How do I choose between WCF, REST, POX and RIA services for a new Silverlight application

Question

There a lot of different ways a Silverlight application can connect back to it’ server. Including

• WCF - Windows Communication Foundation

Answer 1

My two (euro) cents:

WCF seems best suited when the service can be viewed as the business layer of the application, that is, when your service has "intelligent" operations like "CalculateDiscountForClient".

ADO.NET Data Services (indeed, just a REST implementation) seems appropriate when your application is basically data-centric and the service is simply a front-end for the database. That is, all your service methods are of type GetCustomers, CreateInvoice, etc.

RIA services is a very new technology that I haven't experimented with yet, but it seems to be useful to create applications in which the Silverlight part and the service are very tightly coupled: you define your service classes and methods in the service project, and they are automatically replicated to the Silverlight project in design time. Also, you can define both WCF-style "action" methods and ADO.NET Data Services-style "data" methods. Looks promising.

Use POX if there is a chance that you change the client part from Silverlight to any other technology (for example HTML+AJAX) in the future, since it is the most interoperable option.

About differences for WPF, the only I can think of, is that for data access, whenever possible I would use direct ADO.NET data connections (properly embedded in a data access layer, LINQ to SQL or the like) instead of ADO.NET Data Services, since it is way more flexible. I must say anyway that I have never developed anything in WPF.