul>
</div>
<script>
var socket = io.connect('http://localhost:8080');
socket.on('connect', function(data){
nickname = prompt("What is your nickname?");
$('#status').html('Connected to Chat Room as \''+nickname+'\'.');
socket.emit('join', nickname);
});
socket.on('add member', function(name) {
var member = $('<li>'+name+'</li>').data('name', name);
$('#members').append(member);
});
socket.on('remove member', function(name) {
$('#members li').filter(function() { return $.text([this]) === name; }).remove();
});
socket.on('disconnect', function(data){
$('#status').html('Chatroom Server Down!');
});
</script>
</body>
</html>
How can I clear the redis database set when my nodejs server disconnects?