I'm developing a calendar application with Node.js, express.js and Sequelize.
The application is simple, you can create tasks in your calendar, but you can also assign some tasks to others users of the system
I need to create a notification system with socket.io, but I don't have experience with websockets. My big doubt is how can I make my server send a notification to the user that you assign the task?
My ports configurations is on a folder called bin/www, my express routes are defined on a file called server.js
Any Idea?
I want to introduce you to ready to use backend system that enables you to easily build modern web applications with cool functionalities:
Persisted data: store your data and perform advanced searches on it.
Real-time notifications: subscribe to fine-grained subsets of data.
User Management: login, logout and security rules are no more a burden.
With this, you can focus to your main application development.
You can look at Kuzzle, wich is one project I working on:
First, start the service:
http://docs.kuzzle.io/guide/getting-started/#running-kuzzle-automagically
Then in your calendar application you can the javascript sdk
At this point you can create a document:
const
Kuzzle = require('kuzzle-sdk'),
kuzzle = new Kuzzle('http://localhost:7512');
const filter = {
equals: {
user: 'username'
}
}
// Subscribe every changes in calendar collection containing a field `user` equals to `username`
kuzzle
.collection('calendar', 'myproject')
.subscribe(filter, function(error, result) {
// triggered each time a document is updated/created !
// Here you can display a message in your application for instance
console.log('message received from kuzzle:', result)
})
// Each time you have to create a new task in your calendar, you can create a document that represent your task and persist it with kuzzle
const task = {
date: '2017-07-19T16:07:21.520Z',
title: 'my new task',
user: 'username'
}
// Creating a document from another app will notify all subscribers
kuzzle
.collection('calendar', 'myproject')
.createDocument(task)
I think this can help you :)
Documents are served though socket.io or native websockets when available
Don't hesitate to ask question ;)
As far as I can understand you need to pass your socket.io instance to other files, right ?
var sio = require('socket.io');
var io = sio();
app.io = io;
And you simply attach it to your server in your bin/www file
var io = app.io
io.attach(server);
Or what else I like to do, is adding socket.io middleware for express
// Socket.io middleware
app.use((req, res, next) => {
req.io = io;
next();
});
So you can access it in some of your router files
req.io.emit('newMsg', {
success: true
});
Related
I write a Node.Js app and I use Socket.Io as the data transfer system, so requests should be particular to per user. How can I make this?
My actual code;
node:
io.on('connection', (socket) => {
socket.on('loginP', data => {
console.log(data);
})
})
js:
var socket = io('',{forceNew : false});
$("#loginbutton").click(function() {
var sessionInfo = {
name : $("#login input[name='username']").val(),
pass : $("#login input[name='pass']").val()
}
socket.emit("loginP", sessionInfo)
})
It returns one more data for per request and this is a problem for me. Can I make this on Socket.Io or should I use another module, and If I should, which module?
If I understand your question correctly (It's possible I don't), you want to have just one connection from each user's browser to your nodejs program.
On the nodejs side, your io.on('connection'...) event fires with each new incoming user connection, and gives you the socket for that specific connection. So, keep track of your sockets; you'll have one socket per user.
On the browser side, you should build your code to ensure it only calls
var socket = io(path, ...);
once for each path (your path is ''). TheforceNew option is for situations where you have multiple paths from one program.
I've been working on a server and a push notification daemon that will both run simultaneously and interact with the same database. The idea behind this is that if one goes down, the other will still function.
I normally use Swift but for this project I'm writing it in Node, using Mongoose as my database. I've created a helper class that I import in both my server.js file and my notifier.js file.
const Mongoose = require('mongoose');
const Device = require('./device'); // This is a Schema
var uri = 'mongodb://localhost/devices';
function Database() {
Mongoose.connect(uri, { useMongoClient: true }, function(err) {
console.log('connected: ' + err);
});
}
Database.prototype.findDevice = function(params, callback) {
Device.findOne(params, function(err, device) {
// etc...
});
};
module.exports = Database;
Then separately from both server.js and notifier.js I create objects and query the database:
const Database = require('./db');
const db = new Database();
db.findDevice(params, function(err, device) {
// Simplified, but I edit and save things back to the database via db
device.token = 'blah';
device.save();
});
Is this safe to do? When working with Swift (and Objective-C) I'm always concerned about making things thread safe. Is this a concern? Should I be worried about race conditions and modifying the same files at the same time?
Also, bonus question: How does Mongoose share a connection between files (or processes?). For example Mongoose.connection.readyState returns the same thing from different files.
The short answer is "safe enough."
The long answer has to do with understanding what sort of consistency guarantees your system needs, how you've configured MongoDB, and whether there's any sharding or replication going on.
For the latter, you'll want to read about atomicity and consistency and perhaps also peek at write concern.
A good way to answer these questions, even when you think you've figured it out, is to test scenarios: Hammer a duplicate of your system with fake data and events and see if what happen is OK or not.
I have a MEAN app setup with npm socket.io with expressjs and btford.socket-io on the client.
angular.module('myApp',['btford.socket-io'])
.factory('socket',function(socketFactory){
return socketFactory();
}
).controller('myAppCtrl',['$scope','socket',
function(a,b){
b.on('test',function(data){
console.log(data);
});
}
]);
Here's the node-express setup:
var app = express(),
server = app.listen(3000);
var socket = require('socket.io'),
io = socket.listen(server);
require('/config/routes/index.js')(app,io);
require('/config/routes/test.js')(app,io);
Routes : (config/routes/index.js)
module.exports = function(app,io){
app.get('/',function(req,res){
io.on('connection',function(socket){
socket.join(req.session._id);
});
res.render('index');
});
};
config/routes/test.js
module.exports = function(app,io){
app.get('/route1',function(req,res){
io.to(req.session._id).emit('test',{
data : 'Works'
});
res.render('route1');
});
};
A) Whenever the user goes to route1, the emit event is being fired and sent to all the users.
