Wenlong Dong's Blog : WCF General

Top WF/WCF Sessions in PDC2008

wdong — Mon, 06 Oct 2008 07:16:00 GMT

There are still 21 days to go until the PDC. Are you excited to attend those fascinating technical sessions? You might have noticed that we have the following interesting sessions for WF/WCF as part of .NET Framework 4.0:

· WF 4.0: A First Look (Kenny Wolf)

· WCF 4.0: Building WCF Services with WF in Microsoft .NET 4.0 (Ed Pinto)

· WF 4.0: Extending with Custom Activities (Matt Winkler)

· WCF 4.0: Developing RESTful Services (Steve Maine)

· WPF/WF 4.0: Declarative Programming Using XAML (Rob Relyea/Daniel Roth)

· WCF: Zen of Performance and Scale (Nicholas Allen)

Through these talks, you will see how Microsoft is refreshing these technologies in the next release in .NET 4.0 by investing heavily on usability, modeling, performance, and scalability. There are also a bunch of other PDC talks which are related to WF/WCF. Enjoy it!

Patterns and Practices: WCF Security Guidance available online

wdong — Fri, 28 Mar 2008 06:56:00 GMT

Here is some good news for people who are looking for WCF Security guidance. The Microsoft Patterns and Practices team has just created the following blog for this:

http://blogs.msdn.com/jmeier/archive/2008/03/27/patterns-and-practices-wcf-security-guidance-now-available.aspx

Here is their root page:

http://www.codeplex.com/WCFSecurity/

How to Use a Singleton WCF Proxy to Call Different Workflow Service Instances in .NET 3.5?

wdong — Thu, 08 Nov 2007 05:03:00 GMT

In .NET 3.5, a new type WorkflowServiceHost is introduced to provide the integration of WF and WCF. On the server-side, ReceiveActivty plays the main role to implement WCF service operations. With this, you can have WCF clients to talk to WF services. Also ContextChannel is introduced to flow the context between the client and the service so that a call to the service from the client can be routed correctly to the right WF instance.

One question that people asked is:

How can we use a single WCF proxy to call different Workflow service instances and flow the context information to the right instances? Is it doable?

Yes, it is doable. By default, the proxy (the context channel) caches the context internally and flows the same context to the service. In order to use the same proxy to flow different contexts, the first step is to disable the context on the IContextManager property of the proxy before it’s opened:

IContextManager contextManager = ((IClientChannel)helloProxy).GetProperty<IContextManager>();

contextManager.Enabled = false;

Now, you can simply attach the context to the ContextMessageProperty property of the outgoing message:

using (OperationContextScope scope = new OperationContextScope( (IContextChannel)helloProxy))

{

ContextMessageProperty property = new ContextMessageProperty(context);

OperationContext.Current.OutgoingMessageProperties.Add( "ContextMessageProperty", property);

helloProxy.Hello("Hello");

}

Below is the sample code that shows how to achieve this. You can see how the client initiates two calls to get two different contexts and then calls the WF service with the contexts interleaved. The sample output is as following:

You said: Hello

You said: Hello 43f5aa31-9b71-4978-9a84-ad19ea727026

You said: Hello

You said: Hello f4962a99-3ec5-4467-8330-a96f0d7aaa21

You said: Hello 43f5aa31-9b71-4978-9a84-ad19ea727026

You said: Hello f4962a99-3ec5-4467-8330-a96f0d7aaa21

You can also store the context data in a file or a database and reconstruct it once you need to connect to the existing WF instance with that context. Here is the code snippet that shows how to reconstruct the context given only the InstanceId (a GUID) data:

// Argument 'contextData' is the InstanceId (a GUID, for example,

// "ad79216c-768f-4f1a-a9b8-3bb6cc512bb4") that you stored earlier

// for the WF instance that you want to reconnect to.

IDictionary<XmlQualifiedName, string> ReconstructContext(string contextData)

{

string contextNamespace = "http://schemas.microsoft.com/ws/2006/05/context";

string contextName = "InstanceId";

XmlQualifiedName xqn = new XmlQualifiedName(contextName, contextNamespace);

Dictionary<XmlQualifiedName, string> context = new Dictionary<XmlQualifiedName, string>();

context.Add(xqn, contextData);

return context;

}

Sample code:

namespace UseContextPerCall

{

using System;

using System.Collections.Generic;

using System.Text;

using System.ServiceModel;

using System.Workflow.Activities;

using System.Workflow.Activities.Rules;

using System.ServiceModel.Channels;

using System.Collections;

using System.Xml;

using System.Workflow.ComponentModel.Compiler;

using System.Workflow.ComponentModel;

using System.ServiceModel.Description;

class Program

{

const string url = "http://localhost/foo/bar.svc";

WorkflowServiceHost serviceHost;

IHelloService helloProxy;

ChannelFactory<IHelloService> factory;

static void Main(string[] args)

{

try

{

Program p = new Program();

p.Start();

}

catch (Exception ex)

