我的WCF之旅(2)Endpoint Overview

我的W CF之旅（2）：Endpoint OverviewWCF实际上是构建了一个框架，这个框架实现了在互联系统中各个Application之间如何通信。

使得Developers和Architect在构建分布式系统中，无需在考虑如何去实现通信相关的问题，更加关注与系统的业务逻辑本身。

而在WCF Infrastructure中，各个Application之间的通信是由Endpoint来实现的。

Endpoint的结构Endpoint包含以下4个对象：∙Address: Address通过一个URI唯一地标识一个Endpoint，并告诉潜在的WCF service的调用者如何找到这个Endpoint。

所以Address解决了Where to locate the WCF Service？∙Binding: Binding实现在Client和Service通信的所有底层细节。

比如Client与Service之间传递的Message是如何编码的——text/XML, binary，MTOM；这种Message的传递是采用的哪种Transport——TCP, Http, Nam ed Pipe, MSMQ; 以及采用怎样的机制解决Secu re Messaging的问题——SSL，Message Level Security。

所以Binding解决的是How t o communicate with service？∙Contract: Contract的主要的作用是暴露某个WCF Service所提供的所有有效的Functiona lity。

从Message Exchange的层面上讲，Contract实际上是抱每个Operation转化成为相对应的Message Exchange Pattern——MEP（Request/Response；One-way；Duple x）。

所以Contract解决的是What functionalities do the Service provide？∙ Behavior: Behavior的主要作用是定制Endpoint在运行时的一些必要的Behavior。

比如S ervice 回调Client的Timeout；Client采用的Credential type；以及是否支持Transactio n等。

当我们Host一个WCF Service的时候，我们必须给他定义一个或多个Endpoint，然后ser vice通过这个定义的Endpoint进行监听来自Client端的请求。

当我们的Application需要调用这个Service的时候，因为Client 和Service是通过Endpoint的进行通信的，所以我们必须为我们的Application定义Client端的Endpoint。

只有当Client的Endpoint和Servi ce端某个Endpoint相互匹配（Service端可以为一个Service定义多个Endpoint），Clien t端的请求才能被Service端监听到。

也就是说，我们只有在Client具有一个与Service端完全匹配的Endpoint，我们才能调用这个Service。

而这种匹配是比较严格的，比如从匹配Add ress方面，Client端和Service端的Endpoint Address不仅仅在URI上要完全匹配Servi ce，他们的Headers也需要相互匹配。

