Adam Sobaniec

I had an opportunity to work on a project with BDD technique (link) and I must say that I've really enjoyed it. It requires more time to be spent on the development process, however, since the overall quality of the software gets better - it's definitely a good choice.

While working with BDD I used to implement automatic acceptance tests with a scenarios defined in Gherkin language. Tests have been written in xUnit and Watin which is a pair that is highly recommended across many .NET related web sites.

After performing couple of test runs, one thought came into my mind - is it possible to run them in such way that they will not only perform as automatic acceptance tests but also as a performance tests? Why not write an application that will take all these already written tests and spawn them in such way that there will be plenty of them running in parallel. Since each Gherkin scenario corresponds to a single user action, such operation would allow to check how web application behaves under heavy load.

I have started a research on how such functionality may be achieved and found that unfortunately Watin is not a proper tool to be parallelized. Since it uses the system installed IE to run it's impossible to simulate many different users operating simultaneously. For example, IE shares cookies among many processes so there is only one single session that can be stored.

I have started looking for something similar to Watin (in .NET) but allowing to run independent tests in parallel. Unfortunately I haven't found such tool. Right now I have ended with an idea of writing an application that will allow to write custom automatic UI tests and as well, run performance test basing on implemented earlier scenarios. The only problem is that the most important part of an application that is currently held by Watin, should be written from scratch in order to run fast and stable in parallel...

I know that there are probably many not .NET related tools that allow to perform automatic and performance tests (Sahi?), but in my opinion it would be much better to have, for instance, advanced Visual Studio add-on that will hold all BDD related stuff with all tests and scenarios defined in C# ;)

Finally, after a couple of hours of coding and testing I've released the logging tool that in my opinion can be used for 90% of .NET database driven application. My main aim was to create a tool that will be extremely simple to use, and won't need tons of XML configuration. I hate when the web.config or app.config files become too large - It may lead to very confusing bugs, especially when you have to deal with many environments with different configuration settings.

I wanted to make a tool that keeps logs in the database and to provide easy integration with Windows Azure cloud. I have also created a log viewer - QLogBrowser, that allows to read logs and performance entries without the need to perform any SQL queries.

You can read more and download the QLog on the projects tab. Feel free to send me any feedback.

As I Have mentioned in my previous post the next step to localize ASP.NET MVC 3 application is to set up a config file for razor views. To do this you need to open a web.config file placed under the Views folder (not the main web.config file!)

There, under the "system.web.webPages.Razor" section you have to modify the value of the "pageBaseType" attribute of the "pages" element:

<pages pageBaseType="System.Web.Mvc.WebViewPage">

And change it to the class that we have created (BaseWebViewPage under the LocalizationSample.Domain.Libs namespace):

<pages pageBaseType="LocalizationSample.Domain.Libs.BaseWebViewPage">

    public abstract class BaseWebViewPage : WebViewPage
    {
        public string GetString(string key)
        {
            ELanguage language = (ELanguage)Session["Language"];
            ResourceService resourceService = new ResourceService();
            return resourceService.GetStringResource(language, key);
        }

        public string GetString(string key, params object[] args)
        {
            ELanguage language = (ELanguage)Session["Language"];
            ResourceService resourceService = new ResourceService();
            return resourceService.GetStringResource(language, key, args);
        }
    }

You will need to add a System.Web reference to the LocalizationSample.Domain project. As you can see this method initializes a new instance of a ResourceService and basing on the current language of a user it retrieves the needed string from the proper resources. Now let's take a look at this sample code from _Layout.cshtml (Layout page automatically derives from BaseWebViewPage too!):

    <div id="container">
        <h1 class="header">
            @GetString("SampleLocalization")
        </h1>
        <div class="language-picker">
            <a href="/Home/SwitchLanguage?lang=pl">@GetString("Polish")</a>
            <a href="/Home/SwitchLanguage?lang=en">@GetString("English")</a>
        </div>
        <div id="content">
            @RenderBody()
        </div>
    </div>

As you can see usage is very simple and doesn't affect readability of the Razor code. There are few other things that should be implemented, like LanguageFilter (to setup Session["Language"] variable), UserService (to determine the default language of the user). Instead of providing here quite a big amount of code I've uploaded my project that I've used to write this tutorial.

