What MS technology to use for HTTP service returning XML?

Question

I need to create a service that:

1. accepts HTTP requests (with query string or HTTP POST parameters)
2. does some processing on the requests (checking if the request is valid, authentication etc.)
3. reads data from a custom store (another HTTP call in our case)
4. returns the result as custom XML (defined with XSD)

I'm trying to think of various MS technologies that could help me and how good they would be for this scenario (pretty standard one I guess).

The tasks above are relatively separate, this is what comes to mind:

HTTP front-end:

• ASP.NET Web Forms
• ASP.NET MVC (seems more appropriate here as I won't need server controls, view state etc.)
• WCF? Don't know much about it or how well it would suit my task.

Custom logic on the server:

• this will probably be a generic C# code in all cases (sometimes "plugged into" or called from MVC controllers or some equivalent place in other technologies)

Reading data from internal data stores:

As said, this is another HTTP server in our case. Options that come to mind:

• Just read the data using something like WebClient
• (Just theoretically) implement a LINQ provider
• (Just even more theoretically) implement an EF provider

Output the data as custom XML:

• Linq2XML
• Serialization? Is it flexible enough?
• Does WCF provide some tools for this?
• Some "OXM" - Object/XML mapper if there is something like that for .NET

I may be wrong in many of my assumptions, this is just a quick list that comes to mind after a quick research.

Some general notes / questions:

• Testing is important
• Solution with a clear domain model would be much preferred over the one without
• Can Entity Framework actually help somewhere in my scenario? If so, where and how?
• Would WCF be an appropriate technology for this? I don't know much about it.

Answer 1

ASP.NET MVC can return an XML result, in any flavor you like. ASP.NET MVC is specifically designed to be testable. Use whatever suits your temperament to generate the XML. URLs are mapped directly to a C# controller method that returns the XML to the user. The URL routing capability in ASP.NET MVC provides great flexibility in defining your URL structure and mapping that structure to controller methods. You can use Entity Framework to create your domain model and read from the data store.

WCF should be capable of this as well, if you just want to build the service without a UI. Here is a primer: http://msdn.microsoft.com/en-us/library/dd203052.aspx

The NerdDinner tutorial is the definitive primer for ASP.NET MVC.

More info on the Entity Framework here: http://msdn.microsoft.com/en-us/library/aa697427(VS.80).aspx

Answer 2

WCF with the REST style webHttpBinding does exactly that - check out the WCF REST Developer Center for a ton of intro articles, blog posts, videos, white papers and so forth.

Building on top of WCF REST, there's also WCF Data Services - formerly known as "Astoria" or ADO.NET Data Services - which offers a uniform access to your data models. It's been formalized into the Open Data Protocol (OData) and is being touted as the next big thing in data access from Microsoft - check it out, well worth a close look!