Nice Videos From Recent Talks

A small selection from videos of recent good talks.

JavaScript: The Language
Nice advanced introduction to JavaScript and the new features of ECMAScript5

more all MIX 11 sessions

CHI 2011
Bill Buxton Shows Us His Favorite Tech
Why we need to remember past gadgets!

Google IO 2011
Java Puzzlers – Scraping the Bottom of the Barrel
The one and only java puzzlers, always informative.

Programming Well with Others: Social Skills for Geeks
Insights on geek vs/and management. You might also be interested in the book “Being Geek

HTML5 Showcase for Web Developers: The Wow and the How
Fun stuff with some chrome specific audio and file api, but also standard CSS3 3D animations.

more All Google IO 11 Sessions

ARDrone SDK 1.6 working windows client binary

Since there does not seem to be an official binary of the windows client sample for controlling the ARDrone. I decided to compile the sample project, which is available in the official sdk. Sadly the process of compiling the sample is not straight forward and requires a lot of tweaking [1, 2]. Nonetheless, I finally managed to compile a version, which is working on windows 7 x64 and is compatible with firmware update 1.5.1 of the ARDrone. It can be downloaded here:

ARDrone1.6Win32Client.exe working binary of ARDrone SDK 1.6 win32 client

You will also need to have an update to date version of the DirectX End-User Runtime [3].


Connect Galaxy Tab With ARDrone’s Ad hoc Network

In order to use any of the available ARDrone application for Android, the Samsung Galaxy Tab has to be connected to the ARDrone. Unfortunately, this is done via ad hoc network, a functionality not activated on the Galaxy Tab [1].

As with any problems there are different solutions, one of them is to ROOT the device and replace the WiFi functionality with a patched version.


I) Root the Samsung Galaxy Tab [2] (tested with SuperOneClick v1.9.1)

– Kies Software downloaded from HERE and installed and Tab connected at least once to the pc.
– SuperOnceClick downloaded from HERE

1) Connect your galaxy tab with debugging mode disabled and sync with Kies at least once.
2) Disconnect it and enable debugging mode from Settings>Applications>Development>USB Debugging
3) Connect the tab again to PC and click on home button so that Tab comes out of Kies connection
4) Launch SuperOneClick.exe, on Vista/Seven be sure to run as Administrator (right click run as…)
5) Click on root and wait for 5-10 Mins
6) Reboot when/if told to

II) Copy patched file onto device and overwrite [3]

1) Download wpa_supplicant HERE (use 7-zip to extract) or HERE (zip not tested)
2) upload file onto your device with adb push or connected as an USB drive
3) disable WiFi on the device
4) mount /system as read write ( there is also an app for that mount /system rw )
5) replace /system/wpa_supplicant (if your favorite explorer does not work, try a terminal)
5b1) > su
5b2) > cp /sdcard/wpa_supplicant /system/bin/wpa_supplicant
6) enable WiFi (you can now see and connect to Ad hoc networks!)

On a first test run all applications seem to be able to connect to the ARDrone with firmware 1.5.1: ARDrone Demo, ARDroid, Androne Freeflight.AR (slow video)


Browsing iTunesU without intalling iTunes

Updated version of the script

On some pages the location-bar information is available (third-level pages), but 1st and 2nd level pages do not have a location-bar. Even in iTunes it has been removed in favor of a location-bar managed by iTunes. I suppose this is done in order to make use of a cached version of the page and speed up loading. Having no location-bar at 2nd level pages is an awkward design choice from Apple. Therefore location-bar has to be managed by the script and 3th level pages need also to be re-adapted to be displayed correctly.

Fixed version can be tested here:[itunesU url]

the new source files are available here:
complete source code at github

index_fixed.groovy – new version with navigation fixed
proxy.groovy – proxy class because iTunes checks user-agent to link to some video files behind a redirect.

