The project was about automatically finding invariants in web applications. The first focus was finding invariants in the JavaScript parts, but later on we extended the scope a bit and also included invariants over the DOM. While most of the techniques I developed can be used in a very generic way, my implementation depends on Crawljax. I developed plugins to Crawljax, under the name of InvarScope, that can automatically find these invariants and use them for regression testing.

We submitted a paper based on my work to ICSE’11, so before that was finished I was not allowed to blog or publish any of my work. Well, we made the deadline, so I can now release all of the code, my thesis and the paper itself.

The code I wrote is available in a subdirectory of the Crawljax plugins Google code project. We’re currently in the process of fixing all Maven dependencies, cleaning up some code and making it all work with the current Crawljax trunk version, so expect a binary release in a few days.

Don’t hesitate to contact me if you have any questions!

My colleague decided to try out ExpressionEngine. He bought the freelancer edition and he’s been trying things out. Up until now, it all seems to work quite well, although the back-end can still be too complicated for our clients. Also, I hate the fact that you should pay 300 dollars to use ExpressionEngine for a commercial company. Thats an added fee some customers would rather spend on different things.

So, I started to search for open-source CMSes myself and made a list of requirements.

• It should not be page based, it should allow you to model your own content. If you use a CMS that supports types/entities/resources/sections/whatever you can create your own page type, but you can also create more advanced things like portfolio items, projects or products (yes, even a simple web shop is possible then).
• The back-end should be as simple as possible.
• It should be written in PHP, object-oriented if possible, and use MySQL for storage.
• There should be a good, flexible templating engine for the views.
• It should have a good plugin API.

Well, using this list it was a lot easier to search for the most fitting CMS, as quite a lot CMSes are only page or post based. The list of possible candidates shrunk by more than 75%. Eventually I found a CMS I had never heard of, but which seemed to have all the things we were looking for: Symphony CMS.

I’ve been trying it out in the last few days and I still haven’t found any deal-breakers. Symphony CMS has a great website, friendly community (because it’s still small I think), great features, simple back-end, small code-base and it can be easily extended by writing extensions.

Some things might give problems for specific clients though: multi file upload is non-existant (there’s one extension that doesn’t do what it should) and the WYSIWYG editor extensions, with support for placing images etc., don’t seem to be integrated well enough with Symphony CMS yet. Well, maybe I’ll just fix those two myself and contribute them upstream. That is, if I have some spare time…

Well, finally there is a solution. It’s called SparkleShare and it’s completely open source and uses Git as a backend. Today they released a very early alpha version and I tried it out immediately. After having some trouble with the interface (you need to insert <username>/<reponame> in the folder input box if you use Github), everything worked great. However, I don’t advice anybody to use it in production. It’s still in development and can contain serious bugs. I can’t wait till it gets more mature and ready for production usage!

Getting the tablet to work in Karmic is a little bit more work. Most steps are the same, but the actual installation requires more than just copying the kernel module: you also need a new fdi file for hal and you need a new Xorg driver. For completeness, there are all the commands you need to execute.

First, install some compiling tools and header files:
sudo apt-get install build-essential libx11-dev libxi-dev x11proto-input-dev xserver-xorg-dev tk8.4-dev tcl8.4-dev libncurses5-dev

Next, download the latest linuxwacom driver (0.8.6 at the moment of writing):
wget http://prdownloads.sourceforge.net/linuxwacom/linuxwacom-0.8.6.tar.bz2

Now unpack, configure compile and install it:
tar -xf linuxwacom-0.8.6.tar.bz2
cd linuxwacom-0.8.6
./configure --enable-wacom
make
# I know 2.6.30 is the wrong number, but it's the highest available and it works just fine
sudo cp src/2.6.30/wacom.ko /lib/modules/`uname -r`/kernel/drivers/input/tablet/
sudo cp src/util/10-linuxwacom.fdi /usr/share/hal/fdi/policy/20thirdparty/10-linuxwacom.fdi
sudo cp src/xdrv/wacom_drv.so /usr/lib/xorg/modules/input/wacom_drv.so

Now restart hal, reload the wacom module and plug in your tablet:
sudo /etc/init.d/hal restart
sudo rmmod wacom
sudo modprobe wacom

The tablet should work now. You can also add the module name to /etc/modules to automatically load it on boot. Same issues as in the previous post apply to Karmic, but for me this works good enough.

