1 Nordjyllands Erhvervakademi Windows Communication Foundation Introduction –.Net foundations –Communication Protocols –SOA tenets WCF –Basics –Contracts –Bindings Build a WCF application –Build the service –Build the client –Host the service

2 Nordjyllands Erhvervakademi NET At The Core

3 Nordjyllands Erhvervakademi Distributed applications Many protocols and api’s for communication Web services MSMQ COM+ DCOM.NET Remoting Sockets Corba P2P RMI

4 Nordjyllands Erhvervakademi WCF WCF provides a single extendable programming object model that can be used to interact with number of distributed technologies It makes it possible to offer multiple ways of communications, e.g. Web Services or.Net Remoting It is possible to extend the application with a new protocol without adding or refactoring code. It is done in the config file WCF is based on the design principles of SOA - Service-Oriented Architecture Supports strongly typed (.Net remoting) and loosely typed messages (XML) Supports multiple web service specs (WS*) e.g. Soap and Jason Fully integrated security models (both windows models and independent models)

5 Nordjyllands Erhvervakademi Service-Oriented Architecture Many definitions exists. The simple definition: SOA is a way to design distributed systems where several autonomous services works in conjunction by passing messages across boundaries using interfaces WCF is based on 4 tenets of SOA: 1.Boundaries are explicit 2.Services are autonomous 3.Services communicates via contract, not implementation 4.Service compatibility is based on policy

6 Nordjyllands Erhvervakademi The ABC of WCF Three things are needed to build a WCF application: A.Address The location of the service. Normally stored in the config file B.Binding How to bind to the service. Should it be xml, binary etc. C.Contract Normally implemented as an interface in c#. But it is possible to add [ServiceContract] attributes to a normal class. Note: You don’t have to do it in the order of A, B and C. Actually in most cases you do it the opposite order

7 Nordjyllands Erhvervakademi Contract Make an interface as usual. The interface methods will be the operations of the service. Use [ServiceContract] to define the interface as a (uhm..) service contract. Use [OperationContract] to define the method as an operation

8 Nordjyllands Erhvervakademi Binding The binding specifies how to use the service There may be specified more than one binding, meaning that there may be more than one way to access the service. The binding can specify: –The contracts implemented by the service –The transport layer (http, tcp, named pipes, msmq) –The channel for the transport (request-reply, one-way, duplex) –The encoding method (xml, binary, etc) –If a WS: Any supported web service protocols (WS-Transaction, WS-Security etc.)

9 Nordjyllands Erhvervakademi Http Binding The binding can be specified in the code by declaring an object, or (the easiest way) in the config file (using xml) Use http if the service should be reached by non.Net platforms or through Nat’s and firewalls There are by default 4 types of http binding: Element or the class BasicHttpBinding Basic web service functionality based on http and xml. Element, class WSHttpBinding Like BasicHttpBinding, but with support for transactions and reliable messaging Element, class WSDualHttpBinding Like WSHttpBinding, but makes possible for the service and the client to send message back and forth. Element, WSFederationHttpBinding Extended security. Supports ws-federation.

10 Nordjyllands Erhvervakademi Tcp binding Use tcp binding in-house on.Net based platforms Based on binary streams. Less bytes are transferred and no need for parsing Element, NetTcpBinding A secure and optimized method. Element, NetNamedPipeBinding Used for communication between applications on the same machine. Element, NetPeerTcpBinding Used for peer-to-peer, NetMsmqBinding Uses messages for cross-machine.Net platform communication, MsmqIntegrationBinding Used for communication with COM and native C++

11 Nordjyllands Erhvervakademi Which binding methods should I know for a start? BasicHttpBinding NetTcpBinding

12 Nordjyllands Erhvervakademi The EightBall example The steps 1.Define the contract ::= define the interface and add contract attributes 2.Implement the service class (that implements the interface) 3.Do the ABC in the App.config file (on the server) 4.Implement the server 5.Implement the client –Generate proxy –Use the service

13 Nordjyllands Erhvervakademi Step 1: Define the contract Just make an interface as usual, and add the attributes [ServiceContract(Namespace="noea.dk")] public interface IEightBall { [OperationContract] string ObtainAnswerToQuestion(string userQuestion); }