The problem

More and more universities publish courses as podcasts on iTunesU and neglect to give a direct access to their content. This hinders sharing of knowledge, because of the obligatory Apple’s iTunes application needed to access iTunesU.

The solution

Emulating the iTunes client: the script can be tested at[itunesU url]

It only needs the url which would open in iTunes and converts it to a displayable webpage.

For example for

Source download

index.groovy version 1 iTunesU xml to html groovy script

Why groovy?

Having experience with Java and Grails development using Groovy especially due to its powerful closures, xml navigation and html building was a obvious choice. Also this project started as a Google AppEngine prototype, but hit the no-user-agent change limitation.


Of the three types of layout used in iTunes U only the two column standard university page view and detailed course view (track list) are supported. The iTunes main site listing and main page three column layout is not supported.

Solution explained

iTunes uses a custom xml page to receive and render its content. This file can be access when switching the user-agent to “iTunes”.
Switching user agent is easy under Firefox with the user-agent switcher add-on
Part of the xml file

<FontStyleSet setName="basic22" normalStyle="helvetica22"
	linkStyle="link" linkPressedStyle="linkPressed" linkRolloverStyle="linkRollover" />
<FontStyleSet setName="normal40" normalStyle="lucida40"
	linkStyle="link" linkPressedStyle="linkPressed" linkRolloverStyle="linkRollover" />
<FontStyleSet setName="normal40Bold" normalStyle="lucida40Bold"
	linkStyle="link" linkPressedStyle="linkPressed" linkRolloverStyle="linkRollover" />
<MatrixView rightInset="0" bottomInset="0" leftInset="0"
	topInset="0" rowFormat="100%,*" viewName="Form">
	<View rightInset="0" bottomInset="0" leftInset="0" topInset="0"
		minWidth="948" minHeight="400">
			<!-- Layer 1 = Banner Image -->
			<!-- BEGIN ReplaceableImageXMLView -->
			<View alt="" height="400" width="600">
				<PictureView proportional="1" verticalAlignment="top"
					shouldBeVisible="true" shadowHeight="0"
					alt="MIT offers a selection of video and audio from several of our groundbreaking projects: MIT OpenCourseWare, MIT World, MIT TechTV, and Visualizing Cultures."
					shadowWidth="0" height="400" width="600"
					addShadowSizes="false" />
			<!-- END ReplaceableImageXMLView -->
			<!-- Layer 2 = link box area -->
			<MatrixView leftInset="0" rightInset="0" topInset="25"
					This ensures we leave enough room for the banner image in the 3
					column view
				<View minHeight="400" />
				<View />
				<VBoxView rightInset="25" bottomInset="0" leftInset="0"
						<VBoxView leftInset="0" rightInset="0" topInset="0"
							<!-- BEGIN description box-->
							<!-- END description box-->
							<!-- START ListBoxStack -->
								<FontStyle name="outlineTitleFontStyle" color="ffffff" />
								<FontStyle name="outlineTextFontStyle" color="ffffff" />
								<!-- BEGIN RoundedBox -->
								<View rightInset="0" bottomInset="0" leftInset="0"
									<Test value="7.0.0" comparison="greater or equal"
										property="iTunes version">
										<!-- BEGIN MaskedView -->
										<View rightInset="0" bottomInset="0" leftInset="0"
											<PictureButtonView rightInset="0" topInset="0"
												bottomInset="0" leftInset="0" alt="" color="rgba(0,0,0,0.75)"
												cap="4" />


The xml file is quite verbose and it takes some time to identify the interesting content.
The hard part of this project was to identify the right way to identify and select the wanted data from the xml tree.

Following are code snippets of the source file with their most important or interesting aspects explained.