In my opinion this method of localization gives more control over the localization process and once implemented it allows to easily scale to the new requirements. For example there may be a need to get the localized images - it can be done easily by implementing a method GetImage() for a BaseWebViewPage that provides html "img" tag with "src" attribute that points to the localized image.

Since I didn't observe much traffic on my site I've focused on my master's thesis instead of writing new entries on my blog. However during past few days I've noticed an increase in the number of visitors on my site so I've considered it as a good reason to finish the article on localizing an ASP.NET MVC application :)

I've also updated my technologies site. I've added Watin and switched nUnit to xUnit.

Watin is a great tool to test web applications UI. I've just started to learn it (in my opinion better than Sahi or anything else, mainly because I can write tests in C#). I really like the idea of writing the scenarios for an application and applying test for each scenario. That way with each update of a source code one can be sure that nothing got broken. I've found it when I was reading about BDD - Behaviour Driven Development which is also a very interesting topic. I hope that soon I will be able to write some nice articles about Watin and the concepts of BDD ;)

Concerning xUnit - I've really liked it's idea of simplicity, therefore I've given it a try and really liked it. When I won't have a possibility to use Visual Studio integrated test tools I'm pretty sure I will use it as my main tool for unit testing.

Now, coming back to alternative method of localizing an ASP.NET MVC 3 application. As I've mentioned in my first post the core part in this method is to introduce new base class for each web page, let's call it BaseWebViewPage and add it to the project under LocalizationSample.Domain.Libs namespace. Each view page in the Razor view engine needs to inherit from an abstract class, so we need to apply "abstract" keyword to our newly created class. What more - it needs to have a generic type parameter (for a Model of course!) and to inherit from a WebViewPage<T> class. You will need to add a reference to the System.Web.Mvc and System.Web.Webpages in order to find WebViewPage class (UPDATE: you also need to add a reference to the System.Web in order to be able to operate on a Session property). Finally it should look as follows:

namespace LocalizationSample.Domain.Libs
{
    public abstract class BaseWebViewPage<T> : WebViewPage<T>
    {

    }
}

As I've mentioned in my previous post - this class will contain a method GetString(string key) that will retrieve a resource string that is being hold under the given key. Basing on the current language of a user proper resource will be selected.

I will present this method and how to set up web.config file to force all view pages to inherit from our newly created base class in my next post. That will be the part 3 - the last one ;)

Localization is a common problem for many applications. When I was coding in ASP.NET MVC 2 I used to operate on global and local resources and GetGlobalResourceObject()/GetLocalResourceObject() methods within a view to retrieve the string that I wanted to present to the user. At the beginning of the view code I was setting the UICulture page property basing on the session variable that stored information about user language.

In ASP.NET MVC 3 there is no access to this methods within a view so there is a need to change the culture of a given thread basing on the current language of an user and then use strong typing of a resource to retrieve the desired content.

Personally, I don't like this method. In my opinion switching thread culture is not a best option for an enterprise system. For example Decimal.Parse() method uses current thread culture to identify the decimal separator symbol. In one culture "," (comma) is going to be a decimal separator in other it will be a thousands separator symbol. There might be also other culture specific problems that will show up especially when using the background worker task that is being run in a separated thread (like Azure Worker Role).

I want to present a different solution that may look complex, but once implemented it will work with 100% efficiency for any problem.

First of all I need to achieve such point where at any point in the given Razor page i will be able to use a code like:

    <div class="sample-div">
        @GetString("SampleString")
    </div>

GetString() will retrieve the language of an user basing on the variable "Language" stored in a session and retrieve desired resource that is placed under the "SampleString" key. The variable "Language" is an enum of two characters that describe the language of a current user like "en", "pl" etc. It's an ISO 3166-1 alpha-2 country code.

