实时通知node.js

Question

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'm have no experience with websockets. My big doubt is how can I make that my server sends a notification to the user that you assign the task?

My ports configurations is on a folder called bin/www, my express routes are difined on a file called server.js

Any Idea?

Answer 1

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 ;)

Answer 2

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
});