First task of the script is to retrieve the xml page by settings the right user-agent [3] and then use the powerful groovy xml parser api [13] to have an easily navigable xml object.

def xml
def conn = new URL(handle).openConnection()
conn.setRequestProperty ( "User-Agent", "iTunes/8.1" )
def putBackTogether = new StringBuffer()
def r = new InputStreamReader ( conn.getInputStream(), "UTF-8" )
char [  ]  cb = new char [ 2048 ]
int amtRead = ( cb )
while  ( amtRead  >  0 )   {
	putBackTogether.append ( cb, 0, amtRead )
	amtRead = ( cb )
xml = putBackTogether.toString()
xml = new XmlSlurper().parseText(xml)

To work around default namespace bugs when recreating a xml string from an xml object the Markupbuilder has to be set to the apple namespace[6].

import groovy.xml.StreamingMarkupBuilder
def getXml(item){
	def outputBuilder = new StreamingMarkupBuilder()
	outputBuilder.encoding = "UTF-8"
	String result = outputBuilder.bind{
		mkp.yield item

Example of the powerful way to generate html code with the groovy MarkupBuilder.

import groovy.xml.StreamingMarkupBuilder
html.html(xmlns:"",lang:"en",'xml:lang':"en") {
	head {
		title xml.Path.PathElement.collect{it.'@displayName'}.join(" > ")
		meta('http-equiv':"X-UA-Compatible", content:"IE=8")
		meta('http-equiv':"content-type",content:"application/xhtml+xml; charset=UTF-8")

Identifying the type of layout the xml file is meant to build is done by looking at a reflection attribute from the first image found in the file.

def topimg = xml.'**'.find{ == "PictureView"}
def reflect = topimg?.'@reflection'==1 //true = course page

Getting page colors from FontStyle tags

def titleFontStyle = xml.'**'.find{ == "FontStyle" && it.'@name' == "normalTitleFontStyle"}?.'@color'
if(titleFontStyle == null){
	titleFontStyle = xml.'**'.find{ == "FontStyle" && it.'@name' == "outlineTitleFontStyle"}?.'@color'

Some more examples of the groovy MarkupBuilder: especially interesting is the mkp.yieldUnescaped [10] method to allow usage of html otherwise automatically converted symbols like &.

body(style:"background: #${xml.'*'.find{ it.'@backColor' != ''}.'@backColor'}"){
		div(class:"span-24 last nav"){
			def list = xml.Path.PathElement
			def last = list.size()-1
			list.eachWithIndex{ pe,i ->
				if(i == 0){
							mkp.yieldUnescaped "&nbsp;"
					a(class:"${i == last ? 'last' : ''}",href:"index.groovy?handle=${pe.text().trim()}", pe.'@displayName')

Being able to identify the right element is sometimes a bit tricky, especially that not all pages seem to follow the same structure rules.

	xml.ScrollView.View.MatrixView.View?.'**'.find{it?.name()== "VBoxView" && it?.parent()?.name()== "VBoxView" && it?.parent()?.parent()?.name()== "VBoxView" && it?.parent()?.parent()?.parent()?.name()== "VBoxView"}?.'*'.findAll{ it?.name() == "TextView"}.each{ text -> p text }
	mkp.yieldUnescaped "&nbsp;"

Usage of the xmlwise library[15] to parse the standard plist part of the xml containing the track list .

import xmlwise.*
div(class:"span-24 last tracklist"){
	table(cellspacing:"1", class:"tablesorter"){
				th ""
				th "Name"
				th "Time"
				th "Artist"
				th "Release Date"
				th ""
			def plist = Plist.fromXml(getXml(xml.TrackList.plist))
			plist.items.eachWithIndex{ track, i ->
				int seconds = (track["duration"] /1000)
				int minutes = seconds % 3600
				int hours = (seconds - minutes) / 3600
				seconds = minutes % 60
				minutes = (minutes - seconds) / 60
				tr(class:i % 2 == 0 ? "even" : "odd"){
					td track["rank"]
					td track["songName"]
					td ((hours > 0 ? String.format("%02d",hours)  + ":" : "")+ String.format("%02d",minutes) + ":" + String.format("%02d",seconds))
					td track["artistName"]
					td track["releaseDate"][0..9]
						a(href:track["previewURL"],rel:"lightbox[set 480 380]",title:track["songName"], "view")
						a(href:track["previewURL"],title:track["songName"], "download")

Resources used for html design

Google Chrome ADBlock without proxy

I found a new way to use the Google Chrome browser without having to install or use a proxy.