Let's say that we want to make our application available in two languages - english and polish. First, create an empty ASP.NET MVC 3 project "SampleLocalization". Application will follow the concepts presented by me in earlier posts. For this reason there will be a service layer implemented. Repository layer will be omitted since there is no need to retrieve data from any external source. To present the whole concept of an architecture mentioned in the post #3 I should create an abstract layer for a services and use an IoC container (like Ninject) to inject dependencies. But since I want to focus on a localization I will simplify this project.

The general structure of a project should look as follows:

As you can see there is SampleLocalization.Domain project created. It's good to split all business related classes to the separated library so that it's easily accessible by other application modules. Of course for this project there won't be any additional modules, but anyway it's a good habit.

The content of a localization is placed in the SampleLocalization.Domain.Localization namespace. The enum ELanguage presents the language that is selected by an user. The code looks as follows:

    public enum ELanguage
    {
        En,
        Pl
    }

There are also two service classes: UserService and ResourceService. First one will be used to determine the default language of an user and it's going to be used by the LanguageFilter. LanguageFilter is a global action filter that will check whether the session variable Session["Language"] is set. If not it will set the default language for a user basing on the configuration file. However, there may be implemented a method that will determine the default language for a user basing on his IP address, or http language specific headers.

The ResourceService class will be responsible for retrieving the content from a specific resource basing on the language specified.

What's missing in this structure is a base class for a Razor page that will contain the method GetString() and use the ResourceService to retrieve the localized content. It will be presented in a part 2. Stay tuned.

I've started writing an article about ASP.NET MVC 3 application localization and got stuck on syntax highlighting for code samples. I've used Syntaxhighlighter for code samples, but the C# code was presented there in an odd way. I've tried to configure it but with no results.

After that I've tried a google prettify, which is widely used in many websites. I had to modify few CSS rules to make it working, but the results, still, didn't satisfy me.

Finally, after some time, I've found a Sunlight syntax highlighter, and this script is in my opinion the best choice. It fits C# very well. Just take a look at code samples from previous posts.

Link to the Sunlight syntax highlighter website can be found in the links section.

Article about localization is coming soon :)

Designing a proper architecture of a database-driven application is not an easy task. I have tried many architecture concepts but I've never been fully satisified. When it comes to write an application from scratch it's not a big deal if a design is bad, because you don't have to worry about deep modifications in a code. But when a customer changes his mind, or the application is growing then suddenly appears a need to modify it - if you have a wrong architecture it will require a lot of work to adapt to the new requirements (not to mention bugs that happen when applying such modifications).

When I've started writing web applications I used to write so called "spaghetti code". This was long time ago, when I was learning PHP. It was terrible. It required a lot of job to modify the code, there were a lot of code repetitions etc. I knew that I need to change it somehow. So I have learned CakePHP - very good MVC framework, which forced a programmer to apply a proper architecture. When I've switched to the ASP.NET MVC, I've realized that M letter is a very general concept here, and that there are many ways to design a business layer.

I've started by writing a general Model layer, which was responsible for all business related operations. For example, when I had a "clients" table in a database then I had created ClientModel class, which was responsible for all operations on a "clients" table. Unfortunately it wasn't a good choice. Given class contained a huge amount of code and was really difficult to manage. After that i had tried many other options of an application design, but still with no luck.

Finally, after reading couple of blogs, i have found the architecture that, in my opinion, is a best choice for many data driven applications. The core concept is so called service layer and repository layer. Take a look at the following diagram:

Follow the directions to see step-by-step through which layer the flow of an application is being realized.

Controller layer has a direct access only to the service layer. The repository layer is hidden for it. Only service classes have an access to the repositories. Same rule applies to the ORM layer (which is optional). Only repositiories have access to it. Models and ViewModels, are plain POCO classes that are used to transfer informations between layers. What is the difference between them? Models are exact mappings of a tables in a database. For example if we have a "clients" table, then we will have a POCO class that represents a single client:

    namespace SampleApplication.Models
    {
        public class Client
        {
            public int Id { get; set; }
            public string FirstName { get; set; }
            public string LastName { get; set; }
            public List<Item> ItemsBought { get; set; }
        }
    }

It's an example of a model that represents table "Clients" with columns "Id", "FirstName", "LastName" and is referenced in a One-To-Many related table "Items" (each item belongs to one client). What about a ViewModel?

