Implement a simple windows communication foundation

Introduction

Windows Communication Foundation, or just WCF, is a programming framework used to build applications that inter-communicate. WCF is the part of the .NET Framework dedicated to communications.

Originally tagged with the code name "Indigo", WCF is one of the four new application programming interfaces introduced with .NET Framework 3.0, which was released in December 2006. The .NET Framework is Microsoft technology that ships in Windows operating systems (client, server and mobile platforms). The .NET Framework v3.0 is included in Windows Vista and Windows Server 2008; It is available as a free download for Windows XP and Windows Server 2003, and a similar but separate version is also available for .NET Compact Framework version 3.5.

Because WCF is part of the .NET Framework, applications that use WCF can be developed in any programming language that can target the .NET runtime.

The WCF programming model unifies the various communications programming models supported in .NET 2.0, into a single model. Released in November 2005, .NET 2.0 provided separate APIs for SOAP-based communications for maximum interoperability (Web Services), binary-optimized communications between applications running on Windows machines (.NET Remoting), transactional communications (Distributed Transactions), and asynchronous communications (Message Queues). WCF unifies the capabilities from these mechanisms into a single, common, general Service-oriented programming model for communications.

Main

Here we will try to define implement a simple WCF to a project called DerivativesCalculator

First step create a visual studio solution then create a c# class project.

Next step is to add a reference for Windows Communication Foundation to the DerivativesCalculatorService Project. It is in add reference -> .NET tab -> System.ServiceModel. Next define the Contract that the Derivatives Calculator Service will Expose. Rename the class file, Class1.cs, in the DerivativesCalculatorService project to IDerivativesCalculator.cs, and modify the content thereof to read as follows:

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.Text;

namespace DerivativesCalculatorService
{
    [ServiceContract]
    public interface IDerivativesCalculator
    {
        [OperationContract]
        Decimal CalculateDerivative(int days, string[] symbols, 
string[] functions);
    }
}

Next is to Implement the Contract that the Derivatives Calculator Service will Expose. Add a class named, Calculator.cs, to the project, and modify its contents to look like this and build the project:

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.Text;

namespace DerivativesCalculatorService
{
    public class Calculator : IDerivativesCalculator
    {
        #region IDerivativesCalculator Members

        decimal IDerivativesCalculator.CalculateDerivative(int days,
 string[] symbols, string[] functions)
        {
            return (decimal)(System.DateTime.Now.Millisecond);
        }

        #endregion
    }
}

You will need to host the Derivatives Calculator Service that you defined and implemented in the first exercise to the .NET executeable. Specifically, you will host the service within a .NET console application.

Add a new console application project called, Host, to the DerivativesCalculator solution. There are 3 reference you must add to this new host project. From .NET tab is System.ServiceModel, System.Configuration, and a reference to the DerivatesCalculatorService project.

Next step is to write the Windows Communication Foundation code needed to provide a host for the Derivatives Calculator service. Modify the Program.cs class in the Host project to read as follows:

using System;
using System.Collections.Generic;
using System.ServiceModel;
using System.Text;
using System.Configuration;
using DerivativesCalculatorService;

namespace Host
{
    public class Program
    {
        public static void Main(string[] args)
        {
            Type serviceType = typeof(Calculator);


            using (ServiceHost host = new ServiceHost(serviceType))
            {
                host.Open();

                Console.WriteLine(
                    "The derivatives calculator service is available."
                );
                Console.ReadKey();
            }

        }
    }
}

Configure this service by add an application configuration file named, app.config, to the Host project in your solution.

<configuration>
  <system.servicemodel>

    <services>
      <service name="DerivativesCalculatorService.Calculator" 
behaviorconfiguration="metadataBehavior">
        <endpoint address="CalculatorService" binding="basicHttpBinding" 
contract="DerivativesCalculatorService.IDerivativesCalculator">
        <endpoint address="mex" binding="mexHttpBinding" 
contract="IMetadataExchange">
        <host>
          <baseaddresses>
            <add baseaddress="http://localhost:8000/Derivatives/">
            <add baseaddress="net.tcp://localhost:8010/Derivatives/">
          </add>
        </add>
      </baseaddresses>
    </host>
    <behaviors>
      <servicebehaviors>
        <behavior name="metadataBehavior">
          <servicemetadata httpgetenabled="true">
        </servicemetadata>
      </behavior>
    </servicebehaviors>
  </behaviors>
</endpoint>
</endpoint></service></services></system.servicemodel>
</configuration>

Test the Service
1. Build the DerivativesCalculator solution.
2. Start a new instance of the Host project.
3. Choose Run from the Windows Start menu, and enter.

http://localhost:8000/Derivatives/
Internet Explorer should open, and display a page like the one in figure below.

