Presentation 24:Windows Communication Foundation

Introduced

Objektorienteret Netværkskommunikation

Introducing WCF

• Windows Vista => .NET Framework 3.0• Also for Windows XP, 2003 Server & 2007• Not Windows Mobile / Windows CE

• Unified Service-Oriented Programming Model

• Replaces / Suplements • .NET Remoting• DCOM• ASP.NET Web services• MSMQ (Queued Messaging) • .NET Enterprise Services

• Protocol Neutrality and Flexibility

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/wcfroadmap.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/wcfarch.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/wcfroadmap.asp http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnlong/html/wcfarch.asp

Learning WCF

• WCF much like .NET Remoting / ASP.NET WS

• Easier / More extensive

• ITONK will adress key issues of WCF

WCF Basic Concepts

• Remote system (like .NET Remoting) is:• Exchanging Messages

• Using Channels, consisting of

• Encodeders• Transports

• Also called the Channel layer

• On top of this is the Service Model Layer

WCF Architecture

Channels

• Channels is chain of stacks • Much like .NET Remoting• Sending messages, being encoded and transported

Messages

• WCF Applications Exchanges Messages• Modelled on SOAP messages

• Envelope, header, body

• Adressing

• Messages are smallest unit of transmission• Messsages have a SOAP and addressing version

Messages

• Message Exchange Pattern (MEP)• One way, request, response, duplex

Channels

• Messages are payload• Channels provide transmission stream• Protocol channels

• Independent of transport

• Extensible

• Transport channels• HTTP, TCP, MSMQ, P2P, Named Pipes

• Extensible

Encoders

• Text (XML, interop) • JSON/POX (XML or JSON, interop)• MTOM (XML with binary part, interop)• Binary (non-interop)

Service Model Layer

• Channel Layer may be used alone – but low level• Service Model Layer

• Build on top of Channel Layer

• .NET Typed layer

• Uses object serialization to generate message XML

Endpoints

• Applications communicates through endpoints• Endpoints defined by WCF ABC

• Address (where is the service)

• Binding (which transport and encoding to use)

• Contract (what operations are available)

Contracts

• Uses annotated .NET interfaces

Contracts

• Like in ASP.NET – only expose explict annotated operations

Bindings

• Many Bindings:

• Interopable• basicHttpBinding• webHttpBinding• wsHttpBinding, wsFederationHttpBinding

• WCF Specific• netTCPBinding• netPeerTcpBinding• netNamedPipeBinding• netMsmqBinding

• MSMQ interop• MsmqlIntegrationBinding

• Extensible (write your own)

WCF Bindings Matrix

Choose your Binding

• Before – you had to choose different middlewares• Now – just choose different bindings

Hosting Services

• Two models supported• Self-hosting: own process (console, winform)

• WAS hosting

• Windows Activation Service• Supported by IIS7• Emulated for IIS6 for HTTP/S

Self-hosting

• Make a ServiceHost, Add Endpoints, Call Open

Creating a Client

• Dynamic Proxies supported (like .NET Remoting)• Use ChannelFactory for this

Specify Endpoint in Config file

Behaviors

• Behaviors can be used to affect the internals of WCF• Eg. Transaction Flow

• Has nothing to do with the wire• Many build-in behaviors, but extensible for own • Attributes can be used [ServiceBehavior],

[OperationBehavior]• Configuration file defined behaviors• Code defined behaviors

Meta Data

• Two ways of sharing contracts• WSDL or Shared Contract DLL

Creating Static Proxies

• Unlike .NET Remoting, which only supports dynamic proxy generation there is also static gen. in WCF

• Or ”Add Service Reference” in VS

Defining the Contract

using System.ServiceModel;

//a WCF contract defined using an interface[ServiceContract]public interface IMath{ [OperationContract] int Add(int x, int y);}

using System.ServiceModel;

//a WCF contract defined using an interface[ServiceContract]public interface IMath{ [OperationContract] int Add(int x, int y);}

//the service class implements the interfacepublic class MathService : IMath{ public int Add(int x, int y) { return x + y; }}

//the service class implements the interfacepublic class MathService : IMath{ public int Add(int x, int y) { return x + y; }}

