server.js

var express = require('express');
var config = require('./env'); 

console.log(config);

app = express(),
http = require('http'),
socketIo = require('socket.io');

// start webserver on port 8080
var server =  http.createServer(app);
var io = socketIo.listen(server);
server.listen(config.port);
// add directory with our static files
app.use(express.static(__dirname + '/public'));
console.log("Server running on 127.0.0.1:8080");

// array of all lines drawn
var line_history = [];

// event-handler for new incoming connections
io.on('connection', function (socket) {

// first send the history to the new client
for (var i in line_history) {
socket.emit('draw_line', { line: line_history[i] } );
}

// add handler for message type "draw_line".
socket.on('draw_line', function (data) {
// add received line to history 
line_history.push(data.line);
// send line to all clients
io.emit('draw_line', { line: data.line });
});
});