WebFund 2013F: Tutorial 7

Today you should spend your time understanding the following code. This is a complete node application. Consider the following:

• What does each line do? Specifically, what errors/loss of functionality would you lose if you remove any line?
• What node functionality has been omitted from this application relative to the other ones we have covered this term?
• How would you get this application to run?
• Where are functions being defined? Called?

The midterm will primarily cover this code. So this is your chance to prepare. Good luck!

package.json

{
  "name": "application-name",
  "version": "0.0.1",
  "private": true,
  "scripts": {
    "start": "node app.js"
  },
  "dependencies": {
    "express": "3.4.0",
    "jade": "*"
   }
}

app.js

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

var i, theRoom, loggedInUsers = {};
var rooms = { activeRooms: ['sickbay', 'engineering'],
              engineering: { title: "Engineering", roomExits: ['sickbay'] },
              sickbay: { title: "Sickbay", roomExits: ['engineering'] } };

function index(req, res) {
    if (req.session.player) {
        res.redirect("/" + req.session.currentRoom);
    } else {
        res.render('index', { title: 'COMP 2406 Small Adventure Demo', 
                              error: req.query.error }); }}

function start(req, res) {
    req.session.player = req.body.player;
    res.redirect("/engineering") }

function quit(req, res) {
    req.session.destroy();
    res.redirect("/"); }

function makeRoomHandler(name, contents) {
    handler = function(req, res) {
        if (req.session.player) {
            req.session.currentRoom = name;
            res.render("room.jade", {title: contents.title,
                                     roomExits: contents.roomExits,
                                     player: req.session.player});
        } else { res.redirect("/"); }}
    return handler; }

app.set('port', process.env.PORT || 3000);
app.set('views', __dirname);
app.set('view engine', 'jade');
app.use(express.logger('dev'));
app.use(express.bodyParser());
app.use(express.cookieParser('COMP2406 is confusing!'));
app.use(express.session());

app.get('/', index);
app.post("/start", start);
app.post("/quit", quit);
for (i = 0; i<rooms.activeRooms.length; i++) {
    theRoom = rooms.activeRooms[i];
    app.get('/' + theRoom,
            makeRoomHandler(theRoom, rooms[theRoom])); }

http.createServer(app).listen(app.get('port'), function(){
    console.log('Express server listening on port ' + app.get('port')); });

room.jade

doctype 5
html
  head
    title= title
  body
    h1= title
    p You're on a ship, player.
    p Go to:
    ul
      each theExit in roomExits
        li
          a(href= theExit) #{theExit}
    form(action="/quit", method="post")
      button(type="submit") Quit

index.jade

doctype 5
html
  head
    title= title
  body
    h1= title
    p Welcome to the #{title}
    p Please choose your player name
    div
      form(action="/start", method="post")
          div
            input(type="text", name="player")          
            label.add-on(for="player") Player Name
          button(type="submit") Start