Ed's Blog

WCF Instancing mode default is InstanceContextMode.PerSession

edpinto — Mon, 16 Oct 2006 23:24:00 GMT

Keith Brown has been experimenting with InstanceContextMode. This is the property on System.ServiceModel.ServiceBehaviorAttribute that determines how WCF handles instancing. Keith correctly notes that the current documentation is wrong about the default value for this property. The default value is not PerCall, but rather PerSession. We changed this in the June CTP. Here's the reasoning:

"With PerCall, users who required a session in their ServiceContract would get a session that lasted the duration of a single call unless they changed the InstanceContextMode to PerSession.

With the new default of PerSession, users who require a session will get instance lifetime tied to session channel lifetime, as they expect. Users who don't require a session in their contract will still get instance lifetime that looks like PerCall. The benefit of this change is that users get the instance lifetime they expect once they set session requirements on the contract, without having to tweak the InstanceContextMode."

The docs have been updated on wcf.netfx3.com under the resources tab.

If you are building your service to be stateless, it shouldn't matter if the same instance is reused for the lifetime of a channel. Explicitly setting InstanceContextMode to PerCall simply means we will create a new InstanceContext for each call instead of reusing the instance associated with the session.

Vista Beta 2 to Jun CTP Breaking Changes

edpinto — Sat, 08 Jul 2006 00:16:00 GMT

The breaking changes for the June CTP have now been posted. Raw API changes are here. This is pretty significant because you won't see very many changes after these ones.

Here are the changes you are most likely to encounter when porting your apps

Base addresses are now supported in config for self-hosted services.

Before

//Code to create ServiceHost
Uri uri = new Uri(ConfigurationManager.AppSettings["baseAddress"]);
ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService), uri);

After

//Code to create ServiceHost
ServiceHost serviceHost = new ServiceHost(typeof(CalculatorService));

Configuration of behaviors has changed:

Behaviors are now scoped by service or by endpoint under system.serviceModel/behaviors/serviceBehaviors and system.serviceModel/behaviors/endpointBehaviors respectively. Further, the system.serviceModel/behaviors/behavior/@returnUnknownExceptionsAsFaults has been replaced with system.serviceModel/behaviors/serviceBehaviors/serviceDebug/@includeExceptionDetailInFaults. This attribute controls whether exception detail is included in a fault that occurs when a service encounters an unhandled exception.

Before

After

Metadata is now off by default so for a service to expose metadata, the ServiceMetadataBehavior must be configured on the service. When this behavior is present, you can publish metadata by configuring an endpoint to expose the IMetadataExchange contract. The following configuration exposes a mex endpoint at http://localhost/servicemodelsamples/service.svc/mex and also enables wsdl requests over HTTP GET at http://localhost/servicemodelsamples/service.svc?wsdl.

<behaviors>
      <serviceBehaviors>
        <behavior name="CalculatorServiceBehavior">
          <serviceMetadata httpGetEnabled="True"/>
          <serviceDebug includeExceptionDetailInFaults="False" />
        </behavior>
      </serviceBehaviors>
    </behaviors>
</system.serviceModel>
</configuration>

For client code updates, you should rerun svcutil.
Feel free to contact me, or ask questions on the WCF forum.

Feb CTP to Vista Beta 2 Breaking Changes

edpinto — Wed, 24 May 2006 19:37:00 GMT

Vista Beta 2 is here! There are relatively few changes from the Feb CTP because Vista Beta 2 was locked down shortly after the Feb CTP. You can find the breaking changes list here and the detailed api change report here.

Feb CTP Cert Tools

edpinto — Fri, 03 Mar 2006 21:30:00 GMT

The MakeCert.exe and CertMgr.exe tools that shipped with the February CTP SDK don't run on Windows XP SP2 and Windows Server 2003. If you happen to have Visual Studio 2005 installed with the .NET Framework SDK option, you can copy these tools from %ProgramFiles%\Microsoft Visual Studio 8\SDK\v2.0\Bin to the Windows SDK bin directory at %ProgramFiles%\Microsoft SDKs\Windows\v1.0\Bin. Alternatively, you can use the same tools from a previous SDK.

Breaking changes for the Feb CTP

edpinto — Wed, 22 Feb 2006 20:13:00 GMT

The Feb CTP is now available! A number of changes have been made that break existing code. The details have been posted here on our community site. Raw API change reports are available here for reference.

Here are some of the most popular things that you'll run into when you port your apps.

Service configuration has changed:

system.serviceModel/services/service/@type has changed to system.serviceModel/services/service/@name.

Before

After

Also note that names in config are now strictly treated as configuration strings and not necessarily as types. When using the WCF programming model the configuration names should be the full type names. Assembly qualified type names are no longer supported.

The format for the .svc files has changed:

Before

<%@Service language=c# Debug="true" class="Microsoft.ServiceModel.Samples.CalculatorService" %>

After

<%@ServiceHost language=c# Debug="true" Service="Microsoft.ServiceModel.Samples.CalculatorService" %>

Your best bet to update client code is to rerun svcutil.

Looking forward, we have most of the changes we know of to date completed, but we will continue to listen to customer feedback, and react to interop and security testing which could result in additional changes to the OM.

Feel free to contact me, or ask questions on the WCF forum.