Update

It seems that since I published this post four months ago, it helped a lot of people. At that time I couldn’t find a DKMS script that would automatically compile and install the newer module after every kernel upgrade. Also, I didn’t have the time to do it myself. Well, things have changed. After Brett Alton posted his update to my post. Martin Owens replied to his post with a link to a PPA that contains the newer module with a DKMS script. So please, use this PPA and save yourself a lot of trouble! The instructions are really simple, just run this in a terminal:

sudo add-apt-repository ppa:doctormo/wacom-plus
sudo apt-get update
sudo apt-get install wacom-dkms

Don’t forget to register your tablet at the Wacom website, because you can specify Linux as your operating system. We might get even better support if a lot of people do this.

Old post:

First, install some compiling tools and header files:
sudo apt-get install build-essential libx11-dev libxi-dev x11proto-input-dev xserver-xorg-dev tk8.4-dev tcl8.4-dev libncurses5-dev

Next, download the latest linuxwacom driver (0.8.6 at the moment of writing):
wget http://prdownloads.sourceforge.net/linuxwacom/linuxwacom-0.8.6.tar.bz2

Now unpack, configure compile and install it:
tar -xf linuxwacom-0.8.6.tar.bz2
cd linuxwacom-0.8.6
./configure --enable-wacom
cd src/2.6.30/ # I know this is the wrong version, but it's the highest available and it works
make
sudo cp wacom.ko /lib/modules/`uname -r`/kernel/drivers/input/tablet/
sudo rmmod wacom
sudo modprobe wacom

The tablet should work now. You can also add the module name to /etc/modules to automatically load it on boot. There still one issue left for me. In Mac OS X I can use the whole tablet, i.e. the right corner is the right screen corner. In Lucid however the grey lines indicate the screen borders, so the right corner of the gray lines is the right screen corner. This means part of the tablet is not used and this can be quite annoying if you’re used to the previous behavior.

Don’t forget to register your tablet at the Wacom website, because you can specify Linux as your operating system. We might get even better support if a lot of people do this.

Years ago I used one password for all my accounts. These days, a lot of services didn’t require user accounts, so I was actually using my password only for a hand full of services. When the number of account-required-services started to grow, it occured to me how insecure it is to only use one (easy to guess) password for so many different services. So I started to think how to make it more secure. The first technique I used is simple but very secure:

• Think of a sentence, preferably a question or statement with punctuation characters. Now take the first letter and all these punctuation characters. This will be your password.

For example, How can I remember a difficult password? Like this!, will give you the password HcIradp?Lt! If you just remember that sentence, you have a very secure, long password that nobody can guess. This techniques has been known for quite some time and is recommended by security experts as well.

A few months later I had numerous different sentences to remember. This started to become a daunting task as well. So I came up with another technique:

• Add some letters of the service in question to your password seperated by some special character like the pipe character.

This means that you can have one master password that includes a number of letters as a kind of salt. Every service will have a different password, but you can easily remember it. How is this done for the example password? Well, something like this might be an option:

Gmail password: gm|HcIradp?Lt!
Flickr password: fl|HcIradp?Lt!

Now that’s easy to remember right? These first few characters can also be found in the URLs of these services, so that makes it even easier. Now hurry up and fix those insecure passwords, but remember, a security question has to be very secure as well, because a lot of people might know your birthcity and it will make your password completely useless.

Furthermore, Adam Rosenberg of Center for Democracy & Technology (CDT) asked us to write a guest blog post. Of course we were interested in doing so, because it gave us another opportunity to make people aware of the potential problems of sharing your location with the whole world. The post was pusblished today and can be read on the CDT website.

Don’t get me wrong, I love the whole location-aware thing. The information is very interesting and can be used to create some pretty awesome applications. However, the way in which people are stimulated to participate in sharing this information, is less awesome. Services like Foresquare allow you to fulfill some primeval urge to colonize the planet. A part of that is letting everyone know you own that specific spot. You get to tell where you are and if you’re there first, it’s yours. O, and of course there’s badges..

Foursquare

The danger is publicly telling people where you are. This is because it leaves one place you’re definitely not… home. So here we are; on one end we’re leaving lights on when we’re going on a holiday, and on the other  we’re telling everybody on the internet we’re not home. It gets even worse if you have “friends” who want to colonize your house. That means they have to enter your address, to tell everyone where they are. Your address.. on the internet.. Now you know what to do when people reach for their phone as soon as they enter your home. That’s right, slap them across the face.

To raise some awareness on this issue and emphasize how easy it is to retrieve this information let me introduce: http://www.pleaserobme.com. Have fun and please don’t hook up Foursquare to your Twitter account, okay?

Download Crawljax now and give it a try!

To get a better grasp of what is possible, have a look at the Google Tech Talk a colleague of mine did: