Question

I’m having a hard time putting all these three together, probably because I’m not getting properly the concept of routing with Express.

I have a RabbitMQ queue with event updates. We can recognize these events by their id. So I want to get on a given page about an event, just the updates corresponding to its id.

Queue: 1316, 1539, 3486, 3479, 1316, 3890, 3479, … -> Feed from the DB indefinitely.
http://www.example.com/event/1316 -> Gets from the queue just messages with id 1316
http://www.example.com/event/3479 -> Gets from the queue just messages with id 3479

My code works good when I load the first event, but when I load the second one in a different window, it gets messages from both events, and if I load a third one, guess right, it gets messages from the three ids.

app.js

var express = require('express')  
, http = require('http');
var app = express();
var server = http.createServer(app);
var io = require('socket.io').listen(server, { log: false });
require('./io')(io);

var amqp = require('amqp');
var rabbitMQ = amqp.createConnection({ host: 'localhost' });

rabbitMQ.on('ready', function() {
  console.log('Connected to RabbitMQ');
  io.sockets.on('connection', function (socket) {
    console.log('Socket connected: ' + socket.id);
    rabbitMQ.queue('offer', { autoDelete: false, durable: false, exclusive: false }, function(q) {    
      q.bind('#'); // Catch all messages    
      q.subscribe(function (message) {
        obj = JSON.parse(message.data.toString());
        //socket.broadcast.to(obj.id).emit('message', obj);
        io.sockets.in(obj.id).emit('message', obj);
      });
    });
  });
});

var routes = require('./routes')
, event = require('./routes/event');

app.get('/', routes.index);
app.get('/event/:id', event.index);

server.listen(app.get('port'), function(){
  console.log("Express server listening on port " + app.get('port'));
});

io.js

var socketio = function (io) { 
  if (!io) return socketio._io;  
  socketio._io = io;
} 

module.exports = socketio;

routes/event.js

var io = require('../io')();

exports.index = function(req, res) {
  io.sockets.on('connection', function (socket) {
    socket.join(req.params.id);
  });
  res.render('event', { title: 'Event' });
};

Thanks!

Answer 1

After trying and failing, I have understood what I was doing wrong cause using io.sockets.on('connection') inside of the router was duplicating the event. So at the end, the simplest way of thinking is the right one.

app.js

var room = '';
var roomHandler = function(req, res, next) {
  if (req.path.match('event')) {
    room = req.params.id;
  } 
  next(); // Passing the request to the next handler in the stack.
}

io.sockets.on('connection', function (socket) {    
  socket.join(room);
});

rabbitMQ.on('ready', function() { 
  rabbitMQ.queue('offer', { autoDelete: false, durable: false, exclusive: false }, function(q) {      
    q.bind('#'); // Catch all messages  
    q.subscribe(function (message) {
      obj = JSON.parse(message.data.toString());
      io.sockets.in(obj.id).emit('message', obj);
    });
  });
});

app.get('/', routes.index);
app.get('/event/:id', roomHandler, event.index);