{

Exception inner = ex;

while (inner.InnerException != null)

inner = inner.InnerException;

if (inner is WorkflowValidationFailedException)

{

WorkflowValidationFailedException valE = inner as WorkflowValidationFailedException;

for (int i = 0; i < valE.Errors.Count; i++)

{

Console.WriteLine(valE.Errors[i].ErrorText);

}

else

{

Console.WriteLine(inner.ToString());

}

void StartService()

{

serviceHost = new WorkflowServiceHost(typeof(MyWorkflow), new Uri(url));

serviceHost.AddServiceEndpoint(typeof(IHelloService), new WSHttpContextBinding(), "");

ServiceDebugBehavior sdb = serviceHost.Description.Behaviors.Find<ServiceDebugBehavior>();

sdb.IncludeExceptionDetailInFaults = true;

serviceHost.Open();

}

IDictionary<XmlQualifiedName, string> FirstCall()

{

IHelloService proxy = factory.CreateChannel();

Console.WriteLine(proxy.Hello("Hello"));

IContextManager contextManager = ((IClientChannel)proxy).GetProperty<IContextManager>();

IDictionary<XmlQualifiedName, string> context = contextManager.GetContext();

((IClientChannel)proxy).Close();

return context;

}

void Call(IDictionary<XmlQualifiedName, string> context)

{

using (OperationContextScope scope = new OperationContextScope( (IContextChannel)helloProxy))

{

ContextMessageProperty property = new ContextMessageProperty(context);

OperationContext.Current.OutgoingMessageProperties.Add( "ContextMessageProperty", property);

foreach (string val in context.Values)

{

Console.WriteLine(helloProxy.Hello("Hello " + val));

break;

}

void CreateProxy()

{

factory = new ChannelFactory<IHelloService>(new WSHttpContextBinding(), new EndpointAddress(url));

helloProxy = factory.CreateChannel();

// Disabling default context switching

IContextManager contextManager = ((IClientChannel)helloProxy).GetProperty<IContextManager>();

contextManager.Enabled = false;

((IClientChannel)helloProxy).Open();

}

void Clenaup()

{

if (helloProxy != null)

{

((IClientChannel)helloProxy).Abort();

}

if (factory != null)

{

factory.Abort();

}

serviceHost.Abort();

}

void Start()

{

StartService();

CreateProxy();

IDictionary<XmlQualifiedName, string> context = FirstCall();

Call(context);

IDictionary<XmlQualifiedName, string> context1 = FirstCall();

Call(context1);

// Intermixed

Call(context);

Call(context1);

Clenaup();

}

[ServiceContract]

interface IHelloService

{

[OperationContract]

string Hello(string message);

}

public class MyWorkflow : SequentialWorkflowActivity

{

public MyWorkflow()

{

ReceiveActivity receiveActivity = new ReceiveActivity("HelloReceive");

receiveActivity.CanCreateInstance = true;

receiveActivity.ServiceOperationInfo = new TypedOperationInfo(typeof(IHelloService), "Hello");

CodeActivity codeActivity = new CodeActivity("HelloCode");

codeActivity.ExecuteCode += new EventHandler(codeActivity_ExecuteCode);

receiveActivity.Activities.Add(codeActivity);

WhileActivity whileActivity = new WhileActivity("HelloWhile");

CodeCondition condition = new CodeCondition();

condition.Condition += new EventHandler<ConditionalEventArgs>(condition_Condition);

whileActivity.Condition = condition;

whileActivity.Activities.Add(receiveActivity);

// adding binding

ActivityBind activityBindArg = new ActivityBind("MyWorkflow");

activityBindArg.Path = "HelloArg1";

WorkflowParameterBinding bindingArg1 = new WorkflowParameterBinding("message");

bindingArg1.SetBinding(WorkflowParameterBinding.ValueProperty, activityBindArg);

ActivityBind activityBindReturn = new ActivityBind("MyWorkflow");

activityBindReturn.Path = "HelloResult";

WorkflowParameterBinding bindingResult = new WorkflowParameterBinding("(ReturnValue)");

bindingResult.SetBinding(WorkflowParameterBinding.ValueProperty, activityBindReturn);

receiveActivity.ParameterBindings.Add(bindingArg1);

receiveActivity.ParameterBindings.Add(bindingResult);

this.Activities.Add(whileActivity);

}

public static readonly DependencyProperty HelloArg1Property = DependencyProperty.Register(

"HelloArg1",

typeof(string),

typeof(MyWorkflow),

new PropertyMetadata(DependencyPropertyOptions.Default));

public string HelloArg1

{

get

{

return (string)base.GetValue(MyWorkflow.HelloArg1Property);

}

set

{

base.SetValue(MyWorkflow.HelloArg1Property, value);

}

public static readonly DependencyProperty HelloResultProperty = DependencyProperty.Register(

"HelloResult",

typeof(string),

typeof(MyWorkflow),

new PropertyMetadata(DependencyPropertyOptions.Default));

public string HelloResult

{

get

{

return (string)base.GetValue(MyWorkflow.HelloResultProperty);

