Andrew Tokeley

RIA Services – ADO.NET Data Services and WCF

Tokes — Sun, 01 Nov 2009 04:28:23 GMT

I’ve had a chance to look at RIA Services over the last few months and thought it would be good to clear up some of the confusion over where RIA Services stands in relation to other related technologies like ADO.NET Data Services and WCF.

In some respects RIA Services are similar to WCF Services. You write the service code, host it on a server, create some proxy classes on your client and away you go. In fact, if you look at how you implement the same service in each technology it’s almost identical.

In WCF,

[ServiceContract]

public class SpeechService : ISpeechService

{

    [OperationContract]

    public CreateWavStreamResponse CreateWavStream(CreateWavStreamRequest request)

    {

        ...

    }

}

In RIA Services,

[EnableClientAccess()]

public class SpeechDomainService : DomainService , ISpeechService

{

    [ServiceOperation]

    public CreateWavStreamResponse CreateWavStream(CreateWavStreamRequest request)

    {

        ...

    }

}

In both cases a proxy class is created when the service is referenced. In the case of RIA Services the proxy (DomainContext) is created automatically when you compile your Silverlight solution. For WCF the proxy is created when you explicitly reference the service via, for example, the Add Service menu option in Visual Studio.

In this example the main difference between the two technologies is in the way the messages are constructed and sent between the client and service. In the case of WCF you get to choose your binding (HTTP, HTTPS, TCP) and transport (usually SOAP but REST is possible if the length of this white paper doesn’t put you off!). The current version of RIA Services (July 2009 CTP) only supports HTTP, REST-style services that use JSON to package the contents of the messages. The current implementation follows a very similar pattern to that used by ADO.Net Data Services. In fact Tim Heuer states the next version will adopt ADO.Net Data Services completely.

And even further down the track it looks like they’ll be incorporating some of the power of WCF into the transport layer. For example, Brad Abrams mentions,

“We also expect to eventually provide full access to all the power and flexibility from the underlying WCF services such as highly optimized binary serialization. “

RIA Services aligns further with ADO.Net Data Services by automatically allowing you to generate CRUD style operations against data stores. Simply point to a data store and away you go. Doing this in RIA Services results in a (server-side) service that looks something like,

[EnableClientAccess()]

public class BlogDomainService : LinqToSqlDomainService<BlogDataDataContext>

{

    public IQueryable<Category> GetCategories() ...    

    public void InsertCategory(Category category) ...

    public void UpdateCategory(Category currentCategory) ...

    public void DeleteCategory(Category category) ...

    public IQueryable<Comment> GetComments() ...

    public void InsertComment(Comment comment) ...

    public void UpdateComment(Comment currentComment) ...

    public void DeleteComment(Comment comment) ...

    ...

}

The implementation of the service is based on LinqToSQL – this is likely be extended over time.

The operations of which, can be called from the client, via an auto-generated proxy, using REST-style web requests that look very much like ADO.Net Data Service requests. For example, a request for all Postings would be constructed as a GET request to a URI like,

http://[yoursite]/ClientBin/DataService.axd/[yourRIAServicename/GetPostings

RIA Services processes this request and returns an HTTP Response where the contents of the response are serialised using JSON.

Note: The above screen-shot is from Nikhilk’s IE browser extension, Web Development Helper that seemed to be one of the few HTTP traffic capture tools that allows you to view JSON output in a tree-view.

Of course, RIA Services is more than another way of simplifying distributed data transfer. It contains many other features that have nothing to do with either ADO.Net Services or WCF including,

Integration with ASP.NET’s security model – forget about the complexity of WCF security, this is how easy securing services should be!
Client-side Validation – all validations defined on your server-side entities (using familiar Data Annotations) will be automatically transferred to the client.
Silverlight Control Support - because of the way Data Annotations are used a number of Silverlight controls will honour the validation rules also. For example, the DataGrid and DataForm will both display validation error messages without you doing a thing.
Offline Support – all changes to your entities are batched within ChangeSets that can be saved to IsolatedStorage when not online.