The solution is called

Since I use the developer preview channel, I installed adsweep as an extension/plugin.

Quick steps for Chrome-dev with adsweep extension:

  1. Switch chrome to dev channel with the Google Chrome Channel Changer (more info)
  2. Download AdSweep extension AdSweep.crx
  3. Install extension by running chrome from command-line with:
  4. chrome.exe –install-extension=AdSweep.crx

    Chrome is installed by default in your application data profile: for Vista users:

  5. Enable extensions by adding:
    to your Google Chrome Shortcut
  6. Verify that the extension/addon loaded correctly by navigating to chrome-ui://extensions/

Happy browsing, without Ads and proxy!

Google Chrome AdBlock with Privoxy

[update 2]

Check adsweep an adblock extension for chrome

other alternatives to my original solution:

Privoxy solution:

I love the new Google Chrome Browser, especially the…:

  • – really fast render speed,
  • – new tab page
  • – and the ability to create a new window from a tab that you drop outside chrome.

Naturally, I am missing all my nice add-ons from Firefox, mainly the adblock add-on!

So I found an alternative solution: using Privoxy. Privoxy is a small web proxy that runs locally and has the ability to filter ads.

  • 1. Download & install
  • 2. And then set Google chrome’s proxy options:
    Options->Under the hood->change proxy settings->Lan Settings
    Check: “Use a proxy server for your LAN”
    And under advanced add proxy address port 8118 for http and secure but leave ftp blank.

Now you can surf the web with Google Chrome and a lot less ads!

Make Thunderbird Usefull [list of add-ons]

Here is the list of add-ons I use to make my Mozilla Thunderbird Mail client more usefull.

New Features

  • Folder Account
    Lets you associate user accounts and identities with specific folders.
  • Remember Mismatched Domains
    Adds a “Don’t warn me again about this certificate for this domain” checkbox to the Domain Mismatch and Expired Certificate warning windows.
  • MinimizeToTray
    Minimizes Thunderbird windows into the system tray.
  • MoreFunctionsForAddressBook
    gives the possibility to import and export in vCard and vcf format;
  • Sync Kolab 1.0.1
    SyncKolab reads a selected Imap folder and synchronizes it with the local address book and calendar
  • WebMail
    Integrates web site based email accounts in to Mozllia Thunderbird: Yahoo, Gmail, Hotmail,…



Mozilla Thunderbird Crash (Solved)

Suddenly Mozilla Thunderbird started crashing on me. I found out that it was the webmail addon “Hotmail 1.2.15 (live)” which creates the problem. The solution is to upgrade to the newer version 1.2.17, but unfortunately this has to be done manually:

  • 1) download the new version of the addon (right-click save as).
  • 2) start mozilla thunderbird in safemode.
  • 3) drag & drop the downloaded extension into the addon manager.
  • 4) restart Thunderbird.

Slowness with localhost on Vista and seaside/squeak in firefox

While testing seaside when loading the pages locally in firefox I had a long delay. After some digging,

it turns out that the slowness is caused by an IPv6 issue with DNS and can easily be resolved by turning IPv6 support off in Firefox while doing localhost testing. To make the change, type about:config in the address bar, locate the network.dns.disableIPv6 setting and double-click on it to set it to true. This does the trick for the Firefox localhost issue on Vista and everything is running fast again.

as it turns out other people had the same issues but not in relation with seaside, therefore I found it in google only after having discovered the solution by myself.

I am hopping that blogging it under seaside/squeak will help someone save some time.