WINDOWS COMMUNICATION FOUNDATION

1
WINDOWS COMMUNICATION FOUNDATION

• www.otssolutions.com

2
Agenda

• Introduction to WCF
• What is it? Why use it?
• Architecture
• Fundamentals and the ABCs of WCF
• Hosting
• Tooling Support
• Handling faults

3
Introduction to WCF
4
What is WCF?

• Stands for Windows Communication Foundation
• One of the 4 pillars of .NET 3.0
• Microsofts unified programming model (the
  service model) for building Service-Oriented
  Applications

5
Different technology combined to form WCF.
6
WCF Architecture
7
SOA

• Service
• Small program interacted by well defines message
  exchanges
• Agile, Reliable, Stable, Interoperable, Secure
• Four Tenets
• Boundaries are Explicit
• Services are Autonomous
• Services share schema and contract, not class
• Service compatibility is based upon policy

8
SOA solutions used
9
SOA Use for Mobile platforms
10
Windows Communication Foundation

• WCF provides
• an SDK for creating SOA
• a runtime for running Services on Windows
• Services send and receive messages
• All messages are SOAP messages
• WCF takes care of all the plumbing

11
Why use WCF?

• Interoperable and Standards based
• Supports WS- protocols
• Unified Programming Model
• Unifies previous models like .NET Remoting, ASMX
  web services, COM etc
• Productive Programming Model
• Declarative
• Imperative
• Configuration based

12
WCF Value Proposition

• Simplicity
• Flexibility
• Maintainability
• Power

13
WCF How does it work?

• SOAP over HTTP
• SOAP over Message Queues
• SOAP over TCP

SOAP Message
Client
Service
SOAP Message
14
WCF End points
A Address (Where) B Binding (How) C
Contract (What)
A
B
C
Client
Service
Message
A
B
C
A
B
C
A
B
C
15
WCF Endpoints

• Every service has
• Address
• Where the service is
• Binding
• How to talk to the service
• Contract
• What the service can do

16
Address

• Combination of transport, server name, port
  path
• Transport is determined by the binding
• Examples
• http//localhost8001
• net.tcp//localhost8002/MyService
• net.pipe//localhost/MyPipe
• net.msmq//localhost/private/MyService
• net.msmq//localhost/MyService

http//server345/Service
17
Bindings

• Transport
• HTTP
• TCP
• MSMQ
• Message formats and encoding
• Plain text
• Binary
• Message Transmission Optimization Mechanism
  (MTOM)
• Communication security
• No security
• Transport security
• Message security
• Authenticating and authorizing callers

18
Out of the box Bindings

• BasicHttpBinding
• WSHttpBinding
• WS2007HttpBinding
• WSDualHttpBinding
• WSFederationHttpBinding
• WS2007FederationHttpBinding

• NetTcpBinding
• NetNamedPipeBinding
• NetMsmqBinding
• NetPeerTcpBinding
• WebHttpBinding
• MsmqIntegrationBinding

19
Contracts

• Service contracts
• Defines operations, communications and
  behaviours.
• Data contracts
• Defines data entities and parameter types.
• Fault contracts
• Defines error types
• Message contracts
• Defines message formats

20
Service Contracts

• ServiceContract Defines a set of operations
• OperationContract Defines a single method

ServiceContract public interface IService
OperationContract string GetData(int
value) public class ConcreteService
IService public string GetData(int value)
... public string OtherMethod()
...
21
Data Contracts

• DataContract Specifies type as a data
  contract
• DataMember Members that are part of contract

DataContract public class CustomType
DataMember public bool MyFlag get set
DataMember public string MyString
get set
22
Alternative DataContract

• DataContract created specifically for WCF to
  serialize types
• Attribute contains Name and Namespace properties
• DataMember is needed to specify which
  properties/fields will form part of the contract
• Contains EmitDefaultValue, IsRequired, Name,
  Order properties

23
Metadata Exchange

• Service can also expose endpoint for Metadata
  Exchange (MEX)
• It provides a mechanism for clients to find out
  about
• Address of other end points
• Bindings that are used
• Contracts used Service, Operation, Data, etc

24
Hosting

• IIS
• HTTP only
• WAS (Windows Activation Service)
• Can use any transport
• Vista and Windows Server 2008 only
• Self hosting
• Can use any transport
• Can be hosted within Console, WinForms, etc
  Applications

25
Tooling Support
26
Tooling Support

• Visual Studio
• Separate projects for WCF
• Add Service reference menu
• WCF Configuration Editor
• WCF Service Host
• WCF Test Tool
• SvcUtil To generate proxies
• SvcTraceViewer To view logs

27
Handling Faults
28
SOAP Faults

• Three main kinds of Exceptions can occur
• Communication errors
• Unexpected error on the service
• Errors thrown by the service on purpose
• .NET Exceptions are technology specific
• All Exceptions come across the wire as SOAP
  Faults

29
Faults

• In WCF, SOAP faults are passed in as
  FaultException objects
• Rather than throwing Exceptions, services should
  throw FaultExceptions
• Or better still FaultExceptionltTgt
• Throwing FaultExceptions will not fault the proxy
  and the channel

30
FaultContracts

• Specifies what kind of Exceptions, an operation
  can throw

ServiceContract public interface
IEmployeeService OperationContract
FaultContract(typeof(ValidationException
)) public void AddEmployee(Employee e)

31
Advantage

• Its made of a lot of different components, so you
  can create new components for security,
  transport, authentication.
• In WCF, there is no need to make much change in
  code for implementing the security model and
  changing the binding. Small changes in the
  configuration will make your requirements.
• Its faster than ASMX
• Its Interoperability, for java, and more.
• WCF is interoperable with other services when
  compared to .Net Remoting, where the client and
  service have to be .Net
• WCF services provide better reliability and
  security in compared to ASMX web services.

32
Disadvantage

• WCF is Microsoft's implementation of SOA and
  hence its APIs are solely controlled by MS which
  makes interoperability a bit difficult.
• To deploy WCF apps, need more underlying hardware
  resources on the platform on which the WCF
  applications will be running, since there is an
  additional layer of abstraction to deal with.

33
Summary

• WCF provides a runtime for creating Service
  Oriented Apps
• Provides a productive programming model. Takes
  care of
• Messaging and Exchange formats
• All Plumbing Transaction, Reliability, Security,
  etc
• Supports Declarative (via attributes), Imperative
  (via code) and Configuration based (via config
  files) programming model
• ABCs of Endpoints
• Address Where to go?
• Binding How to get there?
• Contract What to do?
• Hosting
• IIS, WAS, Self-hosting

34

• Thank You

• http//www.otssolutions.com/

35

• India
• Gurgaon ( Haryana )
• 795, Udyog Vihar, Phase-V
• Gurgaon(Haryana) India
• Ph 91 124 4101350
• 91 124 4748100
• Write to us at sales_at_otssolutions.com

• United kingdom
• 88 Wood Street
• 10th Floor London
• EC2V 7RS
• Ph 44 208 099 1660
• Write to us at sales_at_otssolutions.com

• USA
• 4433 Merlin
• Way , Soquel
• CA 95073
• United States
• Ph 1 408 540 0001
• Write to us at sales_at_otssolutions.com

• http//www.otssolutions.com/