In case you haven't noticed yet, the bits for .NET 3.5 SP1 Beta 1 and Visual Studio 2008  SP1 Beta 1 are now available...take a minute and go grab them, and then you can finish reading this post while they install :)

What's new?
Looking at the platform holistically, the big-ticket features in SP1 are the ADO.NET Entity Framework (finally ;) ) and the ADO.NET Data Services (Astoria). I'm sure lots of folks will be talking in-depth about those things, so I'll focus on some of the smaller (but no less interesting!) features that my team is delivering as part of this release.

From the WCF/WF perspective, here's what you can look for in SP1. There's a lot here and each one of these probably merits an individual post but here are the bullet points:

Core Framework

• Expanded UriTemplate syntax including support for compound template segments (like /{filename}.{ext} and /customers({id})), default values (like /customers/{id=0}), and optional trailing slashes.
• Syndication OM for the Atom Publishing Protocol. We added strongly-typed OM for all of the constructs defined in the Atom Publishing Protocol specification (like ServiceDocument and Workspaces) and put them in the System.ServiceModel.Syndication namespace.
• Attribute-free Data Contract serialization. The DataContract serializer now supports a model that doesn't require you to put [DataContract]/[DataMember] on every serializable member.
• Interoperable Object References. The DataContract Serializer now supports an interoperable object reference scheme that allows it to serialize object graphs (not just trees). Thanks to this, Entity Framework types are also serializable via the DataContract serializer.
• Improved logging/tracing in Partial Trust. We added more of our diagnostic/tracing path to the partial trust sandbox to improve the debuggability of hosted applications running in partial trust.
• Scalability Improvements on IIS7: It's now possible to plug WCF into IIS7 asynchronously instead of synchronously, which can improve overall throughput and thread utilization on IIS7 for a class of high-latency scenarios.

Tools

• Enhanced Service Test Client: The Test Client can now test services that use MessageContract/XmlSerializer types as well as Nullable<T>.
• Hosting Wizard: There's now some tooling support for deploying Service Library projects to a host environment
• Workflow Designer Performance Improvements: Auto-Save is faster now. A LOT faster.
• Silverlight Templates: Visual Studio templates for WCF services in Silverlight, nuff said.

We've managed to put a lot into this little release...take a look at the new bits and tell us what you think.

You should seriously check out Brian's F# blog. It's way good.

Brian is a WCF alum; he owned a hefty chunk of the code in System.ServiceModel.Dispatcher and the 3.5 Web Programming Model work.

It's funny...I used to mistype his name in emails a "Brain McNamara" at least once a week, which actually was a pretty accurate statement.

Anyway, he's over in 41 working on the F# compiler now and blogging up a storm. I'm spending more time getting to know the F# language, and I'm liking what I'm seeing.

Nicholas has a good post on the binding validation WCF does in partial trust.

As he points out, a ServiceHost running in anything less than a fully trusted AppDomin will so some baked-in validation on the bindings being used. Specifically, we have a list of binding elements that are explicitly prohibited in partial trust, and if we catch you trying to use one of these binding elements we'll prevent your service from activating.

This behavior has absolutely nothing (zip, zero, nada) to do with security. For that, we rely on the Code Access Security features implemented by the CLR, like any other framework component.

So why do we do this validation? One reason -- usability. Exceptions at deterministic times (say, Open()) are vastly better than exceptions at random times (say, when you receive a message that triggers a code path that does a demand for a permission you don't have). Having binding validation in place doesn't make the system more secure, but does avoid exposure to a large class of issues that can be pretty hard to reproduce and diagnose.

Sadly, duty called and I didn't get to make it to Mix '08 this year. To make up for it, I think I'll take a couple days this week to watch some recorded sessions via teh intarweb and then drive to the Indian casino in Everett.

Here's what's in my queue:

http://sessions.visitmix.com/?selectedSearch=T26 -- Justin Smith on the NetFx 3.5 WCF Web Programming Model
http://sessions.visitmix.com/?selectedSearch=T19 – Pablo on talking to Windows Live Services via AtomPub
http://sessions.visitmix.com/?selectedSearch=BT02 – Mike Flasko’s Astoria overview
http://sessions.visitmix.com/?selectedSearch=T22 – Scott Hanselman’s MVC overview
http://sessions.visitmix.com/?selectedSearch=T28 – John Lam on the DLR
http://sessions.visitmix.com/?selectedSearch=T07 – another Astoria talk, this one from Pablo
http://sessions.visitmix.com/?selectedSearch=T13 – our very own EugeneOs on web services and Silverlight

But of course the big one for me is Creating a RESTful API with Windows Communication Foundation, presented by Haider Sabri and some friends from the MySpace developer API team. These guys have been building the public-facing MySpace REST API as a set of WCF services and were kind enough to do a talk at Mix about their experience. They even built a cool demo app -- http://www.restchess.com using WCF and shared the source for everyone to play with. There's a sweet (and highly reusable) OAuth channel in there along with lots of other goodies...thanks guys!