WCF Beta 1 to Nov CTP Breaking Changes

edpinto — Thu, 15 Dec 2005 01:48:00 GMT

My name is Ed Pinto. I work on the team delivering the Windows Communication Foundation (WCF). Part of my responsibility is to focus on the usability of WCF. In an effort to make the transition to the Nov/05 CTP a little easier we've put together a list of breaking changes that describes changes you are most likely to run into when porting your app. Feel free to contact me, or ask questions on the WCF forum.

Major changes

Beta1	Nov/05 CTP
Config
Binding Names changed: Dropped ‘Profile’ and made transport naming consistent
wsProfileBinding	wsHttpBinding
wsProfileDualBinding	wsDualHttpBinding
netProfileTcpBinding	netTcpBinding
netProfileDualTcpBinding	netTcpBinding
netProfileNamedPipeBinding	netNamedPipeBinding
netProfileMsmqBinding	netMsmqBinding
msmqIntegrationBinding	msmqIntegrationBinding
basicProfileBinding	basicHttpBinding
Several config names have been simplified
@serviceType on service	type
@bindingSectionName on endpoint	binding
@contractType on endpoint	contract
@configurationName on binding	name
@configurationName on behavior	name
Object Model
Service changes
ServiceHost<T>()	ServiceHost(typeof(T))
ServiceSite	InstanceContext
[InstanceMode=InstanceMode.Singleton]	[InstanceContextMode= InstanceContextMode.Single]
[InstanceMode=InstanceMode.PrivateSession]	[InstanceContextMode= InstanceContextMode.PerSession]
[InstanceMode=InstanceMode.PerCall]	[InstanceContextMode= InstanceContextMode.PerCall]
[InstanceMode=InstanceMode.SharedSession]	[InstanceContextMode= InstanceContextMode.Shareable]
[OperationBehavior(AutoCompleteTransaction= false]	[OperationBehavior(TransactionAutoComplete= false]
[OperationBehavior(AutoEnlistTransaction= false]	[OperationBehavior(TransactionScopeRequired= false]
[BindingRequirements( TransactionFlowRequirements= RequirementsMode.Require)]	[TransactionFlow(TransactionFlowOption.Required)] On the operation
[BindingRequirements( QueuedDeliveryRequirements= RequirementsMode.Require)	[BindingRequirements(QueuedDeliveryRequirements= BindingRequirementsMode.Required)
System.Runtime.Serialization.XmlFormatter is the default formatter. To use the XmlSerializer, apply the XmlSerializerFormat attribute
[ServiceContract(FormatMode=serializer)]	[XmlSerializerFormat]
Client Changes
ProxyBase	ClientBase<T>
IProxyChannel	IClientChannel
Fault Changes
Fault<T>	FaultException<T>
UnknownFault	UnknownFaultException
DataContract
DataMember.IsOptional	DataMember.IsRequired, default is false
Existing code that implements IBodyWriter will need to change to implement BodyWriter.OnWriteBodyContents instead of IBodyWriter.WriteBody
IBodyWriter	BodyWriter
Binding Names changed: Dropped ‘Profile’ and made transport naming consistent
WsProfileBinding	WSHttpBinding
WsProfileDualBinding	WSDualHttpBinding
NetProfileTcpBinding	NetTcpBinding
NetProfileDualTcpBinding	NetTcpBinding
NetProfileNamedPipeBinding	NetNamedPipeBinding
NetProfileMsmqBinding	NetMsmqBinding
MsmqIntegrationBinding	MsmqIntegrationBinding
BasicProfileBinding	BasicHttpBinding

Changing Configuration:

Replace <service serviceType="…"> with <service type="…">
Replace <endpoint contractType="…" bindingSectionName= "…"> with <endpoint contract="…" binding="…">
Replace <behavior configurationName="…"> with <behavior name="…">
Replace <binding configurationName="…"> with <binding name="…">
Replace the old binding names with the new ones. Refer to the table for the new binding names.

You no longer configure a uniquely named security element within a binding configuration. You set the security mode (usually one of Transport, Message, or TransportWithMessageCredential) using binding\security\@mode. Depending on the binding and the selected security mode, you configure the binding\security\message element or the binding\security\transport element.

In the same way, reliableSession is a standard element available under most bindings.

The following is a sample of new configuration:

Here is a sample client config:

For client code, your best bet is to rerun svcutil.

Namespaces

Removed

Microsoft.Tools.Indigo

Microsoft.Transactions.Bridge.Configuration

Microsoft.Transactions.Bridge.Dtc

Microsoft.Transactions.Wsat.Protocol

System.ServiceModel.Diagnostics

System.ServiceModel.QueueHelper

System.ServiceModel.QueueHelper.Design

System.Transactions.Isolation

System.Transactions.Recovery

Added

System.ServiceModel.Install.Configuration

Detail

Detailed API change reports are available here on Omri's blog. They cover:

Beta1 to Nov/05 CTP
Beta 1 to PDC,
PDC to Nov/05 CTP

These reports are not intended for end to end consumption, but rather they offer a reference to help you decipher changes when you know the name of an API in the Beta1, the PDC, or the Nov/05 CTP build.

Update Dec 14, 2005: Added link to detailed list.

Update Dec 20, 2005: Corrected InstanceMode.Shared to be InstanceMode.Shareable