1. 1
Introduction to WCF Services

2. Objectives

Describe Windows Communication Foundation (WCF)
and service-oriented development with WCF

Explain the procedure to create and host a WCF service
using Visual Studio 2008

Explain the procedure to consume a WCF service using
Visual Studio 2008
 Describe programmatic configuration of applications to
host and call a WCF service

Explain deployment of WCF services
Introduction to WCF Services / Session 1 2

3. Introduction
 Service Oriented Architecture (SOA):
Real World Example of SOA-based application

Is an approach to create enterprise applications
 Integrates existing business components
 Exposes the application to your business partners

Addresses and accommodates changes easily

Helps heterogeneous platforms and applications
communicate with each other
 Exposes the logic of an application as a service
without letting others know about the actual code
Introduction to WCF Services / Session 1 3

4. SOA
 In SOA:

The server machine or the server program hosts the
code
 The server machine or the server program exposes
the code to the clients as a service

Any enterprise application is built using the three
building blocks:

Code

Server Program

Client Program
Introduction to WCF Services / Session 1 4

5. Windows Communication Foundation (WCF)

WCF:
 Is an important part of the Microsoft .NET Framework architecture
 Is a SOA-based technology to create distributed enterprise applications
 Includes features like multiple protocol support, reliability, and security
 Offers interoperability with other services

WCF key components include:
 Service Class
 WCF Runtime
 Host Application
 Service class is the actual business logic exposed as a WCF service
 WCF runtime serves any class as a WCF service
 The class should implement an interface with the ServiceContract
attribute

Host application hosts the WCF runtime
Introduction to WCF Services / Session 1 5

6. WCF Architecture 1-3

The following figure shows the WCF architecture:

 architecture application hosts a service
client host includes:
The host application hosts the WCF runtimeclass through multiple
Theserviceapplication communicates with the server application
endpoints host application
A service
through the proxy class

 A This service class will be exposed as a WCF service
client application
Introduction to WCF Services / Session 1 6

7. WCF Architecture 2-3
Channels: the URL at which the server provides the service
Address is
Endpoint:
A dispatcher component:


Are a helper component client communicates with the service
Specifies the following:
Is processing units
Is a combination of address, binding, and contract
  

Binding describes howservice class on the server
the

 
Acts How componentson the server machine and takes the service request
Commonlyhostclientasof WCF

as if to isreferred ABC
Are inbuilt it a a
application

Contract on athecan beofthe server theprocess inputnext toservicemessage is

 Information reply specified in to the channel or output message
 Passes client and functionalitycode and configuration file
describes the the server to provided by the it. The
Exist The protocol to be used for communication
passed through a series of channels, till it reaches the client
Introduction to WCF Services / Session 1 7

8. WCF Architecture 3-3
 The WCF runtime exposes any class as a WCF service class
provided:
 The class implements an interface with the
ServiceContract attribute

The WCF runtime exposes a method declared in an interface
only with the OperationContract attribute
 The client application talks to the service application through
the proxy class
 The client can choose to interact with the interface directly
instead of using the proxy class
 In the figure, the proxy class:
 Forms a message on behalf of the client application
 Passes the message on to the server
Introduction to WCF Services / Session 1 8

9. Describing the WCF Service
 The WCF runtime:

Exposes and controls a class as the WCF service

Is represented in the System.ServiceModel namespace that
resides inside the System.ServiceModel.dll library

Is hosted in the host process that acts as a server application
 This server application can be:

The EXE assemblies created using the console-based application,
Windows-based application, and Windows service

IIS or Windows Activation Service

The WCF service class hosted in an application other than IIS
is called self-hosted WCF service
Introduction to WCF Services / Session 1 9

10. Creating and Hosting a WCF Service using Visual Studio 2008
 To create and host a WCF service in Visual Studio
2008, you need to create a:

Service interface
 Service class
 Server alias host application
Introduction to WCF Services / Session 1 10

11. Creating a Service Interface 1-2
 The service interface describes the functionality offered
by the server:
Syntax
namespace <namespace Name>
{
[ServiceContract]
public interface <interface Name>
{
[OperationContract]
<return type><Function Name> (Parameters …);
[OperationContract]
<return type><Function Name> (Parameters …);
. .
. .
}
}
Introduction to WCF Services / Session 1 11

12. Creating a Service Interface 2-2
 The code shows a simple IHello service interface:
Snippet
namespace MyService
{
[ServiceContract]
public interface IHello
{
[OperationContract]
string SayHello(string inputMessage);
}
}

In order to use the code, you need to import the
System.ServiceModel namespace from
System.ServiceModel.dll
Introduction to WCF Services / Session 1 12

13. Creating a Service Class 1-2

A service class implements the functionality declared in the service interface:
Syntax
namespace <namespace Name>
{
public class<class Name>:<interface Name>
{
public <return type><Function Name> (Parameters)
{
// Actual functionality related code
return <return value>;
}
public <return type><Function Name> (Parameters)
{
// Actual functionality related code
return <return value>;
}
}
}
Introduction to WCF Services / Session 1 13

