How I got tickets to the Gymnastics finals at the Olympics

tix.js

/* This node.js script checks the Olympics website for any new Women's
 * Gymnastics tickets. Every five minutes it fetches the available tickets
 * page for the event, and uses the cheerio (https://npmjs.org/package/cheerio)
 * module to parse the page and look for the UI element that indicates there
 * are tickets.
 *
 * If there are any tickets it plays a song using node's built in `exec()`
 * function to call OS X's command line utility to play a sound file. It also
 * uses the growl module (https://npmjs.org/package/growl) to post a growl
 * notification.
 *
 * To run the script, get node.js (http://nodejs.org/). Open up the Terminal
 * and install the cheerio and growl modules with the commands
 * `npm install cheerio` and `npm install growl`. If you use growl you'll
 * also need the growlnotify app (http://growl.info/extras.php#growlnotify).
 *
 * If you're not on OS X, growl won't work, but you can replace `afplay` with
 * your OS's built in command to play sound.
 *
 * Then run the script with `node tix.js`
 */

var request = require('request'),
    growl = require("growl"),
    cheerio = require("cheerio"),
    exec = require('child_process').exec;

var sessionURL = "http://www.tickets.london2012.com/eventdetails?id=0000455ACD8C0B72";
var fiveMinutes = 1000 * 60 * 5;

// check tickets once
checkTickets();

// then check tickets every five minutes
setInterval(checkTickets, fiveMinutes);

function checkTickets() {
  console.log("checking for tickets");

  request(sessionURL, function (error, response, body) {
    if (error) {
      console.log(error);
    }
    else if (response.statusCode != 200) {
      console.log(response.statusCode, "error");
    }
    else if (hasSeats(body)) {
      celebrate();
    }
  })
}

function hasSeats(html) {
  var $ = cheerio.load(html);
  var elements = $("select#price_category > option");

  return elements.toArray().length;
}


function celebrate() {
  console.log("Gymnastics tickets found!");

  // play a song
  exec("afplay ~/heartbreaker.mp3", function(err) {
    if (err) console.log(err);
  });

  // post a growl notification
  growl("Women's gymnastics tickets available!", {
    title: "Tickets available",
    sticky: true,
    image: "./gymnast.jpg"
  });
}

Steps to run:

1. Install node.js

2. Install required packages with npm install cheerio request growl

3. run with node tix.js