comet.server.js

/*global Buffer: false, clearInterval: false, clearTimeout: false, console: false, exports: false,
  global: false, module: false, process: false, querystring: false,
  require: false, setInterval: false, setTimeout: false, '__filename': false, '__dirname': false */
"use strict";

var dataArrayByCanal = [],
    port = process.argv[2];

if (port === undefined) {
    console.log('Error: Port is not specified. Port must be passed as first argument');
    process.exit(1);
}

var isCacheable = process.argv[3] === 'cache',
    http = require('http'),
    url = require('url'),
    formidable = require('/usr/local/lib/node_modules/formidable');

var ClientManager = function () {
        var clients = [],
            me = this;

        this.registerClient = function (canal, client) {
            if (!clients[canal]) {
                clients[canal] = [];
            }
            clients[canal].push(client);
        };

        this.broadcastData = function (canal, data) {
            var i;
            if (clients[canal]) {
                for (i = 0; i < clients[canal].length; i += 1) {
                    me.writeData(clients[canal][i], data);
                }
                clients[canal] = [];
            }
        };

        this.writeData = function (res, data) {
            res.writeHeader(200, {'Content-Type': 'application/json;charset=utf-8'});
            res.write(data, 'utf-8');
            res.end();
        };
    },
    clientManager = new ClientManager();

http.createServer(function (req, res) {
    var urlParsed = url.parse(req.url, true),
        canal = urlParsed.query.canal,
        form;

    switch (urlParsed.pathname) {
    case '/publish':
        form = new formidable.IncomingForm();
        form.parse(req, function (err, fields, files) {
            var data = fields.data || '';

            if (!isCacheable || dataArrayByCanal[canal] !== data) {
                if (isCacheable) {
                    dataArrayByCanal[canal] = data;
                }
                clientManager.broadcastData(canal, data);
                console.log('publish to ' + canal + ' canal');
            }
            clientManager.writeData(res, 'ok');
        });
        break;

    case '/subscribe':
        clientManager.registerClient(canal, res);
        if (isCacheable && dataArrayByCanal[canal] && urlParsed.query.first) {
            console.log(console.log('publish to ' + canal + ' canal during subscribe'));
            clientManager.broadcastData(canal, dataArrayByCanal[canal]);
        }
        console.log('subscribe to ' + canal + ' canal');
        break;
    }

}).listen(port);