14. Creating a Service Class 2-2

In the code, the service class, HelloService, implements the
IHelloService interface:
Snippet
namespace MyService
{
public class HelloService: IHello
{
public string SayHello(string inputMessage)
{
return "Hello " + inputMessage;
}
}
}
 In order to use the code, you need to import the System.ServiceModel
namespace from System.ServiceModel.dll
Introduction to WCF Services / Session 1 14

15. Creating a Server or Host Application 1-7

After creating the service class, you need to create a host application

You can host the WCF service class on:
 IIS
 Custom host application

You need to specify the Address, Binding and Contract (ABC) information
 Generally, ABC information is written in XML-based configuration files
 If the service class is IIS hosted, then the host application uses web.config
file

If the service class is self-hosted, then the host application uses app.config
file
 The host application needs to know the following:
 Which service interface functionality should be offered to the client?
 Which protocol should be used?
 What is the information regarding input/output parameters?

How to start listening requests from the client applications?
Introduction to WCF Services / Session 1 15

16. Creating a Server or Host Application 2-7
<?xml version="1.0" encoding="utf-8" ?>
Syntax
 The syntax for the configuration file is as follows:
<configuration>
<system.serviceModel>
<services>
<service name="<Fully Qualified Name of the Service Class>">
<endpoint
address="<URI where the service needs to accessed>"
binding="<way how service needs to be accessed>"
contract="<Fully Qualified Name of the Interface – defines what is offered
from the service>"/>
<other endpoints>
</service>
</services>
<behaviors>
<serviceBehaviors>
<behavior>
<serviceMetadata httpGetEnabled="true"/>
</behavior>
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
Introduction to WCF Services / Session 1 16

17. Creating a Server or Host Application 3-7
Snippet <service name="MyService.HelloService">
<?xml version="1.0"?> informs the WCF runtime that the

The following code showsasaa sample code class needsthe
<configuration>
<system.serviceModel>
MyService.HelloService
exposed WCF service
inside to be
app.config file
<services>
<service name="MyService.HelloService">
 To use the code, you need to reference
<endpoint address="http://localhost:9898/HelloService"
binding="basicHttpBinding"
System.ServiceModel.dll contract="MyService.IHello"/>
</service>
binding="basicHttpBinding"
address=http://localhost:9898/
</services> informs the WCF runtime that the HTTP
HelloService informs the WCF runtime
contract="MyService.IHello" communicate and ask be used
that the client will no security needs to for
protocol with
for communication
informs the WCF runtime that only the the port number 9898.
<behaviors> HelloService at
<serviceBehaviors>
MyService.IHello kind of
<behavior>
functionality needs to be exposed from
<serviceMetadata httpGetEnabled="true"/>
the MyService.HelloService
</behavior>
class
</serviceBehaviors>
</behaviors>
</system.serviceModel>
</configuration>
Introduction to WCF Services / Session 1 17

18. Creating a Server or Host Application 4-7
 Consider a console application as a server
application

This means that you are hosting the WCF service on
your own server, that is, the console application
 This refers to self-hosting
 Consider that this server listens to the client
requests for the HelloService WCF service
Introduction to WCF Services / Session 1 18

19. Creating a Server or Host Application 5-7
 The code shows how the server listens to the client requests

Note that this code should be written inside the main method of
the server
Snippet
ServiceHost host = new
ServiceHost(typeof(MyService.HelloService));
host.Open();
 In order to use the code, you need to import the
System.ServiceModel namespace from
System.ServiceModel.dll

In the code, a call to Open() method creates and opens the
listener for the service
Introduction to WCF Services / Session 1 19

20. Creating a Server or Host Application 6-7
 In the IIS-hosted WCF service, the ServiceHost
object used in the previous code is replaced with a file
that has the extension .SVC

A directive called @ServiceHost represents the
entire code
 The syntax to use the @ServiceHost directive in
the .SVC file is as follows:
Syntax
<%@ ServiceHost Language=”C#” Service=”<name of service
class which implements functionality >" CodeBehind="<File
which contains service class>" %>
Introduction to WCF Services / Session 1 20

21. Creating a Server or Host Application 7-7

The code shows a @ServiceHost directive in the HelloService.SVC
file while you host MyService.HelloService

To use the code, you need to add the reference to
System.ServiceModel.dll
Snippet
<%@ ServiceHost Language="C#" Debug="true"
Service="MyService.HelloService"
CodeBehind="HelloService.svc.cs" %>

The Service property informs the WCF runtime that when a call is given to
the HelloService.SVC file, it should create an object of the
MyService.HelloService class and serve it to the client

The CodeBehind property informs the WCF runtime about the file in which
the MyService.HelloService class is defined
Introduction to WCF Services / Session 1 21

22. Consuming the WCF service using Visual Studio 2008
 You can call the WCF service functionality hosted on the server
using:
 The service interface in combination with a mediator

The mediator communicates on behalf of the client with the
service that is represented by a class called ChannelFactory
 The Service Reference option in Visual Studio
 The SVCUTIL.EXE utility that ships with the .NET framework

