Overview

1. Visual Studio provides various WCF project templates – To help you create server-side WCF applications.
2. We’ll use the following project templates in this chapter:
   • For the service itself: WCF | WCF Service Library.
   • To host the service in IIS: WCF | WCF Service Application.
3. To consume a WCF service, you can generate a proxy type based on metadata for a service:
   • Within Visual Studio: “Add Service Reference”.
   • Or at VS command line: Use svcutil.exe.

1. Creating a WCF Service Library:
   • To create a new WCF Service Library:
     • Project type: WCF Service Library.
     • Project name: TempConverterServiceLibrary.
     • Solution name: IISHostedDemo.
       
2. Modifying the BoilerPlate code:
   • Visual Studio generates boilerplate code for a service:
     • Service interface and implementation class.
     • Let’s modify the code as follows:Let’s refactor the generated service interface and class.
       [ServiceContract(Namespace="urn:myNamespace")]
public interface ITempConverter
{
  [OperationContract]
  double CtoF(double c);
  [OperationContract]
  double FtoC(double f);
}


public class TempConverter : ITempConverter
{
  public double CtoF(double c)
  { return (c * 9.0 / 5.0) + 32; }
  public double FtoC(double f)
  { return (f - 32) * 5.0 / 9.0; }
}

       Default namespace: https://tempuri.org.
       Default svc name: interface name.
       Only methods annotated with [OperationContract] are visible to clients, default operation name is method name
       Implementation class implements service interface (implicit or explicit).
     • View code file.
     • View code file.
3. Testing the service at design time:
   • The project contains a config file that can describe the service – Note: WCF 4.* also has lots of sensible defaults to simplify config.
   • This allows us to test the service at design time:
     • Hit Ctrl+F5 to build and run the project.
     • Launches the WCF Test Client.
       

Overview

1. There are 3 ways to host a WCF service:
   • IIS.
   • Windows Activation Service (WAS) in IIS 7/8.
   • Self-hosted.
2. We’ll explore the IIS-hosting option…

1. Creating a WCF Service Application:
   • Add a WCF Service Application project to host WCF service:
     • Project type: WCF Service Application.
     • Project name: MyHostApp.
       
2. Configuring the host application:
   • Configure the host application as follows: In Properties window, use specific port for VS Development Server –
     
   • Delete unnecessary starter code:
     • Delete IService1.cs and Service1.svc.cs.
     • (You could have defined/implemented the service here, but don’t!).
   • Modify the .svc file (which identifies the target service):
     • Rename Service1.svc to TempConverterService.svc.
     • Modify the file as follows.
       <%@ ServiceHost Language="C#"
       Service="TempConverterServiceLibrary.TempConverter" %>

     • View code file.
   • Add a reference to the service library assembly:
     • The service host need this, so it can instantiate the service.
   • In Web.config, you can explicitly specify service endpoints:
     • Define a <service> element for the service.
     • Add <endpoint> element(s) for the service.
   • Optionally, expose a Metadata Exchange (MEX) endpoint:
     • Allows client to auto-generate proxy types.
       <system.serviceModel>
 <services>
  <service name="TempConverterServiceLibrary.TempConverter" >
   <endpoint address=""
        binding="wsHttpBinding"
        contract="TempConverterServiceLibrary.ITempConverter" />
   <endpoint address="mex"
        binding="mexHttpBinding"
        contract="IMetadataExchange"/>
  </service>
 </services>
 ...
</system.serviceModel>

3. Testing the Hosted Service:
   • To test the hosted service:
     • Set the host application as the startup project.
     • Run the solution, and open the .svc file in the browser.
     • Visual Studio creates a test Web page for the .svc file.
       
4. Viewing the WSDL for the Service – Click the link on the test page, to view the WSDL for the service –
   

Overview

1. To access a service from a client – You need a proxy object.
2. If the service publishes its metadata:
   • Generate a proxy type (Add Service Reference, or run SvcUtil).
   • In code, create proxy object and invoke methods.
3. If the service doesn’t publish its metadata:
   • Add a client-side version of service contract.
   • In code, create proxy object using WCF APIs and invoke methods.

1. Generating a proxy class using VS:
   • Add a client application to your solution:
     • E.g. add a Console Application named MyClientApp.
   • In your client application:
     • Add a Service Reference.
     • Specify service address.
     • Generates client-side
       proxy class and interface
       for a particular service
       contract.
       
2. Implementing the client application:
   • In the client code:
     • Create a proxy object:
       • If config file only has 1 service endpoint, you can omit endpoint name in ctor.
       • Otherwise, you must specify service endpoint in ctor.
     • Invoke methods:
       • Synchronous, blocking calls.
     • Close proxy object when you’re finished (why?):
       • Via Close() or Dispose() method.

     using MyClientApp.TempConverterServiceReference;
namespace MyClientApp
{
 class Program
 {
  static void Main(string[] args)
  {
   using (TempConverterClient proxy = new TempConverterClient())
   {
    double f = proxy.CtoF(100);
    Console.WriteLine("100C = {0}F", f);
   }
   ...


     • View code file.
3. Running the applications:
   • Set the start-up projects for your solution as follows –
     
   • Then run your solution:
     • Runs the host program, to host your service.
     • Also runs the client program, to consume the service.