Chorn Sokun’s Weblog

felt bore today and decided to tune into studio and record some stuff :D hope you enjoy it.

I know, I know the quality is bad but I don’t know I am not do much with youtube so it the luck I get :) BUT as always orginal video can be download here.

Source code: http://storm-the-castle.googlecode.com/svn/tags/barcamppp

By default you can intercept unexpected exceptional error occur in MonoRail you can opt to render a specific view from Views/Rescues folder or let MR pick standard one such as 404 page not found …

How how about you want to log the exception then you need to build a custom controller class that implement IRescueController interface just like this:

public class RuntimeExceptionController : SmartDispatcherController, IRescueController
{
  public void Rescue(Exception exception, IController controller, IControllerContext controllerContext)
  {
    // ... log via log4net ...
    // ... render & send error back home :) whatever you find helpful
  }
}

// usage: simple
[Rescue(typeof(RuntimeExceptionController))]
public class HomeController: SmartDispatcherController{
  public void Index(){
     throw new Exception("Boom !");
  }
}

Localization in .NET doesn’t seem to solve a lot of problem in theory but I get no luck to get it work, although I built a custom Culture and having the resource file embedded in the assembly it just WON’T WORK !

After look around for solution I decided to give up and cheat a bit building localization engine from scratch is not too difficult but I tend not to spend my time on this yet.

So here is my way to have bilingual UI (Khmer & English)

by faking treat fr-FR == km-KH and that work !

Never die with your tool, exercise your brain ;)

Simple scenario each time a province change, district, commune & village will reset, not a big deal for me now a day to have this scenario on the web application but hey look it WinForm :( let see

I started from Form Load event cbProvince combobox get binded then wire cbProvince with SelectedIndexChanged event handler to load list of district into cbDistrict combobox and so on the code look more or less like this

public void Form_Load(object sender, System.EventArgs e){
  // binding cbProvince
}

public void cbProvince_SelectedIndexChanged(object sender, EventArgs e){
  //... binding the cbDistrict ComboBox using current selected value from cbProvince
}

public void cbDistrict_SelectedIndexChanged(object sender, EventArgs e){
  //... binding the cbCommune ComboBox using current selected value from cbDistrict
}

Sound good all event wired hit F5 to try out. Guess what happen? it slow & AND finally throw an exception !!! but how? years passed and this behavior didn’t change a bit

// flag state
private bool formReady = false;
public void Form_Load(object sender, System.EventArgs e){
  // binding cbProvince
  formReady = true;
}

public void cbProvince_SelectedIndexChanged(object sender, EventArgs e){
  if(!formReady) return; // this is the trick don't fire the event
  formReady = false;
  //... binding the cbDistrict ComboBox using current selected value from cbProvince
  formReady = true;
}
public void cbDistrict_SelectedIndexChanged(object sender, EventArgs e){
  if(!formReady) return; // this is the trick don't fire the event
  formReady = false;
  //... binding the cbCommune ComboBox using current selected value from cbDistrict
  formReady = true;
}

I call out for an excuse for not practicing PHP enough recent year; with just a simple date_diff could knock me out :) not to open my complain of having different version of PHP to check before using a function(s) I got a request from a friend to help workout how many days from two given date.

Now if I have two date string (it is what we get from form post right?)

// fixed format as I don't want to deal with complicate of different world format :(
$day1 = "26/03/2009";
$day2 = "28/03/2009";
// now I need to know how many days does it take from day1 to day2
// PHP 4.x; ignore my out of date PHP skill this is how I did it
$break_day1_apart = explode('/', $day1);
$break_day2_apart = explode('/', $day2);
$day1_number_form = $break_day1_apart[2].$break_day1_apart[1].$break_day1_apart[0];
$day2_number_form = $break_day2_apart[2].$break_day2_apart[1].$break_day2_apart[0];

$day_diff = abs((int)$day2_number_form - (int)$day1_number_form);

// and it should work by theory
echo $day_diff; 

Suck ! what would you do instead?