When you use the SVCUTIL.EXE utility or the Service Reference
option, a proxy class is created
 To share only the interface library with the client, you can use
the ChannelFactory class
Introduction to WCF Services / Session 1 22

23. ChannelFactory 1-5
 To access a WCF service hosted on the server by using
ChannelFactory:

In the client application, add a reference to the service
interface library
 Add app.config configuration file in the client
application
Introduction to WCF Services / Session 1 23

24. ChannelFactory 2-5
 The syntax adds the client-side app.config configuration file:
Syntax
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<system.serviceModel>
<client>
<endpoint
address="<URI where the service needs to accessed>"
binding="<way how service needs to be accessed>"
contract="<Fully Qualified Name of the Interface –
defines what
is offered from the service>"
name="<Name_For_the_Configuration>"/>
</client>
</system.serviceModel>
</configuration>
Introduction to WCF Services / Session 1 24

25. ChannelFactory 3-5
 The code shows the code in the app.config configuration file for
the HelloService WCF service:
Snippet
<?xml version="1.0"?>
<configuration>
<system.serviceModel>
<client>
<endpoint
address="http://localhost:9898/HelloService"
binding="basicHttpBinding"
contract="MyService.IHello"
name="MyEndPoint"/>
</client>
</system.serviceModel>
</configuration>
Introduction to WCF Services / Session 1 25

26. ChannelFactory 4-5
 The syntax to use the service interface and create an object is as
follows:
Syntax
<Interfacereference>= new ChannelFactory<Interface
Type>("<Name_For_the_Configuration>").CreateChannel();
Introduction to WCF Services / Session 1 26

27. ChannelFactory 5-5
 The code shows how to use ChannelFactory to call the
HelloService WCF service

You need to import the System.ServiceModel namespace
from System.ServiceModel.dll
Snippet
IHello obj = new ChannelFactory<IHello>("
MyEndPoint").CreateChannel();
Console.WriteLine(obj.SayHello("WCF"));
 Call the CreateChannel() method
Introduction to WCF Services / Session 1 27

28. The Service Reference Option

To access the WCF service hosted on the server by
using the Service Reference option in Visual Studio,
follow these steps:
1. Ensure that the server application is running
2. In the client application, in the Solution Explorer window, right-
click References and click Add Service Reference. The Add
Service Reference window is displayed
3. To call the service, in the Address text box, type the URL
4. To hold the proxy class, in the Namespace textbox, type the
namespace name
5. To add the proxy, click OK
6. Create a proxy class object and call the Web method
Introduction to WCF Services / Session 1 28

29. Using the SVCUTIL.EXE Utility 1-2
 To create a proxy class and access the WCF service
using the SVCUTIL.EXE utility, perform the following
steps:
1. Ensure the server application is running
2. Click Start Programs Microsoft Visual Studio 2008 Visual
Studio Tools Visual Studio 2008 Command Prompt
3. Use the following syntax to use the SVCUTIL.EXE utility
Syntax
SVCUTIL /Config:App.Config /Out:<Proxy Class File Name>
“<type the URL with which the service can be called >”
The code shows how to use the SVCUTIL command to
generate the proxy class and the configuration file for
HelloService WCF service
Snippet
SVCUTIL /Config:App.Config /Out:proxy.cs
“http://localhost:9898/HelloService”
Introduction to WCF Services / Session 1 29

30. Using the SVCUTIL.EXE Utility 2-2
4. Press Enter. This generates two files, the proxy class file and the
app.config configuration file
5. Add the generated files, the proxy class file and the app.config file
to the client application
6. Call the WCF service using the proxy class object (generated in Step
4)
Introduction to WCF Services / Session 1 30

31. Deploying a WCF Service 1-2

The following figure displays different types of host applications
host a WCF service:  IIS 6.0 only supports HTTP protocol
 IIS 7.0 supports TCP and HTTP
protocols

The service hosted using the following
is called the self-hosted WCF service:
 Windows application
 Console application
 Windows service
Introduction to WCF Services / Session 1 31

32. Deploying a WCF Service 2-2

The table shows various hosting environments and the
protocols that each environment supports:
Hosting Environment Supported Protocols
Windows or Console application HTTP, net.tcp, net.pipe,
net.msmq
Windows service application HTTP, net.tcp, net.pipe,
net.msmq
Web Server IIS6 HTTP
Web Server IIS7 - Windows Process HTTP, net.tcp, net.pipe,
Activation Service (WAS) net.msmq
Introduction to WCF Services / Session 1 32

33. Summary

WCF is a SOA-based technology from Microsoft for distributed enterprise
application development

A WCF service class implements an interface with the
[ServiceContract] attribute and exposes the methods with the
[OperationContract] attribute

The server application hosts a WCF service class and offers the functionality
of the class as a service to the clients

WCF services can be self-hosted or IIS hosted

A client determines the functionality offered by the server using the interface
or the proxy class

A client requests the functionality from a WCF service using the
ChannelFactory class, the proxy class, or the SVCUTIL.EXE utility
 The client and server configuration can be written either in code or in
configuration files
Introduction to WCF Services / Session 1 33