Implementing the Servicepublic class WCFServiceApp{ public void DefineEndpointProgrammable() { //create a service host for MathService ServiceHost sh = new ServiceHost(typeof(MathService));

//use the AddEndpoint helper method to //create the ServiceEndpoint and add it //to the ServiceDescription sh.AddServiceEndpoint( typeof(IMath), //contract type new WSHttpBinding(), //one of the built-in bindings "http://localhost/MathService/Ep1"); //the endpoint's address

//create and open the service runtime sh.Open();

}

public void DefineEndpointInConfig() { //create a service host for MathService ServiceHost sh = new ServiceHost (typeof(MathService));

//create and open the service runtime sh.Open();

}}

public class WCFServiceApp{ public void DefineEndpointProgrammable() { //create a service host for MathService ServiceHost sh = new ServiceHost(typeof(MathService));

//use the AddEndpoint helper method to //create the ServiceEndpoint and add it //to the ServiceDescription sh.AddServiceEndpoint( typeof(IMath), //contract type new WSHttpBinding(), //one of the built-in bindings "http://localhost/MathService/Ep1"); //the endpoint's address

//create and open the service runtime sh.Open();

}

public void DefineEndpointInConfig() { //create a service host for MathService ServiceHost sh = new ServiceHost (typeof(MathService));

//create and open the service runtime sh.Open();

}}

Create the Service EndpointProgrammatically

Create the Service EndpointProgrammatically

Create the Service Endpoint

Using a ConfigurationFile (see next slide)

Create the Service Endpoint

Using a ConfigurationFile (see next slide)

Configuration File

<!-- configuration file used by above code --><configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0"> <system.serviceModel> <services> <!-- service element references the service type --> <service type="MathService"> <!-- endpoint element defines the ABC's of the endpoint --> <endpoint address="http://localhost/MathService/Ep1" binding="wsHttpBinding" contract="IMath"/> </service> </services> </system.serviceModel></configuration>

<!-- configuration file used by above code --><configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0"> <system.serviceModel> <services> <!-- service element references the service type --> <service type="MathService"> <!-- endpoint element defines the ABC's of the endpoint --> <endpoint address="http://localhost/MathService/Ep1" binding="wsHttpBinding" contract="IMath"/> </service> </services> </system.serviceModel></configuration>

Implementing the Client Using Static Proxy

//this class is generated by svcutil.exe//from the service's metadata//generated config is not shown herepublic class MathProxy : IMath{ ...}

public class WCFClientApp{ public void SendMessageToEndpoint() { //this uses a proxy class that was //created by svcutil.exe from the service's metadata MathProxy proxy = new MathProxy();

int result = proxy.Add(35, 7);

proxy.Close(); }

//this class is generated by svcutil.exe//from the service's metadata//generated config is not shown herepublic class MathProxy : IMath{ ...}

public class WCFClientApp{ public void SendMessageToEndpoint() { //this uses a proxy class that was //created by svcutil.exe from the service's metadata MathProxy proxy = new MathProxy();

int result = proxy.Add(35, 7);

proxy.Close(); }

Implementing the Client Using Dynamic Proxy

public class WCFClientApp{

public void SendMessageToEndpointUsingChannel() { //this uses ChannelFactory to create the channel //you must specify the address, the binding and //the contract type (IMath) ChannelFactory<IMath> factory=new ChannelFactory<IMath>( new WSHttpBinding(), new EndpointAddress("http://localhost/MathService/Ep1")); IMath channel=factory.CreateChannel(); int result=channel.Add(35,7); factory.Close();

}

public class WCFClientApp{

public void SendMessageToEndpointUsingChannel() { //this uses ChannelFactory to create the channel //you must specify the address, the binding and //the contract type (IMath) ChannelFactory<IMath> factory=new ChannelFactory<IMath>( new WSHttpBinding(), new EndpointAddress("http://localhost/MathService/Ep1")); IMath channel=factory.CreateChannel(); int result=channel.Add(35,7); factory.Close();

}

Data transfer objects

• WCF support DTO’s• Use [DataContract]

decoration• All serializable objects

may be used instead -> less configurable

Plenum Discussion

• Use 5 minutes in your groups:• Differences with Web services / .NET Remoting

• Strength over Web services / .NET Remoting

• Weaknesses compared to –”-?

• Plenum: 5 minutes discussion of findings