firing socket.emit() on http request - node.js

Question

Right now I have the following code: foo
sIo.sockets.on('connection', function(socket){
socket.emit('hello', 'world');
});
I would like to be able to emit this when somebody opens a page from my routes, like this:
//app.js
app.get('/send', routes.index);
//routes.js
exports.index = function(req, res){
socket.emit('hello', 'world');
};
How can I achieve this? Thanks in advance

Answer 1

To send a socket message to all connected sockets, you can just call io.sockets.emit instead of socket.emit. There are a few ways to send messages using socket.io which I'll outline below.
// Send the message to all connected clients
io.sockets.emit('message', data);
// Send the message to only this client
socket.emit('message', data);
// Send the messages to all clients, except this one.
socket.broadcast.emit('message', data);
There is also a concept of rooms which you can use to segment your clients.
// Have a client join a room.
socket.join('room')
// Send a message to all users in a particular room
io.sockets.in('room').emit('message', data);
All of that covers how to send messages, but it's clear now you're asking about how to access the socket and / or io objects from inside a separate file. One options just has you pass those dependencies to the specified file. Your require line will end up looking something like this.
var routes = require('./routes')(io);
Where io is the socket.io object created from .listen. To handle that in your route file you'll have to change how you're defining your exports.
module.exports = function(io) {
return {
index: function(req, res) {
io.sockets.emit('hello', 'world');
res.send('hello world');
}
};
}
A cleaner implementation would have your routes expose events that your socket code can bind to. The following is untested, but should be very close.
var util = require("util"),
events = require("events");
function MyRoute() {
events.EventEmitter.call(this);
}
util.inherits(MyRoute, events.EventEmitter);
MyRoute.prototype.index = function(req, res) {
this.emit('index');
res.send('hello world');
}
module.exports = new MyRoute();
And then in your app.js file when you're binding express routes and socket.io.
app.get('/send', routes.index);
routes.on('index', function() {
io.sockets.emit('hello', 'world');
});
There are many other ways to accomplish this, but the best one depends on what you're trying to do. As I alluded to before, calling broadcasting to everyone is going to be far more simple than broadcasting to a particular user.