B) Is there a better approach to avoid using unique room for each user? This is not a chat application but rather implements push notifications
You have a couple major misunderstandings about how sockets and requests work. They are very separate operations and are not connected the way you appear to think they are. I will try to explain the problems with your code.
In this block of code:
module.exports = function(app,io){
app.get('/',function(req,res){
io.on('connection',function(socket){
socket.join(req.session._id);
});
res.render('index');
});
};
You are processing the / page request and EVERY time that request is hit, you add yet another event handler for io.on('connection', ...), thus you could have many of those.
Further, if the connection event happens BEFORE the user hits the / page, then you will miss it entirely and that socket will not be placed into the proper chat room.
Then, in this block of code:
module.exports = function(app,io){
app.get('/route1',function(req,res){
io.to(req.session._id).emit('test',{
data : 'Works'
});
res.render('route1');
});
};
io.to() takes a string that is the name of a chat room. So, this will send a message to every socket that is in the req.session._id chat room. For this to work, you'd have to make absolutely sure that req.session._id was completely unique to this user and that the desired user had already joined a chat room by this name. This could work, but it depends upon those specific things being correct.
You need to think of the connection from socket.io separately from a request. They are NOT tied together the way that you think they are. Your connection listener is for any connection not just a connection related to a given request... what you are trying to do simply will not work that way.
Imagine that your socket.io portions of your project are completely separate from the http requests in the web/express portions of your application. This is how you should think of passing messages.
Also worth consideration is that if you are using cluster or similar scaling methods, your default socket.io setup in one instance doesn't communicate with other instances.
I have been building a simple application to learn angular.js. So far I hooked up all the pieces in the MEAN stack and I am able to save and retrieve data from Mongo.
The app is essentially a todo list. The user can create a project and inside the project create "cards" with "todos" which can then be moved from state to state ("backlog", "in progress", "complete", etc.)
I would like to be able to push the notifications to all the people who are connected to tell their apps that a refresh is needed to get the latest todos. In other words, let's say that user A adds a new card to project A, I would like to send a message out to all users who are currently watching project A so that their application issues a project refresh to get the latest and greatest.
Any suggestions on how to proceed? Which technology, if any, I need to add to the MEAN stack to be able to do something like this?
Thanks in advance
Since you're on the MEAN stack, the standard recommendation in Node would be to use the Socket.IO API.
They provide the following example of two way messaging (which would facilitate your push messages very easily):
Client
<script src="/socket.io/socket.io.js"></script>
<script>
var socket = io.connect('http://localhost');
socket.on('news', function (data) {
console.log(data);
socket.emit('my other event', { my: 'data' });
});
</script>
Server
var app = require('http').createServer(handler)
, io = require('socket.io').listen(app)
, fs = require('fs')
app.listen(80);
function handler (req, res) {
fs.readFile(__dirname + '/index.html',
function (err, data) {
if (err) {
res.writeHead(500);
return res.end('Error loading index.html');
}
res.writeHead(200);
res.end(data);
});
}
io.sockets.on('connection', function (socket) {
socket.emit('news', { hello: 'world' });
socket.on('my other event', function (data) {
console.log(data);
});
});
It will use websockets where possible, and fallback to AJAX long polling or Flash polling in browsers where there is no websocket support.
As for integrating with Angular, here's a good blog post on Socket.IO and Angular:
I'll be writing about how to integrate Socket.IO to add real-time
features to an AngularJS application. In this tutorial, I'm going to
walk through writing a instant messaging app.
If you're already working with Express, you should check out express.io.
It has a bunch of cool features like Session support and the ability to forward normal HTTP routes to realtime routes.
Here is a module we have written for getting AngularJS push notifications working in PhoneGap / Cordava (with full instructions):
http://www.scorchsoft.com/blog/free-angularjs-cordova-push-notification-plugin/
Simply download the example code and install. There is also code included for setting up the pushing component in PHP.
Why not with HTML5 Notification API....
export default class NotificationService {
/**
* Constructor of the class.
*
*/
constructor() {}
showPushNotification(title: string = '', message: string, iconPush) {
if (window.Notification && Notification.permission !== "denied") {
Notification.requestPermission(function(status) {
var n = new Notification(title, {
body: message,
icon: iconPush
});
});
}
}
}
I am working on a node.js project that I am leveraging Socket.IO in, and am having an issue getting my head around a scoping issue. Here is what I am trying to do:
var io = require('socket.io').listen(80);
session_manager = require('./includes/session_manager');
// client joins the socket server
io.sockets.on('connection', function(client) {
client.on('X.Session.join', function(session_id, client) {
session_manager.joinSession(session_id, function(err, session) {
// do whatever
});
});
// BRING IN MORE LISTENERS/EMITTERS?
require('someModuleIBuild');
});
As you can see I am basically setting up the initial connection, joining a session via a managing class (so I know who to emit to for which session) and then I am trying to dynamically bring in some custom stuff that ALSO is going to be emitting and listening via the socket connection.
So how do I reference this current connection from within the confines of my custom modules? All the examples I have seen have all the "on" and "emit" functions in one file, which seems like it could get out of control pretty quickly.
I am possibly over-thinking/over-complicating this (this is my first node.js project, first socket-based project, first mostly-javascript project....etc) but any help would be appreciated.
create your modules like this and you can pass the client into the module
module.exports = function(client) {
client.on("whatever", function () {
});
client.on("whenever", function (data) {
});
};
and then do the require like this
require('someModuleIBuild')(client);