Best way to implement a Generic Web Service API

Question

What is the best way to implement a open/cross platform web service API to an existing .NET App? Not being a strictly .NET friendly API. It already has ASP.NET exposed web services, but need to be built into an generic API allowing inserts, updates and deletes and returning results based on user criteria in standard SOAP, JSON or other common formats, similar to Google's Data API's.

Are there any frameworks designed for this or is it a build it from scratch project implementing each format/protocol manually?

Thanks.

Answer 1

Take a look at RIA services.

http://code.msdn.microsoft.com/RiaServices

Answer 2

Agatha Request Response service layer.

Answer 3

Leverage WCF Data Services (formerly ADO.Net Data services, formerly Astoria). If you need your own data service provider (instead of Linq to Entities for example), see Alex James' blog