When Ayende typed Guard.Against(condition, error_message) it clicked in my brain. I thought wow that was nice and easy to use what it does was check if the condition is true it will throw and exception with error message specify. I had an idea using this litle beast for business validation, since it doesn’t required any special configuration all you have to do is adding reference to Rhino.Common.Clr.dll.

However the original Guard API only has only two static method Guard.Against() it was limited for web application. In web application we might want to report back all problems so user can make the correction before they re-submit the form again, but using Guard.Against() we only catch one problem at a time, if we have multiple codition to check you can imagine how annoy for web experience.

Ayende is kindly enough accepting my patch for two additional method for the Guard bellow:

• Guard.Check(condition, error_message) – same behavior as Guard.Against() but it won’t throw and exception instead keeping records of problems
• Guard.Report() – until .Report() get call and exception known as GuardSpotException will be throw.

Let see how I can improve my usage experience with these methods

try{
  new Guard()
    .Check(pay.Date.Equals(DateTime.MinValue), "Invalid payment date.")
    .Check(pay.Amount == 0, "Invalid amount, should it be something other than zero?")
    .Report();

  // persist pay instance to the database
}
catch(GuardSpotException ex)
{
  // list of errors message
  PropertyBag["errors"] = ex.GetErrorSummary();
}

First I instantiate a new Guard object and start checking conditions (business rules) finally I call Guard.Report() if there is any true condition (= business rule voilated) and exception known as GuardSpotException will be throw you then can catch and examin all problems.

Isn’t that cool?

I hope Ayende won’t mind if I steal the name :D well, he did used that name for one of his sample project. Anyway let me throw some good news out to all of my blog trackers “who loves coding :D” I just check-in a sample project using Castle minutes ago.

As I am not sure how many of you understand what I am blogging about or even had trouble try to replicate my trip. Now I make it simpler if you want to catch-up or debate with me on my future Castle posts you got a chance to start it  now just go grab a stick and stone from http://code.google.com/p/storm-the-castle/

If you have any question/suggestion/request you can post it on the project site I am happy to help it out as time allow ;)

Oh by the way this is my 100 posts :))

Happy Chinese New Year everyone.

It amazes to see how people taking their value time and energy try to make the different, somehow I was not expected this phenomenon to growth that much in Cambodia but the truth is Cambodian make a different.

Ladies & Gentlemen, Boys & Girls watch out !

Syntax Localization

At the movement of posting I am not clear who behind this project… but, you guy made something that turn my morning into

Congratulation! now let open our discussion will this thing change Cambodian development climate what are your pros & cons?

I never regret to step my feet into programming world back in 1997. My first experience using notepad to script out (HTML) website. I don’t remember how many times I skew up my brother’s computer just to figure out a thing no matter how hard he try to avoid me. 

Rewind for the last 10 years I keep pushing myself up step by step no matter how hard, stressful I got I never give up. 10 years? Yeah I know my brain deserved a major upgrade perhap replacement of RAM, CPU Squad Core or something :) But see it took me so long to get to this stage where I legendary programmers abroad take much shorter time to advance their skills.

You may compare my learning experience to a single pig raising in a big farm, the lack of physical interaction, challenge and guiding is the main source preventing it from fast growth. But that are all history today I am so happy, because I am no fall into those mind set and I am not alone, ladies & gentlemen the dark army is rising. 

Dark Army, taking on TDD & DDD

This is the 5th session that they all come together and learn .NET programming C# and I glad to become their instructor as much as I enjoy walking them through the learning curve. Although it is a programming course we don’t talk much about syntax sugar or debate about how it was designed because it doesn’t give much value in real world once it’s time to get down to business so what they need to learn are concepts and tool set for rapid application development.

I want to see some new face as well but it doesn’t seem to work out just yet :) but again we please to invite you to join our journey anytime just keep you eyes on our public calendar.

Let the spirit of sharing growth among Cambodian, let us all create an opportunity for our young generation to extend what we had discovered.