So, there you have it. Be confused no more ;-)

Learn About RIA Services

Tokes — Fri, 23 Oct 2009 19:47:10 GMT

If you can make it to Wellington next Wednesday (6:00pm @ Xero) come along and hear all about RIA Services at the next Silverlight User Group (SLUG). I’ll be covering some of the stuff I presented this year at TechEd but also adding a few new things. I’m also keen to hear what people think about RIA Services compared to alternative approaches – is it something you’ll use? If not, why not? If so, what’s so great about it?

You can find out more here.

and register with Sky at, skysigal@xact-solutions.com

Intergen at Tech.Ed 2009 – More Movies

Tokes — Sat, 10 Oct 2009 00:39:11 GMT

Intergen were there in force this year and here’s the proof…

Windows Azure for High Availability [TTK155] (Chris Auld)

Windows Azure, the Microsoft Cloud Computing Platform with particular reference to high scalability and availability the platform offers and how this can benefit NZ businesses.

Sponsors Spotlight - Intergen [TTK136] (Tony Stewart)

Meet Tech.Ed NZ's sponsor for 2009 and find out their latest offerings.

Silverlight Adoption [TTK147] (Me)

For anyone who has worked with Silverlight, it opens up a whole new set of possibilities for building feature rich applications delivered across the internet. So why would you bother trying to build these types of applications using HTML/CSS/JavaScript - technologies that were never designed to be taken as far as they have? Andrew Tokeley has been pondering this for a while now and will be talking with Nigel to share some of his thoughts.

Panel Discussion - Designers & Developers How We Do It In the Real World. [WUX212] (Me in Panel)

Join Nigel Parker (Microsoft NZ Web Development Advisor) as he moderates a discussion with a panel of industry leaders about how Developers & Designers work together on real world projects. This panel is intended to be engaging, provocative and insightful. Come along with your questions and ideas and be prepared to contribute to the last session of Tech.Ed NZ.

Building Great Standards Based Websites with ASP.NET 4.0 and Silverlight 3 [WUX304] (Me with Damian Edwards)

In this session, Damian Edwards will share his experiences from building Australia's largest e-commerce site with ASP.NET Web Forms. They'll show you how to be a good web citizen by covering standards compliance (properly!), cross browser and accessibility considerations, non-JavaScript support, as well as coding techniques like the Model-View-Presenter pattern to improve maintainability and testing. Along the way, there'll be plenty of discussion of the differences between Web Forms and ASP.NET MVC in each area, as well as an early peek at some of the new features coming in ASP.NET 4.0 and VS 2010. Following this Andrew Tokeley will show you how it is possible to build highly accessible web applications by leveraging the accessibility features of Silverlight and discusses using Silverlight under the New Zealand e-Government Web Guidelines.

An Overview of the Azure Services Platform [ARC201] (Chris)

Cloud computing looks like the biggest change to hit our industry in many years. One important aspect of this change is the rise of platforms that let developers create applications for the cloud. This session takes a broad look at the Azure Services Platform, Microsoft's entry in this area. The topics discussed include Windows Azure, .NET services, Microsoft SQL Services, and Live Services. The goal is to make clear what these technologies can do, then offer some guidance on how to make good decisions for using them.

Community Spotlight - Mark Orange [TTK129] (OJ)

The New Zealand .NET Community meets regularly and showcases innovative NZ technology best practices. See the people behind the .NET community and connect with them at your local user group. Meet Mark Orange, the lead for the Wellington SharePoint User Group.

Business Productivity Online Suite (OJ)

High functionality, low complexity and cost: Microsoft made BPOS available in New Zealand in March 2009, so what is it and what's it good for? With its mix of Microsoft services hosted in the cloud it is the emergence of something that will become not only common place but critical to industry. Companies had the infrastructure to generate all their own electricity once, we are still in that era with computing power.

Silverlight Adoption – The Movie

Tokes — Fri, 09 Oct 2009 21:11:28 GMT

TechEd 2009 seems so long ago now that I had thought Microsoft had made an editorial decision to scrap my Tech Talk with Nigel on Silverlight adoption. I was sure I hadn’t said anything to offend but I was beginning to wonder. So it was with relief that I finally found it… check it out.

