server.js

import Express      from 'express';
import Nunjucks     from 'nunjucks';
import BodyParser   from 'body-parser';
import cookieParser from 'cookie-parser';
import session      from 'express-session';

import * as Config from './config';
import * as LocalConfig from './locals';




export const App = Express();
export const Router = Express.Router();





export class Server {

	static launch() {

		/**
		 * Configure Nunjucks.
		 *
		 * 1. Autoescape is to safely escape HTML strings.
		 * 2. Declare App is using Express.
		 */
		Nunjucks.configure(Config.Server.viewPath, {
			autoescape: true,                              /* [1] */
			express: App                                   /* [2] */
		});





		/**
		 * Set Express envrionment defaults.
		 *
		 * 1. Set the default view engine.
		 * 2. Set the Express environment.
		 */
		App.set('view engine', Config.Server.viewEngine);  /* [1] */
		App.set('env', Config.Server.envrionment);         /* [2] */





		/**
		 * Define local variables to be used in templates.
		 */
		for (const key of Object.keys(LocalConfig.Locals)) {
			App.locals[key] = LocalConfig.Locals[key];
		}





		/**
		 * Set Express middleware.
		 *
		 * 1. Use Express .Router() middleware for routing.
		 * 2. Enable cookie parsing.
		 * 3. Enable body parsing, parsing the request input from the client-side.
		 * 4. Define the static asset URL.
		 * 5. Use session middleware to remember session states.
		 */
		App.use(Router);                                                                /* [1] */
		App.use(cookieParser());                                                        /* [2] */
		App.use(BodyParser.urlencoded({ extended: true }));                             /* [3] */
		App.use(`/${Config.Server.assetURL}`, Express.static(Config.Server.assetPath)); /* [4] */
		App.use(session({                                                               /* [5] */
			secret: '92463294092482374234723',
			name: `${Config.Server.namespace}-session`,
			resave: true,
			saveUninitialized: true
		}));





		/**
		 * Check if the configured environment is set to production.
		 */
		App.locals.isProduction = (App.get('env') === 'production');




		/**
		 * Listen on the configured port.
		 */
		let server = App.listen(Config.Server.port, !App.locals.isProduction ? Config.Server.host : '0.0.0.0', () => {
			console.log(`Server running @ http://${server.address().address}:${server.address().port}`);
		});
	}
}