Nicholas Allen's Indigo Blog

Reaching a More Permanent Conclusion

2010-06-30T12:00:00Z

Taking some mandatory time off for system maintenance and upgrading grew into deciding that the time was right to make the arrangement more permanent. That was probably apparent a few weeks ago but officially now the 1,111th post here is also the last one.

I’m done but there’s still plenty more to say about WCF. For continued news and updates at least try the Endpoint blog by Ron Jacobs. Regularly delivered technical content is a little harder to find but I hope that someone on the team is able to take on that opportunity in the future. In the meantime you do have more than a thousand articles to read if you haven’t already.

Extended Down Time

2010-05-13T12:00:00Z

MSDN will be migrating to a new blog platform during all of next week. During that time comments will be disabled, posts will be in the process of migration, and new theme and profile systems will be switched in. I’m planning to hold off trying to post on the normal schedule to avoid having to deal with the pain of migration. That means no posts for at least the next week until everything is back to normal. The entire archive should remain available during this time.

Identity Framework SDK and Training Kit for Visual Studio 2010

2010-05-12T12:00:00Z

A new version of the Windows Identity Framework SDK and developer training kit is available targeting Visual Studio 2010 and .Net 4. The Windows Identity Framework SDK includes samples and Visual Studio templates while the training kit includes hands-on labs and training resources.

The SDK and training kit each have a download option for .Net 3.5 and a download option for .Net 4. It looks like installing both versions of either the SDK or training kit does not work particularly well. The .Net 3.5 option is for use with Visual Studio 2008. The .Net 4 option is for use with Visual Studio 2010. Pick the option matching the framework and Visual Studio version you’ll be using. One exception is that the .Net 4 training kit includes Windows Azure resources targeted at .Net 3.5.

Debugging a Missing HostedTransportConfiguration Type

2010-05-11T12:00:00Z

When browsing to a service hosted in IIS I get an error that the protocol does not have an implementation of HostedTransportConfiguration type registered. What can cause this?

Two things to look at are the IIS site bindings and the installed activation services. All of these examples use net.tcp with default settings but you can substitute in other protocols and options similarly following the same checklist.

First, a configuration for the protocol scheme needs to be associated with the web site. This is normally done when the web site is first set up, but you can add additional site bindings from the command line using the appcmd utility.

appcmd set site "Default Web Site" -+bindings.[protocol='net.tcp',bindingInformation='808:*']

Second, the site binding for the web site needs to be enabled on the particular application that is to be activated. Again, this is usually done when the web site is first set up but can be changed using the appcmd utility.

appcmd set app "Default Web Site/myapp" /enabledProtocols:net.tcp

Finally, the service that hosts the protocol handler needs to be installed and running. You can check the status of the activation service using the sc utility.

sc query nettcpactivator

If the service is not present or is stopped, then that likely means that the Windows component (for client versions of Windows) or the server role and features (for server versions of Windows) are not enabled. The pkgmgr utility can be used to update the component setup.

pkgmgr /iu: WCF-NonHTTP-Activation

WCF Data Services V1 Client Library and Update

2010-05-10T12:00:00Z

The WCF Data Services team has released the source code for their OData client libraries on .Net 3.5 SP1 and Silverlight 3. This may be of benefit to anyone trying to write their own library for the OData protocol. OData is a protocol for querying and updating data stored using a particular class of data models. The source code is released under the Apache 2 license.

Also recently they’ve put out an update to ADO.NET Data Services for Windows 7 and Windows Server 2008 R2. Data Services are REST-based web services that expose a data model that can be consumed by web clients. Data Services use URIs to address data from a storage system and supports a variety of formats for representing that data, such as JSON or ATOM. This update addresses the issues listed in KB article 982307.

Claims Visualization

2010-05-07T12:00:00Z

Dominick Baier has a visualization for claims in the Visual Studio debugger. I’m not sure what other details to provide. It takes an identity and description for a claim and describes the issuer, metadata, and properties that make up the claim.