ButtercupReader is on CodePlex

Tokes — Mon, 28 Sep 2009 21:55:36 GMT

If you’ve been following the work we did on ButtercupReader (a Silverlight application for reading DAISY formatted digital books) then you might be interested to get your hands on the source code to see how it was done.

We’ve just published the code to CodePlex - http://buttercupreader.codeplex.com.

So, check it out and we’d love to hear your feedback and hopefully get some help to drive the project forward.

TechEd 2009 – Slides and Downloads

Tokes — Tue, 15 Sep 2009 04:13:53 GMT

Thanks to everyone who came along to my sessions. As promised, here are the code/slides downloads.

WUX304 - Building Great Standards Based Websites with ASP.NET 4.0 and Silverlight 3 (Silverlight sections only)

WUX308 - Building Awesome Business Centric Applications with .NET RIA Services

UISpy – Download it Here!

Tokes — Tue, 15 Sep 2009 03:51:46 GMT

If you’ve ever tried to get hold of the UISpy you’ll know it requires a bit of searching in previous Windows SDK downloads – all this is a pain when all you need is the exe itself. So, to ease your pain grab it here.

UISpy.zip

Cheers

Silverlight Install Experience – Keep it Simple

Tokes — Fri, 14 Aug 2009 03:28:34 GMT

Don’t get me wrong – I love Silverlight. But this sort of user experience is shocking. Here’s a screenshot of the page a user - who may never have heard about Silverlight before and is probably a computer novice – has to get their head around. This does nothing to improve Silverlight adoption.

Compare this with the page to install page for Flash.

Enough said.

What Developer Podcasts Do You Listen To?

Tokes — Wed, 05 Aug 2009 10:51:07 GMT

I love listening to developer podcasts while running or on the commute to and from work. These are the ones I regularly listen to,

Are there any other ones you’d recommend?

UPDATED…

Here are some more that people have suggested,

http://polymorphicpodcast.com/
http://aspnetpodcast.com/CS11/ (has gone a bit quiet as Simone pointed out)
http://blog.stackoverflow.com/category/podcasts/
http://itc.conversationsnetwork.org/ - not only about development but includes StackOverflow and other technical podcasts

Calling All Solution Architects

Tokes — Wed, 05 Aug 2009 10:40:32 GMT

A new group is forming in Wellington focused on the pretty broad and often ill-defined topic of Solution Architecture. Here’s the poster to put on the office wall and more details from the organiser Adrian Kearns. I’ll certainly be heading along – see you there.

The aim of this group is to provide practical information and support for anyone who "does" solution or software architecture.

It doesn't matter if you're a full-time architect or not. Maybe you're just "aspiring"? Maybe your focus is more specific (say as a software, data, security or technical architect)? Either way, we're here to help.

The WASF is technology and vendor agnostic - in fact our focus isn't strictly just technology; we'll also cover the so called "softer" skills, which are arguably harder - such as politics and people skills.

YOU can present! We'll be featuring local (not sometimes not-so-local) people to share their knowledge and you can share too. If you have something you want to share or some work you'd like peer-reviewed you present to the forum in a 5-10 minute slot and get valuable feedback from the community.

So spread the word! Pass this on to anyone a friendly architect near you.

In order to make this worthwhile for the community we need community input: come to the first meeting so we can hear your views, or contact us.

Got a question for the speakers - send it to us.

Who are we?

The WASF is led by Amir Shevat (Senior architect and consultant with Datacom) and Adrian Kearns (Solutions Architect with the NZTA). As Amir is currently on holiday, please contact Adrian (adrian.kearns@nzta.govt.nz) with enquiries' or for more information.

First Meeting: 2nd September 2009, networking from 12 noon, 'formal' sessions from 12:30 pm - 1:30 pm.

Venue: Microsoft NZ Boardroom, Level 12 Vodefone House, 157 Lambton Quay.

Food: BYO Lunch.

Admission: Yes! Free, no charge.

Agenda:

What the WASF is all about and how you can contribute.

Cloud Sourced: Representatives from Microsoft and Cloudbreak will be on hand to answer you Cloud questions. Hear how Microsoft Azure and the Google Apps Engine compare.

Agile and Architecture: Explore the intersection of architecture and agile with agile coach Sandy Mamoli.