You can try to click on the link to http://localhost:8000/Derivatives/?wsdl near the top of the page and examine the page of WSDL that appears. Close Internet Explorer and then you can enter a keystroke into the console application window of the Host executable to terminate the Derivatives Calculator Service.

Next step is to consume the service we have created above. you will build a client that will use the Derivatives Calculator Service above. Add a second new C# Console Application project called, Client, to your solution. Generate a Typed Proxy and Configuration File for the Client Application.

1. Start a new instance of the Host project.
2. Open the Start->Programs->Microsoft Windows SDK->Cmd Shell command prompt.
3. Enter,
cd c:\Windows Communication Foundation\Labs\DerivativesCalculator at the command prompt.
4. Next, enter,
svcutil http://localhost:8000/Derivatives/ /out:Client.cs /config:app.config
5. Choose Debug and Stop Debugging from the Visual Studio menus.

Next Add a reference to the System.ServiceModel .NET assembly, to the Client project. Next is to Code and Configure the Client to Consume this DerivativesCalculator Service. Modift the app.config in Client project like the one below:

<configuration>
    <system.servicemodel>
        <bindings>
            <basichttpbinding>
                <binding name="BasicHttpBinding_IDerivativesCalculator" 
closetimeout="00:01:00" opentimeout="00:01:00" receivetimeout="00:10:00" 
sendtimeout="00:01:00" allowcookies="false" bypassproxyonlocal="false" 
hostnamecomparisonmode="StrongWildcard" maxbuffersize="65536" maxbufferpoolsize="524288" 
maxreceivedmessagesize="65536" messageencoding="Text" textencoding="utf-8" 
transfermode="Buffered" usedefaultwebproxy="true">
                    <readerquotas maxdepth="32" maxstringcontentlength="8192" 
maxarraylength="16384" maxbytesperread="4096" maxnametablecharcount="16384">
                    <security mode="None">
                        <transport clientcredentialtype="None" 
proxycredentialtype="None" realm="">
                        <message clientcredentialtype="UserName" 
algorithmsuite="Default">
                    </message>
                </transport>
            </security>
        </readerquotas>
        <client>
            <endpoint address="http://localhost/DerivativesCalculator/Service.svc" binding="wsHttpBinding" 
contract="IDerivativesCalculator" name="DerivativesCalculatorConfiguration">
        </endpoint>
    </client>
</binding>
</basichttpbinding>
</bindings>
</system.servicemodel></configuration>

Write the code in the Program.cs file of the Client project like the one below:

using System;
using System.Collections.Generic;
using System.Text;

namespace Client
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Press any key when the service is ready.");
            Console.ReadKey();

            DerivativesCalculatorClient proxy = new 
DerivativesCalculatorClient("DerivativesCalculatorConfiguration");
            decimal result = proxy.CalculateDerivative(3, new 
string[] { "MSFT" }, new string[] { });
            Console.WriteLine("Result: {0}", result);

            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();

        }
    }
}

The last step is to have the client consume the DerivativesCalculator Service. Set client project as startup project and run/debug your solution. When you see activity in the console for the Host application, enter a keystroke into the console for the Client application. You should see the client obtain an estimate of the value of a derivative from the Derivatives Calculator service, as shown in below. Note that the value shown in your console may vary from the value shown below, due to variations in prevailing market conditions over time.

Conclusion

You used the Windows Communication Foundation to provide and use a simple service. You saw the flexibility of the options for hosting services, by which services can be hosted in any .NET executable. You also saw how the address and bindings of a service can be altered independently of the code in the service or in its clients, to change the location of a service, and also how it communicates.

References

Include all the useful links or references that can help users learn about this tutorial

1. MSDN Windows Communication Foundation
2. Introduction to Building Windows Communication Foundation Services

Download Source Code

• Download DerivativesCalculator.zip

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