Lots of folks have asked me how to add various XMLism like XML Namespace prefixes to the serialized output of a SyndicationFeed. This is actually easy to do once you know the trick but it's admittedly not the most obvious thing in the world.

The thing to remember is that the System.Xml stack treats prefix declarations as special kinds of attributes. If you want to emit an XML namespace declaration of xmlns:contoso=http://schemas.contoso.comyou need to emit attribute whose name is the prefix you're declaring (e.g. "contoso"), whose value is the namespace URI that corresponds to the prefix (e.g. 'http://schemas.contoso.com'). This attribute needs to be in the special XML namespace declaration namespace (!) of http://www.w3.org/2000/xmlns/

Since SyndicationFeed supports additional XML attributes through the AttributeExtensions property, you can do this on SyndicationFeed as follows (using the C# 3.0 collection initializer syntax, natch):

SyndicationFeed feed = new SyndicationFeed()
{

   AttributeExtensions =

  {
     { new XmlQualifiedName("contoso", " http://www.w3.org/2000/xmlns/") , "http://schemas.constoso.com " }
  }
};

If you like syntactic sugar, here are a few extension methods that add a helper function to all of the OM constructs that support attribute extensibility:

using System;
using System.Xml;
using System.ServiceModel.Syndication;

namespace Samples
{
    public static class SyndicationExtensions
    {
        public static void DeclareNamespace(this SyndicationFeed feed, string prefix, string nsUri)
        {
            feed.AttributeExtensions.Add(new XmlQualifiedName( prefix, " http://www.w3.org/2000/xmlns/" ), nsUri);
        }

        public static void DeclareNamespace(this SyndicationItem item, string prefix, string nsUri)
        {
            item.AttributeExtensions.Add(new XmlQualifiedName(prefix, " http://www.w3.org/2000/xmlns/") , nsUri);
        }

        public static void DeclareNamespace(this SyndicationCategory category, string prefix, string nsUri)
        {
            category.AttributeExtensions.Add(new XmlQualifiedName(prefix, " http://www.w3.org/2000/xmlns/") , nsUri);
        }

        public static void DeclareNamespace(this SyndicationLink link, string prefix, string nsUri)
        {
            link.AttributeExtensions.Add(new XmlQualifiedName(prefix, " http://www.w3.org/2000/xmlns/") , nsUri);
        }

        public static void DeclareNamespace(this SyndicationPerson person, string prefix, string nsUri)
        {
            person.AttributeExtensions.Add(new XmlQualifiedName(prefix, " http://www.w3.org/2000/xmlns/") , nsUri);
        }
    }
}

On a side note, I'm becoming a huge fan of extension methods. They are not perfect, but I expect that their existence will have a pretty substantial impact on the way the internals of the framework get factored in future versions...

One of the things that the DataContractSerializer does is create a mapping between CLR type names and XML qnames.

Lots of people know that you can control this mapping on a per-type basis via the [DataContract] attribute, e.g.

namespace Contoso.Serialization
{
  [DataContract( Namespace="http://schemas.contoso.com/2008" )]
  public class Person
  {

     [DataMember]
     public string Name { get; set; }
  }
}

Having to explicitly specify this on every type gets a little laborious, especially if you just want to say "put all types in this CLR namespace into this XML namespace".

Few people know that there's a simple way to do this via the assembly-level ContractNamespaceAttribute:

[assembly: ContractNamespace( "http://schemas.contoso.com/2008", ClrNamespace="Contoso.Serialization" )]

If you have that, then you can just say [DataContract] (sans Namespace="...") and it's just as if you had said [DataContract( Namespace="http://schemas.contoso.com/2008" )] for all [DataContract] types in the Contoso.Serialization namespace.

That comes in handy from time to time and can save some keystrokes.

This has been around since .NET 3.0, but I didn't know about it until recently. Figured not many other people did either :)

I thought this post from Ganesh Prasad was both cheeky and refreshing:

Though I like REST and consider it a very elegant model for SOA, it's a little tiresome to hear day in and day out that it's so much more elegant than the SOAP-based Web Services model. In fact, I'm getting so tired of this shrill posturing that I'm going to stick it to the RESTafarians right now, in their own style. Watch.

Paying the RESTafarians Back in Their Own Coin

I think I would get along well with Ganesh.