Express.io

Introducing... Express.io!

The power of Express.js with WebSockets

I've recently started a new project that requires something a little different from the usual MEAN stack. I needed to route static resources (easy, with the power of Express.js) but I also needed to manage WebSocket connections for a thick-client setup. I found that while Express.io essentially takes the same amount of time to setup, it has syntactical sugar benefits that were beneficial to the project in the long run.

Examples

Let's look at examples of separate Express.js/Sockets.io, and then Express.io.

Express.js + Sockets.io

var express = require('express');
var app = express.createServer();
var io = require('socket.io')(app);

io.on('connection', function (socket) {
  socket.emit('news', { hello: 'world' });
  socket.on('my other event', function (data) {
    console.log(data);
  });
});

app.listen(80);

Express.io

app = require('express.io')()
app.http().io()

// Setup the ready route, and emit talk event.
app.io.route('ready', function(req) {
    req.io.emit('talk', {
        message: 'io event from an io route on the server'
    })
})

app.listen(7076)

I omitted the static file serving code from both because they were the exact same.

Thoughts

You will notice that combining Express.js and WebSockets.io uses essentially two different vocabularies - app.get(dir, route) for a Express route, and io.on(socketEvent, callback) for a WebSocket event. While not totally jarring, it did not hold a candle to the smoother Express.io app.get() and app.io.route(). I also liked that app.io.route callbacks mimicked the res.send() methods I had grown so accustomed to.

Any cleaner routing is a win in my book!

Bonus Round - "Realtime Routing"

Express.io features something it calls "Realtime Routing" - essentially the ability to route within a route!

From the express.io GitHub page:

app.io.route('customers', {
    create: function(req) {
        // create your customer
    },
    update: function(req) {
        // update your customer
    },
    remove: function(req) {
        // remove your customer
    },
});

And then on the client you would emit these events:
    customers:create
    customers:update
    customers:delete

Scaffolding for me has always been a subtle pain, and I expect to have to wire a lot of connections in the coming weeks. I look forward to using Express.io to slide through with ease!