A Cup of Silverlight, RIA & Interoperability : Intro

A cup of Silverlight, a drop of Architecture

Steve SFARTZ — Mon, 28 Jul 2008 13:04:00 GMT

We discussed before what Silverlight is about from a technical standpoint. Moving from theory to implementation, let's discuss today the architectural challenges when building a Silverlight App. The following considerations apply to Siliverlight 2 beta 2 (current version of Silverlight as of July 2008) :

A SilverLight app runs locally in the browser which renders a Web page composed of HTML code and a XAP archive. This archive contains presentation code (XAML), logic code (JavaScript, .Net or Dynamic) and Resources (Images… that may be accessed for Silverlight logic code).
The Silverlight app may interact with Services in two ways and through 5 different API’s
- HTTP stack
  - HTTP GET, POST / REST style : WebClient, HttpWebRequest
  - SOAP over HTTP : WCF client
- IP Socket
  - TCP : System.Net TCP Listener
  - Socket : System.Net Sockets
  - Duplex Channel: As a bonus, Silverlight 2 beta 2 brings among its set of news features, a duplex channel communication through its WCF support.

As we focus on Silverlight interop in this blog, we will detail the HTTP aspects only. Here is some global consideration from what we've learned so far :

To fully understand the above, may we bring some complementary vocabulary and explanations :

SOO - Site Of Origin designates the Web Site from which the XAP is downloaded, ie, your HTTP Web Server
The Business Logic is composed of the Web Services exposed to your SL client.

The Web Services may be running on the Site Of Origin or not. Depending on this topology, your security settings need to be adapted by adding a cross domain access policy at the root of the Web Services host endpoint. This secures the invocation of services from a Silverlight client whose Site of Origin does not host the requested services endpoint. For more information about cross domain, read scorbs post "Silverlight HTTP Networking Stack - Part 2 (Cross Domain Communication Overview)"

As the Web brings two services styles (SOAP/RPC & XML/REST), Silverlight supports both. To decide which one to use for your Silverlight data interactions, read "What are those SOAP/RPC and XML/REST styles ? ".

From those considerations, we propose to decline the Silverlight Architecte described above into Real World Enterprise Scenarios focusing on D2D, B2E, B2B or B2C scenarios: Silverlight scenarios for Rich Internet Applications,

To finish with, let's discuss interoperability. We named our Web & App Server layer as Interaction & Transactional Services to refer to Microsoft SOA Reference Architecture Model where 2 nature of SOA are introduced : SOA to interact and SOA to transact, the two being connected through interop channels. This is where our Silverlight plus ... Java, .Net, PHP, Ruby... comes into play.

Silverlight from a technical stand point

Steve SFARTZ — Thu, 24 Jul 2008 17:07:00 GMT

We have good news : everything you learnt about the Web applies to Silverlight development since Silverlight is an ActiveX which integrates with the HTML Document Object Model (DOM) and JavaScript both ways (ie, a Silverlight component can be exposed to JavaScript, and some Silverlight Business Logic can call Javascript).

A Silverlight application comes as a XAP archive (ZIP format) delivered as a resource on a HTTP Server which is referenced as the Web Site of Origin.

Developing a Silverlight application involves several skills :

XAML for Presentation,
a programming language for the UI Interaction & Business Logic (JavaScript, .Net and Dynamic languages)
Web Services knowledge to expose your data to the Silverlight client through the HTTP protocol (the style is opened SOAP/RPC or XML/REST)

XAML is an open specification (par of Microsoft Open Specification Promises - OSP) that enables declarative programming. A Silverlight XAML code create a hierarchy of components connected through by properties and events bindings.

<UserControl>

   <StackPanel Background="Turquoise">

          <TextBlock Text="Hello World"/>

          <Button Content="Click me/"/>

    </StackPanel>

</UserControl>

When it comes to programming, Silverlight V1 is restricted to JavaScript, whereas Silverlight V2 come with its .Net runtime (a lightweight CLR) and a Dynamic Language Runtime(DLR). Therefore, you get multiple development language options : JavaScript, C#, VB, Ruby and Python so far.

Silverlight conforms to Web Services standards (HTTP protocol, SOAP and XML formats). Yet, it brings its own restrictions and complements. These points will be largely discussed on this blog.

That said, we are ready to start the journey ... in our next post A cup of Silverlight, a drop of Architecture

Ressources

Silverlight Poster, Silverlight Deep Zoom Poster

Silverlight Architecture Overview on MSDN

A few things you may already know about Silverlight

Steve SFARTZ — Thu, 24 Jul 2008 16:49:00 GMT

Silverlight is a client technology which takes the Web to the next stage in terms of user experience.

Silverlight may be used to deliver Rich Media Experiences or Rich Internet Applications on the Web. V1 of Silverlight focused on Media, V2 focuses on RIA.

All you need to run Silverlight applications is a Web Browser should it be Internet Explorer, Firefox or Safari, on Windows or Mac. If you are a Linux desktop user, you should turn to Novell who delivers the Moonlight runtime, The technology & architecture issues detailled here also apply for Moonlight.

Silverlight 1 is RTM, while Silverlight 2 is in beta 2 as of July 2008 and will be RTM'd before the end of 2008.

A good way to discover Silverlight is to see it by yourself : Silverlight Gallery and a few RIA samples WoodGrove Financials, Faceout.

About a Cup of Silverlight

Steve SFARTZ — Wed, 23 Jul 2008 11:58:00 GMT

Silverlight is a terrific platform to build Rich Internet Applications. Yet, there is little practice on the Web to integrate the technology with others platforms.

The authors have good knowledge of the .Net and Java world to help you get the best of each.

You're a Java buddy : let us take you on the path to Rich Silverlight clients by leveraging on your Java skills and the tools you used to work with (Tomcat, Apache, Java frameworks)

You're a Silverlight guy : you may be interested in exploring the different ways to integrate Java Data & Business Logic into your apps

You're neither the one nor the other : the architecture & technical advices listed here apply to all environments. Hopefully, you 'll find samples for your preferred environment.

Ronny Kwon & Steve Sfartz