}

set

{

base.SetValue(MyWorkflow.HelloResultProperty, value);

}

void condition_Condition(object sender, ConditionalEventArgs e)

{

e.Result = true;

}

void codeActivity_ExecuteCode(object sender, EventArgs e)

{

this.HelloResult = "You said: " + this.HelloArg1;

}

Come and join the Connected Framework development team!

wdong — Thu, 08 Nov 2007 02:22:00 GMT

Do you want to work on Microsoft's next generation of the distributed application framework? Do you enjoy the thrill of shipping a great product? Do you want to join the team that has shipped WCF + WF in .NET 3.0? Are you up to the challenge of improving and optimizing performance of the .NET Framework that impacts millions of customers? If your answer are yes, this is a fantastic opportunity for you:

http://members.microsoft.com/careers/search/details.aspx?JobID=E32F6A1B-B495-41D0-AF22-7AC742B0EDB2

A simple config-less IIS-hosted WCF service

wdong — Fri, 17 Aug 2007 07:18:00 GMT

I feel that it’s pretty handy to have a simple config-less IIS-hosted WCF service when I want to check whether WCF is correctly configured in IIS. So I post such a service here just for convenience.

Simple.svc:

<% @ServiceHost Language="c#" Factory="HelloWorld.SimpleServiceHostFactory" %>

namespace HelloWorld

{

using System;

using System.ServiceModel;

using System.ServiceModel.Activation;

using System.ServiceModel.Channels;

using System.ServiceModel.Description;

public class SimpleServiceHostFactory : ServiceHostFactory

{

public override ServiceHostBase CreateServiceHost(string service, Uri[] baseAddresses)

{

ServiceHost serviceHost = new ServiceHost(typeof(SimpleService), baseAddresses);

serviceHost.AddServiceEndpoint(typeof(ISimpleContract), new BasicHttpBinding(), "");

// Enable HttpGet for the service

ServiceMetadataBehavior metadata = new ServiceMetadataBehavior();

metadata.HttpGetEnabled = true;

serviceHost.Description.Behaviors.Add(metadata);

return serviceHost;

}

[ServiceContract(Namespace="http://www.microsoft.com/test")]

public interface ISimpleContract

{

[OperationContract]

string Hello(string greeting);

}

[ServiceBehavior(InstanceContextMode = InstanceContextMode.Single,

ConcurrencyMode=ConcurrencyMode.Multiple)]

[AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]

class SimpleService : ISimpleContract

{

private int state = 0;

public SimpleService() { }

public string Hello(string greeting)

{

state ++;

return string.Format("[{0}] You said: {1}", state, greeting);

}

Here is the client code:

Client.cs:

using System;

using System.Collections.Generic;

using System.Text;

using System.ServiceModel;

using System.ServiceModel.Channels;

namespace HelloWorldClient

{

[ServiceContract(Namespace="http://www.microsoft.com/test")]

public interface ISimpleContract

{

[OperationContract]

string Hello(string greeting);

}

class Program

{

static void Main(string[] args)

{

try

{

ChannelFactory<ISimpleContract> channelFactory =

new ChannelFactory<ISimpleContract>(new BasicHttpBinding());

ISimpleContract proxy = channelFactory.CreateChannel(new

EndpointAddress("http://localhost/Simple.svc"));

Console.WriteLine(proxy.Hello("Hello"));

}

catch (Exception ex)

{

Console.WriteLine(ex.ToString());

}

To complete this little sample, let’s also provide a simple compiler script on 32-bit box:

%windir%\Microsoft.Net\Framework\v2.0.50727\csc.exe /debug+ /out:Client.exe /target:exe /r:System.ServiceModel.dll /r:System.Web.dll client.cs

How to skip server certificate validation error when using HTTPS?

wdong — Fri, 17 Aug 2007 06:54:00 GMT

When you are developing a WCF service with an HTTPS endpoint (i.e., you enabled Transport security), you would want to test it with a test certificate or a certificate which has some invalid data. The former can happen when you create the certificate with the tool MakeCert.exe. The latter can happen when you use the host name “localhost” instead of the one that matches the subject of the certificate. In this case, you would need to skip the certificate validation error during service development cycle. To skip the error, the simplest thing is to register to the static System.Net API ServicePointManager.ServerCertificateValidationCallback. Here is a short example:

public static void Main(string[] args)

{

System.Net.ServicePointManager.ServerCertificateValidationCallback += new System.Net.Security.RemoteCertificateValidationCallback(

RemoteCertValidate);

// Invoking the service over HTTPS

// ...

}

static bool RemoteCertValidate(object sender, X509Certificate cert, X509Chain chain, System.Net.Security.SslPolicyErrors error)

{

System.Console.WriteLine("WARNING: Got server certificate error: {0}", error);

if (string.Compare(cert.Subject, "CN=FooCertificate") == 0)

{

// NOTE: This should be only used for development phase. You need to remove it in the deploymnet environment!

return true;

}

return false;

}