Proxy for multiple subdomains

proxy.js

//This script proxies multiple subdomains for a Meteor Application. More to edit.

"use strict";

var httpProxy = require('http-proxy'),
                http = require('http'),
                accesslog = require('access-log'),
                addresses;

var LISTENPORT = 80; //port we're listening to the outside world
var METEORPORT = 3000; //port meteor is run on the guests
var MINIP = 10; //Minimum IP address we can use. Smaller numbers are for admin purposes
var MYDOMAIN = 'devwik.com';
var LOCAL_SUBNET = '10.0.3.';
var currentMaxNumber = MINIP;
var devwikCollection;
var proxyServer = null;
var devwikDb = null


// routing hash
addresses = {
        /*
                 'foo.devwik.com:3180': {
                 host: '10.0.3.3',
                 port: METEORPORT
                 },
                 */
                 'www.devwik.com': {
                 host: 'localhost',
                 port: 3000
                 },
        //This is our testing server
                 'test.devwik.com': {
                 host: 'localhost',
                 port: 4000
                 },
        'default': {
                host: 'localhost',//by default go the devwik's main page if we don't match something we know.
                port: METEORPORT //TODO: do we want to send them to a 404 Not found.?
        }
};

var mongo = require('mongodb'),
                Server = mongo.Server,
                Db = mongo.Db;

//var server = new Server('localhost', 27017,  {safe:true});
var server = new Server('localhost', 27017);
//var db = new Db('devwik', server, {safe:true});
var db = new Db('devwik', server);
var devwikUsersHash;
db.open(function(err, db) {
        if(err) {
                throw(err);
        } else {
                devwikDb = db;
                loadUsers();
        }
});

//load the devwik Users first. 
function loadUsers(callBack) {

        //load the Devwik Users first and insert them into a hash
        devwikUsersHash = new Object();
        devwikDb.collection('DevwikUsers', function(err, devwikUsers) {
                if(err) {
                        throw(err);
                } else {
                        devwikCollection = devwikUsers;
                        var stream = devwikUsers.find({}).stream();
                        stream.on("data", function(devwikUser) {
                                var userNumber = devwikUser.userNumber;
                                //console.log(" id:" + devwikUser.meteorId + " userNumber:" + userNumber + " port:" + devwikUser.port + " app:" +  devwikUser.currentApp + " editor:" + devwikUser.editorType);
                                if(userNumber && (userNumber > currentMaxNumber)) { //find out what's the current highest number used
                                        currentMaxNumber = userNumber;
                                }
                                devwikUsersHash[devwikUser.meteorId] = devwikUser; //set it up for each lookup by id
                        });
                        stream.on("end", function() {
                                loadMeteorUsers();
                                if (callBack) {
                                        callBack();
                                }
                        });
                }
        });
}
//load the Meteor Users next. 
function loadMeteorUsers() {

        devwikDb.collection('users', function(err, users) {
                if(err) {
                        throw(err);
                } else {
                        var stream = users.find({},{sort: {createdAt: 1}}).stream();
                        stream.on("data", function(user) {
                                /*construct something like: 
                                        'foo.devwik.com': {
                                        host: '10.0.3.23',
                                        port: METEORPORT
                                        },
                                        */
                                var devwikUser = devwikUsersHash[user._id];
                                if (!devwikUser) {
                                        console.log('###Error. User:' + user.username + ' does not exist in devwikUser');
                                        return;
                                }
                                var userNumber = devwikUser.userNumber;
                                if (!userNumber) { //user doesn't currently have a number assigned
                                        currentMaxNumber++;
                                        userNumber = currentMaxNumber;//give them the next number
                                        console.log('Setting:' + user.username + " to:" + userNumber);
                                        //And update it in the db for future use an also to inform the app
                                        //TODO: race condition. Need to make sure that this is single threaded
                                        devwikCollection.update({meteorId:user._id},{$set: {userNumber: userNumber}});
                                }
                                var vhost = new Object();
                                var subDomain = user.username + '.' + MYDOMAIN;
                                vhost.host = LOCAL_SUBNET + (userNumber);
                                vhost.port = METEORPORT;
                                addresses[subDomain] = vhost;
                                //console.log(" name:" + user.username + " id" + user._id); 
                                //console.log(vhost);
                        });
                        stream.on("end", function() {
                                if (!proxyServer) {
                                        runProxy();//first time
                                }
                        });
                }
        });
}

console.log('Starting, pid:' + process.pid);

function runProxy() {

        proxyServer = httpProxy.createServer(function (request, response, proxy) {
                var target;
        //       accesslog(request, response);
        //
          var buffer = httpProxy.buffer(request);

                // if we have a host in the routing hash we proxy to it
                // otherwise we proxy to default host
                target = (addresses[request.headers.host]) ? addresses[request.headers.host] : addresses.default;
                target.buffer = buffer;
                proxy.proxyRequest(request, response, target);
        }).listen(LISTENPORT);

        console.log(addresses);

        proxyServer.proxy.on('proxyError', function (err, req, res) {
                res.writeHead(500, {
                        'Content-Type': 'text/html'
                });
                res.write('<html>\n');
                res.write('<body>\n');
                res.end("<h1> Not available </h1> Sorry, it looks like you've reached a site that is currently unavailable. <br/> Try later or check out <a href='http://www.devwik.com'>our home page at http://www.devwik.com'</a>.</body></html>");
                res.end("</body> </html>");

        });

}

http.createServer(function (request, response) {
        request.on("end", function () {
                //Called after the user is handled
                var callBack = function() {
                        response.writeHead(200, {
                                'Content-Type': 'text/plain'
                        });
                        response.end('OK');
                        console.log('reload');
                        console.log(addresses);
                };
        // Send data and end response.
        });

        loadUsers(callback);
}).listen(9999);


-----------------------------------------------------------------

/*
 * Contact the prox to let it know to check for a new user. 
 * 1. It will: find the user in the db
 * 2. Assign them a unique ID TODO: you need to create a unique index
 * 3. Update the db with the unique ID
 * 4. Associate the IP address with the user name/sub domain such as joe.devwik.com
 */

Devwik.notifyProxy = function notifyProxy(callback) {
        var options = {
                host: 'localhost',
                port: 9999,
                path: '/',
                method: 'GET'
        };

        var req = http.request(options, function(res) {
                console.log('STATUS: ' + res.statusCode);
                console.log('HEADERS: ' + JSON.stringify(res.headers));
                res.setEncoding('utf8');
                res.on('data', function (chunk) {
                        console.log('BODY: ' + chunk);
                        callback(chunk);
                });
        });

        req.on('error', function(e) {
                console.log('problem with request: ' + e.message);
        });

        // write data to request body
        req.write('data\n');
        req.write('data\n');
        req.end();
}