server.js

var express = require('express');
var app = express();

// Configure ejs engine
app.set('views', __dirname + '/public');
app.engine('html', require('ejs').renderFile);

// Force HTTPS on stackedit.io
app.all('*', function(req, res, next) {
    if (req.headers.host == 'stackedit.io' && req.headers['x-forwarded-proto'] != 'https') {
        res.redirect('https://stackedit.io' + req.url);
    }
    else {
        next();
    }
});

// Use gzip compression
app.use(express.compress());

// Serve static resources
app.use(express.static(__dirname + '/public'));

// Serve viewer.html in /viewer
app.get('/viewer', function (req, res) {
    res.render('viewer.html');
});

// Error 404
app.use(function(req, res, next) {
    res.status(404);
    res.render('error_404.html');
});

// Listen on port 3000
var port = process.env.PORT || 3000;
app.listen(port, null, function() {
    console.log('Server started: http://localhost:' + port);
});