Service Activation without Files

2010-05-06T12:00:00Z

WCF services in IIS use a .svc file to bootstrap the process of activating a service. It’s possible but not recommended to put the entire service source code and definition in a .svc file to be dynamically compiled and run. Instead, the information that’s typically conveyed is:

The identity of the service being instantiated
The base address at which the service exists within the address space of the overall web site
The service host factory type that will be used to construct the service host

Based on the provided information, the service host factory is created, the service definition is loaded, and the service starts listening on the base address.

In .Net 4 it’s possible to define services through application or machine configuration as an alternative to creating a .svc file. The configuration includes the same information the .svc file would.

Service activation configuration is a new configuration element within the ServiceHostingEnvironment configuration section. The service activation configuration is a collection of service definitions that specify for each service:

The identity of the service being instantiated
The relative address at which you would have put the service file before
The service host factory type that will be used to construct the service host

The relative address functions exactly as if a file exists at the specified location. Based on the path of the relative address, requests will be passed to the service. Based on the extension of the relative address, a build provider will be invoked to construct the service. The only difference from before is that you don’t have to actually create or deploy the separate service files. Service files are virtualized from the information provided in the configuration.

Routing and Impersonation

2010-05-05T12:00:00Z

Can the routing service introduced with .Net 4 be used with impersonation?

Yes, the routing service can be used with impersonation for both sending and receiving messages. All of the usual Windows constraints of impersonation apply. If you would have needed to set up service or account permissions to use impersonation when writing your own service, then you’ll have to do those same steps to use impersonation with the routing service. The WCF configuration for impersonation is simplified though.

Impersonation with the routing service requires either the use of ASP.NET impersonation while in ASP.NET compatibility mode or the use of Windows credentials that have been configured to allow impersonation.

The only step to use ASP.NET impersonation with the routing service is to enable ASP.NET compatibility mode on the service hosting environment. The routing service has already been marked as allowing ASP.NET compatibility mode and impersonation will automatically be enabled. Impersonation is the only supported use of ASP.NET integration with the routing service.

To use Windows credential impersonation with the routing service you need to configure both the credentials and the service. The client credentials object that you use has an allowed impersonation level that must be set to permit impersonation. Finally, on the service you need to configure the ServiceAuthorization behavior to set ImpersonateCallerForAllOperations to true. The routing service uses this flag to decide whether to create the clients for forwarding messages with impersonation enabled.

Multiple Site Bindings

2010-05-04T12:00:00Z

A WCF application in IIS is a service page that is hosted under a site. You can assign different bindings to the site that describe the protocols through which the site can communicate. It’s possible to assign multiple protocols to a single site by specifying bindings that have different protocol schemes. It’s also possible to assign multiple addresses for a single protocol to a single site by specifying bindings that have the same protocol scheme.

WCF has supported services hosted in IIS that have multiple protocols but not services that have multiple addresses for a single protocol. A service with multiple base addresses for a single protocol scheme would fail to start running when activated. You could partially work around this limitation by supplying base address prefix filters. A prefix filter allows you to pick one base address to use with your service for each protocol scheme.

<serviceHostingEnvironment>
<baseAddressPrefixFilters>
<add prefix=”http://www.example.com:80”/>
</baseAddressPrefixFilters>
</serviceHostingEnvironment>

After filtering, other pages in the site could use any of the addresses while still allowing the WCF service to run. However, the WCF service would only be listening on the portion of addresses that start with the path defined by the filter.

In 4.0 you can enable support for multiple bindings with IIS without having to pick a single base address.

<serviceHostingEnvironment multipleSiteBindingsEnabled=”true” />

This feature for using multiple bindings with IIS is limited to HTTP protocol schemes though.

May and June ReMIX 2010 Events

2010-05-03T12:00:00Z

ReMIX is an annual twist on the MIX conference that takes a small portion of the content presented at MIX and combines it with new content and local speakers for a variety of sites around the world. There are generally ReMIX events announced throughout the year starting shortly after the MIX conference is held in Las Vegas.

Here are a few that have been announced so far:

Atlanta, Georgia is hosting a ReMIX conference May 8th for the southeastern United States

Moscow is hosting ReMIX May 21st along with a DevConf WebCamp earlier in the week

Melbourne is hosting ReMIX during June 1st and 2nd

And of course you can always watch the online videos recorded from the original MIX conference.