14 Nordjyllands Erhvervakademi Step 2: Implement the service Just a class public class MagicEightBallService:IEightBall { public MagicEightBallService() { Console.WriteLine("The 8-ball awaits your question...."); } public string ObtainAnswerToQuestion(string userQuestion) { string[] answers = { "Future uncertain", "Yes", "No", "Hazy", "Ask again later", "Definitely" }; Random r = new Random(); return string.Format("{0}? {1}",userQuestion,answers[r.Next(answers.Length)]); }

15 Nordjyllands Erhvervakademi Step 3: The config file (basic) <endpoint address="" binding="basicHttpBinding" contract="MagicEightBallServiceLib.IEightBall"/>

16 Nordjyllands Erhvervakademi Step 3: The config file (enable wsdl) ………… <service name="MagicEightBallServiceLib.MagicEightBallService" behaviorConfiguration="EightBallServiceMEXBehavior"> <endpoint address="" binding="basicHttpBinding" contract="MagicEightBallServiceLib.IEightBall"/> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> ………….. ……………….

17 Nordjyllands Erhvervakademi Step 4: The Server using System; using System.ServiceModel; using MagicEightBallServiceLib; namespace MagicEightBallServiceHost { class Program { static void Main(string[] args) { Console.WriteLine("Console Based WCF Host"); using (ServiceHost serviceHost = new ServiceHost(typeof(MagicEightBallService))) { serviceHost.Open(); Console.WriteLine("The service is ready."); Console.WriteLine("Press the Enter key to terminate service."); Console.ReadLine(); }

18 Nordjyllands Erhvervakademi The using statement (not the using declaration) The using statement ensures that the object is disposed, when it goes out of scope. Is similar to this code: { ServiceHost serviceHost = new ServiceHost(typeof(MagicEightBallService))) try { serviceHost.Open(); ….. } finally { if (serviceHost != null) ((IDisposable) serviceHost).Dispose(); }

19 Nordjyllands Erhvervakademi The Client Basically create the proxy class It can be done in VisualStudio by adding a Service Reference If you have the server and the client in the same solution, you have start the server from outside of VS before adding the reference Another way is to use svcutil.exe from the command prompt This will create a config file and a cs file containing the proxy class

20 Nordjyllands Erhvervakademi Step 5: The Client Autogenerated config file <binding name="BasicHttpBinding_IEightBall" closeTimeout="00:01:00" openTimeout="00:01:00" receiveTimeout="00:10:00" sendTimeout="00:01:00" allowCookies="false" bypassProxyOnLocal="false" hostNameComparisonMode="StrongWildcard" maxBufferSize="65536" maxBufferPoolSize="524288" maxReceivedMessageSize="65536" messageEncoding="Text" textEncoding="utf-8" transferMode="Buffered" useDefaultWebProxy="true"> <readerQuotas maxDepth="32" maxStringContentLength="8192" maxArrayLength="16384" maxBytesPerRead="4096" maxNameTableCharCount="16384" /> <transport clientCredentialType="None" proxyCredentialType="None" realm="" /> <endpoint address=" binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_IEightBall" contract="test.IEightBall" name="BasicHttpBinding_IEightBall" />

21 Nordjyllands Erhvervakademi Step 5: The Client Stripped config file <endpoint address=" binding="basicHttpBinding" contract="test.IEightBall" name="BasicHttpBinding_IEightBall" />

22 Nordjyllands Erhvervakademi Step 5: The Client The exe file using MagicEightBallClient.test; namespace MagicEightBallClient { class Program { static void Main(string[] args) { using (test.EightBallClient ball = new EightBallClient()) { Console.Write("Your question: "); string question = Console.ReadLine(); string answer = ball.ObtainAnswerToQuestion(question); Console.WriteLine("8-ball says: {0}",answer); } Console.ReadLine(); }

23 Nordjyllands Erhvervakademi Run the example The server must run in administrator mode on Vista and Windows 7 Either start Visual Studio or the server in administrator mode: right click-> run as administrator

24 Nordjyllands Erhvervakademi Exercise Change the EightBall server so it also supports.netTcp Change the client to use the.netTcp Change the RemoteBank to WCF. Use the WCF Service Library template, and test it by using WcfTestClient.exe see Troelsen p. 901 If you are fast: Make it possible to run RemoteBank as a service see Troelsen p >