WFC_DotNetWindowsCommunicationFoundation.ppt

WindowsCommunicationFoundation

1. Windows Communication
Foundation (WCF)
Jim Fawcett
CSE775 –Distributed Objects
Spring 2007

2. References
Introducing WCF, David Chappell,
www.davidchappell.com/IntroducingWCFv1.2.1.pdf
–Using three diagrams from this reference
Programming Indigo, David Pallmann, Microsoft
Press, 2005
Pro WCF, Peiris and Mulder, Apress, 2007

3. What is WCF?
Integration of several Microsoft
Technologies:
–Web services (ASMX)
–Web service extensions (WSE)
WS-Security
WS-Reliability
WS-Addressing
–.Net Remoting
–MSMQ messaging
–COM+ Transactions

4. Chappell, ibid, pg 14

5. Channel Model
WCF supports three types of channel
activity:
–Asysnchronous one-way
–Request, wait for reply
–Full duplex two-way

6. Structure
Service
–Contract
Service contract –RPC Interface
Data contract –Type serialization
Message contract –Soap message
–Binding
Transport –HTTP, TCP, MSMQ, …
Channel type –one-way, duplex, request-reply
Encoding –XML, binary, MTOM (msg trans optim mech)
WS-* protocols –WS-Security, …
–Address
http://someURI
net.tcp://someOtherURI
net.msmq://stillAnotherURI

7. Chappell, ibid, pg 25

8. Channel Interfaces
public interface IOutputChannel : IChannel
{ void Send(Message msg); }
public interface IInputChannel : IChannel
{ Message Receive(); }
public interface IDuplexChannel :
IOutputChannel, IInputChannel {}
public interface IRequestChannel : IChannel
{ Message Request(Message msg); }
public interface IReplyChannel : IChannel
{ IRequestContext ReceiveRequest(); }
public interface IRequestContext : Idisposable
{ Message RequestMessage { get; }
void Reply(Message msg); }

9. Service Contract
<%@ ServiceHost Language=“C#”
Service=“MyService” %>
[ServiceContract]
public interface IMyService
{
[OperationContract]
string Hello( string name);
}
public class MyService : IMyService
{
public string Hello(string name)
{ return “Hello “ + name; }
}

10. Hosts
WCF Services can be hosted in:
–Internet Information Services (IIS)
Very similar to web services
–Windows services
Exposing windows service in style of WS
–Console and Winform applications
New style for socket like functionality

11. Monitoring Services
Message Logging
WCF Performance counters
–Calls, CallsOutsantding, CallsErrored, …
–SecurityCallsNotAuthenticated, …
–TxCommitted, TxAborted, …
–RMSessionsStarted, RMSessionsFaulted, …
Windows Management Instrumentation
(WMI), a COM technology

12. Other Topics
WCF Security
–Credentials and claims (evidence)
–Transport-level security
–Message-level security
–Federated security model
–Authorization
–Auditing

13. Reliable Messaging
ReliableSession enabled
–Implemented at the SOAP level not TCP packet
–Very similar to TCP functionality
–Messages not sent are held in a Transfer
Window cache
–Will have problems with large messages
MSMQ Binding
–Needs microsoft platforms on both ends
–Supports store and forward

14. Other Features
WCF Supports transactions
–ACID properties
Atomicity
–composite operations treated as a unit
Consistency
–Operations succeed or the system is returned to prior
state
Isolation
–Each transaction is independent and isolated from other
transactions
Durability
–If an operation succeeds it becomes durable, e.g.,
committed to a database or other persistant store

15. Conclusion
Convergence of programming models
–Desktop Application
–Web Application
–Windows Services
Flexible hosting options
Flexible abstractions