The top story in my favorite aggregator today is the announcement on Scott Guthrie’s blog of the ASP.NET 3.5 Extensions CTP Preview. Normally, announcements related to ASP.NET would not interest me except this time is an interesting item in the list of technologies being released

ADO.NET Data Services: In parallel with the ASP.NET Extensions release we will also be releasing the ADO.NET Entity Framework.  This provides a modeling framework that enables developers to define a conceptual model of a database schema that closely aligns to a real world view of the information.  We will also be shipping a new set of data services (codename "Astoria") that make it easy to expose REST based API endpoints from within your ASP.NET applications.

Wow. It looks like Astoria has quickly moved from being an experimental project to see what it would like to place RESTful interfaces on top of SQL Server database to being very close to shipping a production version.  I dug around for more posts about Astoria ADO.NET Data Services so I could find out what was in the CTP and came across two posts from Mike Flasko and Andy Conrad respectively.

In his post entitled ADO.NET Data Services ("Project Astoria") CTP is Released on the ADO.NET Data Services team blog Mike Flasko writes

The following features are in this CTP:

• Support to create ADO.NET Data Services backed by:
  • A relational database by leveraging the Entity Framework. 
  • Any data source (file, web service, custom store, application logic layer, etc)
• Serialization Formats:
• Industry standard AtomPub serialization
• JSON serialization
• Simple HTTP interface
  • Any platform with an HTTP stack can easily consume a data service
  • Designed to leverage HTTP semantics and infrastructure already deployed at large
• Client libraries:
  • .NET Framework
  • ASP.NET AJAX
  • Silverlight (coming soon)

This is sick. With Astoria I can expose my relational database or even a local just an XML file using a RESTful interface that utilizes the Atom Publishing Protocol or JSON. I am somewhat amused that one of the options is placing a RESTful interface over a SOAP Web Service. My, how times have changed…

It is pretty cool that Microsoft is the first major database vendor to bring the dream of the Atom store to fruition. I also like that one of the side effects of this is that there is now an AtomPub client library for .NET Framework.

Andy Conrad has a blog post entitled Linq to REST which gives an idea of what happens when you combine the Astoria client library with the Language Integrated Query (LINQ) features of C# 3.0

    [OpenObject("PropBag")]
    public class Product{
        private Dictionary<string, object> propBag = new Dictionary<string, object>();

        [Key]
        public int ProductID { get; set; }        
        public string ProductName { get; set; }        
        public int UnitsInStock { get; set; }
        public IDictionary<string, object> PropBag { get { return propBag; } }
    }

        static void Main(string[] args){
            WebDataContext context = new WebDataContext("http://localhost:18752/Northwind.svc");
            var query = from p in context.CreateQuery<Product>("Products")
                        where p.UnitsInStock > 100
                        select p;

            foreach (Product p in query){
                Console.WriteLine(p.ProductName + " , UnitsInStock= " + p.UnitsInStock);
            }

        } 

If you hover over the query variable, you will actually see the Astoria URI which the Linq query is translated into by the Astoria client library:

http://localhost:18752/Northwind.svc/Products?$filter=(UnitsInStock)%20gt%20(100)

So, there you go.  Linq to Astoria's RESTFUL API.  In other words, Linq to REST. 

Like I said earlier, this is sick. I need to holla at Andy and see if there is a dependency on the Atom feed containing Microsoft specific extensions or whether this Linq to REST capability can be utilized over any arbitrary Atom feed.

Now playing: Jay-Z - Success (feat. Nas)