ViewModels are the extension of models. Let's say that we want to provide a user with some sort of statistics about clients. We have to create another class (in ViewModel space) that will contain a total number of clients, total amount of money they have spent etc.:

    namespace SampleApplication.ViewModels
    {
        public class ClientStatistics
        {
            public int TotalItemsBought { get; set; }
            public int TotalMoneySpent { get; set; }
            public List<Client> Clients { get; set; }
        }
    }

It's a plain class that represents statistics about clients. Models and ViewModels are being transfered through layers, and modified by them if necessary. Finally they are pushed into a View layer and presented to the user.

I have created a sample project to demonstrate this architecture

The project is absolutely basic. I have created there an abstract layer for services and repositories, but since there are no IoC container they are useless. Anyway it's important to provide some sort of abstraction, because it allows to easily mock up objects and implement unit tests of a service layer. I'm not a fan of writing tests of every piece of code, but the most crucial parts of a system should be well tested before they are being uploaded to the repository. Such an architecture allows to do it easily and provides a programmer with a well maintainable code.

There are also drawbacks of such solution. The biggest one is the increase of a time needed to implement an application. However, in my opinion it doesn't really matter, because such architecture guarantees a high quality of an application. Of course every developer needs to implement classes from each layer in such way that the code is as consistent as possible. Once he had done it - the application becomes easily scalable and maintainable.

In my next post I will write some of the most common solutions that I'm applying in my projects. After that I will upload a sample project with a proper architecture, IoC container (Ninject for sure) and base classes for controllers and view pages. Stay tuned.

When I was writing this page I wanted it's content to be available even when user has javascript's turned off. That way website, can be easily indexed by search engines, and contain a very nice transition effects.

I was looking for as simple solution as possible. After a few minutes of searching on google I have found that ASP.NET MVC 3 allows to render a view without it's 'layout' (in previous versions called 'master') page in a very nice manner. All you have to do is to edit the _ViewStart.cshtml file and instead of a standard code:

    @{
        Layout = "~/Views/Shared/_Layout.cshtml";
    }

Put the following:

    @{
        string ajax = (string)Request.Params["ajax"];
        if (String.IsNullOrWhiteSpace(ajax))
        {
            Layout = "~/Views/Shared/_Layout.cshtml";
        }
        else
        {
            Layout = null;
        }
    }

Now apply some jQuery magic to menu buttons so that they load a content to the specified container and send within each request an "ajax" parameter, which can be any non empty string.

Voila! Works like a charm. On a stackoverflow there is a suggestion to use Request.IsAjaxRequest() to verify whether layout page should be loaded. Personally I'm not convinced to do this, because this method bases on a "X-Requested-With" http header which is set by many javascript frameworks, but there is never 100% chance that it will be always present. For example in some cases of ajax file upload there may be a problem, since Internet Explorer and Opera don't support file sending through XMLHttpRequest object. Because it's not a big problem for me to send at each ajax request additional parameter - I prefer more stable solution.

Ok, so this is my first post! First of all: why did I set up this blog?

There are two main reasons:

In my everyday work, when I find an interesting solution, there are big chances that I will use it in a future. For this purpos,e I will try to put here all code samples that i have found. It will save me a lot of time, since I won't have to browse my old project's source code.

Second reason - knowledge sharing. Many times I have found a help by reading other programming biased blogs. I hope this place will become a pay off to the programmers society.

For now - the blog is... Ok. In fact I need to implement it (it's plain html now). Since it will be a very simple blogging system I won't have much work with that. Unfortunately, right now I'm very busy, so I suppose that it's final version should be available somewhere around November/December. Probably on this date I will find two or three days to sit down and code it.

By the way - I can't miss an opportunity to test how Syntaxhighlighter will work here. Here comes the simple test:

    public class HelloWorld
    {
        public void Hello()
        {
            Console.WriteLine("Hello World!");
        }
    }