papadi Development Blog

I run into an (one year) old article of Udi Dahan today. He explains how REST can be used to scale up an application, of course without the need to add additional hardware.

The idea is simple. If you have a SOAP web service that thousants of clients call, then a common practice would be to add caching behind it, in order to avoid hitting your database (or other resources) for each request. Common and cheap practice that works up to some extend.

However, If you use REST instead of SOAP for your service, then your responses are simple HTTP responses. Therefor you can add some HTTP headers in them, forcing the intermediates of the communication (proxy servers for example) to cache the response themselves. The result would be that when the client tries to hit your server, intermediate servers will return the cached response instead of hitting your server. Nice!!!

Read the article...

I'm trying to find my way into the Silverlight world lately. And one of the most predominant phrases in this world is Model-View-ViewModel pattern or else MVVM. This good old pattern suggests the separation of concerns in the UI tier into the three distinctive layers it's name indicates. I've never dealt with MVVM before and as I said Silverlight is also new to me. Therefore I'm trying to read as much as I can before digging into the code.

The most enlightening article I've read so far is Kathleen Dollard's "Applying Model-View-View Model in Silverlight". Kathleen explains how MVVM can be helpful, how to apply it in Silverlight, but also which MVVM promises can be elusive and which not!

Another article I read during my vacations was Shawn Wildermuth's.

For Silverlight 2 starters I recommend this free tutorial from silverlight.net:

http://silverlight.net/learn/tutorials.aspx

There is code available both in C# and VB.

Στο site isvinnovation.com (isv=Independent Software Vendor) της Microsoft είδα ότι θα γίνει μια νέα σειρά δωρεάν webinars (ιστο-σεμιναρίων αν μου επιτρέπετε!) με θέμα το Silverlight 2. Η σειρά θα γίνει από 15 Σεπτεμβρίου έως 20 Οκτωβρίου, ενώ για όσους δεν θα μπορέσουν να την παρακολουθήσουν ζωντανά θα είναι διαθέσιμη και on-demand. Η ώρα που θα γίνονται τα σεμινάρια είναι 18:00 (ώρα Ελλάδας).

Περισσότερα εδώ.

Υπάρχει και αυτό το rss feed αν σας ενδιαφέρουν ανάλογα σεμινάρια.

Πήρατε μήπως είδηση τα comics του Heroes Happen Here;

Κάντε κλικ εδώ...

Πολύ ωραία απλή εφαρμογή σε silverlight, ωραία γραφικά στα comics.

Αλλά από περιεχόμενο, αν εξαιρέσεις την πρώτη σελίδα, δεν φτάνει με τίποτα τον Ζαχαρία μας!

In general, I'm a great fun of DotNetNuke, the free, Open Source Framework for creating web portals. It is very powerful and easy to use. However it is full of bugs! Yes, it is.

Most probably this is because the DNN team releases a new version once every couple of months! No to mention the intermediate releases of specific modules. You don't have to take my word for it. See the downloads page of the project. From January of 2007 there have been 5 releases! That is one release every 37 days!

Currently, in my web site, I'm using version 4.5.1. I had several problems before that and I spend lot's of hours trying to figure out what to do. There where times that I was completely helpless. I was thinking of throwing everything away and republishing my web site using a different framework. Here is the list of my posts in the dotnetnuke forums. Finally I installed version 4.5.1, I spent a couple of days playing with the configuration it seemed that I was there!

For months my web site was doing fine! And of course I decided not to upgrade DNN to any new version, no matter what! And suddenly!!! I click on 'Add blog entry' to write something in my blog and I get a 'DotNetNuke. Services. Exceptions. ModuleLoadException: The server tag is not well formed' error! What was it? A patch recently released by Microsoft revealed a bug of DNN. There was an invalid character in EditEntry.ascx file of blog module. Here is more by DNN team member Antonio Chagoury.

Do the following mean anything to you?

• Is your IIS full of test web projects that you once created and you keep them... just in case?
• Do you have old projects that you want to look once in a while but you don't have the time to create virtual directories for them?
• Do you have dozens of databases on your SQL Server for all that projects?
• Do you find the procedure of copying files, IIS settings and SQL Server database to create a copy of a web site tedious?
• Would you like your web sites to be easily portable by simple copying their content files, without IIS and SQL Server configurations?

If these sound familiar... here is your solution!

How to start a web site without IIS

You can use the ASP.NET virtual web server to start a web site without using the IIS. It's the same tool that opens when you create a web site under the file system from the Visual Studio. The usage is simple:

How to access a database without permanently attaching it to SQL Server

One great feature of SQL Server 2005 Express is the ability to dynamically attach a database to server by using the connection string. This way your database is attached when your application starts and is not permanetely connected to sql server using a standard file path, something that would make it difficult to move or copy. In the attached sample you can see one database configured to work this way. The database is placed under the App_Data folder of this web site and it's location is set in the connection string (see web.config) :
   

Sample

The attached sample assumes that .NET Framework 2 and SQL Server 2005 Express are installed on your machine.
Download the attached file, unzip it and double click StartVirtual.bat. An icon will show up in your windows tray area (right lower corner). Right click on that icon and then select 'Open in Web Browser'.... and here it is! The web site runs without IIS, without Visual Studio and without previously attaching the database to sql server.
Try making copies of this web site and starting different instances. Be sure to first edit the StartVirtual.bat and change the port number for each instance, if you want them to work simultaneously.

Click here to download:

PortableWebTest._zip (172 KB)

I'm glad to see my first implementation of DotNetNuke (DNN 3 beta), an open-source portal system. My implementation concerns the Ski Centre of Falakro (Drama-Greece) and you can find it in address www.skifalakro.gr. I haven't done much customization to DNN yet, except modifying the default skin and adding a simple custom module which shows weather info.