对于Binding, 一般地，Client需要有一个与Servic e端完全一样的Binding，他们之间才能通信。

Sample首先给一个Sample，以便我们对在WCF Service Aplication中如何定义Endpoint有一个感性的认识。

整个Solution的结构参照下图，我的上一篇Blog([原创]我的WCF之旅（1）：创建一个简单的WCF程序)中有详细的介绍。

你也可以通过后面的Link下载相应的Source Code（/files/artech/Artec h.WCFService.zip ）1． Service Contract：Artech..WC fService.Contract/ServiceContract/IGen eralCalculator.csusing System;using System.Collections.Generic;using System.Text;using System.ServiceModel;nam espace Artech.WCFService.Contract{[ServiceContract]public interface IGeneralCalculator{[OperationContract]double Add(double x, double y);}}2. Service: Artech.WCFSerice.Service/GeneralCalculatorService.csusing System;using System.Collections.Generic;using System.Text;using Artech.WCFService.Contract;nam espace Artech.WCFService.Service{public class GeneralCalculatorService:IGeneralCalculator{IGeneralCalculator Members}}3. Hosting: Artech.WCFService.Hosting/Program.csusing System;using System.Collections.Generic;using System.Text;using System.ServiceModel;using Artech.WCFService.Contract;using Artech.WCFService.Service;using System.ServiceModel.Description;nam espace Artech.WCFService.Hosting{class Program{static void Main(string[] args){//HostCalculatorServiceViaCode();HostCalculatorSerivceViaConfiguration();}///<summary>/// Hosting a service using managed code without any configuraiton infor mation./// Please note that the related configuration data should be removed befo re calling the m ethod.///</summary>static void HostCalculatorServiceViaCode(){Uri httpBaseAddress =new Uri("http://localhost:8888/generalCalculato r");Uri tcpBaseAddress =new Uri("net.tcp://localhost:9999/generalCalculator");using (ServiceHost calculatorSerivceHost =new ServiceHost(typeof(Ge neralCalculatorService), httpBaseAddress, tcpBaseAddress)){BasicHttpBinding httpBinding =new BasicHttpBinding();NetTcpBinding tcpBinding =new NetTcpBinding();calculatorSerivceHost.AddServiceEndpoint(typeof(IGeneralCalculato r), httpBinding, string.Empty);calculatorSerivceHost.AddServiceEndpoint(typeof(IGeneralCalculato r), tcpBinding, string.Empty);ServiceMetadataBehavior behavior = calculatorSerivceHost.Descripti on.Behaviors.Find<ServiceMetadataBehavior>();{if(behavior ==null){behavior =new ServiceMetadataBehavior();behavior.HttpGetEnabled =true;calculatorSerivceHost.Description.Behaviors.Add(behavior);}else{behavior.HttpGetEnabled =true;}}calculatorSerivceHost.Opened += delegate{Console.WriteLine("Calculator Service has begun to listen "); };calculatorSerivceHost.Open();Console.Read();}}static void HostCalculatorSerivceViaConfiguration(){using (ServiceHost calculatorSerivceHost =new ServiceHost(typeof(Ge neralCalculatorService))){calculatorSerivceHost.Opened += delegate{Console.WriteLine("Calculator Service has begun to listen "); };calculatorSerivceHost.Open();Console.Read();}}}}4. Service.svc: http://localhost/WCFService/ GeneralCalculatorService. svc<%@ ServiceHost Language="C#" Debug="t rue" Service="Artech.WCFService. Service.GeneralCalculatorService" %>5. Client: Artech.WCFService.Client/ GeneralCalculatorClient.cs & Progr am.csusing System;using System.Collections.Generic;using System.Text;using System.ServiceModel;using System.ServiceModel.Channels;using Artech.WCFService.Contract;nam espace Artech.WCFService.Client{class GeneralCalculatorClient:Client Base<IGeneralCalculator>,IGeneralCalcul ator{public GeneralCalculatorClient(): base(){ }public GeneralCalculatorClient(string endpointConfigurationName): base(endpointConfigurationName){ }public GeneralCalculatorClient(Binding binding, EndpointAddress address): base(binding, address){ }IGeneralCalculator Members}}using System;using System.Collections.Generic;using System.Text;using System.ServiceModel;using System.ServiceModel.Channels;using Artech.WCFService.Contract;nam espace Artech.WCFService.Client{class Program{static void Main(){try{//InvocateCalclatorServiceViaCode();InvocateCalclatorServiceViaConfiguration(); }catch (Exception ex){Console.WriteLine(ex.Message);}Console.Read();}static void InvocateCalclatorServiceViaCode(){Binding httpBinding =new BasicHttpBinding();Binding tcpBinding = new NetTcpBinding();EndpointAddress httpAddress =new EndpointAddress("http://localhost: 8888/generalCalculator");EndpointAddress tcpAddress =new EndpointAddress("net.tcp://localhos t:9999/generalCalculator");EndpointAddress httpAddress_iisHost =new EndpointAddress("http://lo calhost/wcfservice/GeneralCalculatorService.svc");Console.WriteLine("Invocate self-host calculator service ");Invocate Self-host serviceConsole.WriteLine("\n\nInvocate IIS-host cal culator service ");Invocate IIS-host service}static void InvocateCalclatorServiceViaConfiguration(){Console.WriteLine("Invocate self-host calculator service ");Invocate Self-host serviceConsole.WriteLine("\n\nInvocate IIS-host cal culator service ");Invocate IIS-host service}}}<?xml version="1.0" encoding="utf-8" ?><configuration><system.serviceModel><behaviors><serviceBehaviors><behavior name="calculatorServieBehavior"><serviceMetadata httpGetEnabled="true"/></behavior></serviceBehaviors></behaviors><services><service behaviorConfiguration="calculatorServieBehavior" name="Art ech.WCFService.Service.GeneralCalculatorService"><endpoint address="" binding="basicHttpBinding" contract="Artech. WCFService.Contract.IGeneralCalculator"></endpoint><endpoint address="" binding="netTcpBinding" contract="Artech.W CFService.Contract.IGeneralCalculator"/><host><baseAddresses><add baseAddress="http://localhost:8888/generalcalculator"/><add baseAddress="net.tcp://localhost:9999/generalCalculator "/></baseAddresses></host></service></services></system.serviceModel></configuration>7. IIS-Host Configuration:<?xml version="1.0"?><configuration xmlns="http://schem /.NetConfiguration/v2.0"> <system.serviceModel><behaviors><serviceBehaviors><behavior name="calculatorServiceBehavior"><serviceMetadata httpGetEnabled ="true"></serviceMetadata></behavior></serviceBehaviors></behaviors><services><service nam e="Artech.WCFService.Service.GeneralCalculatorService" beh aviorConfiguration="calculatorServiceBehavior"><endpoint binding="basicHttpBinding" contract="Artech.WCFService.Contr act.IGeneralCalculator"></endpoint></service></services></system.serviceModel><system.web><compilation debug="t rue"><assemblies><add assem bly="System.Security, Version=2.0.0.0, Culture=neutra l, Public KeyToken=B03F5F7F11D50A3A"/><add assem bly="Microsoft.Transactions.Bridge, Version=3.0.0.0, Cul ture=neutral, Public KeyToken=B03F5F7F11D50A3A"/><add assem bly="SMDiagnostics, Version=3.0.0.0, Culture=neutra l, Public KeyToken=B77A5C561934E089"/><add assem bly="System.IdentityModel.Selectors, Version=3.0.0. 0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/><add assem bly="System.DirectoryServices, Version=2.0.0.0, Cultur e=neutral, PublicKeyToken=B03F5F7F11D50A3A"/><add assem bly="System.Web.RegularExpressions, Version=2.0.0. 0, Culture=neutral, PublicKeyToken=B03F5F7F11D50A3A"/><add assem bly="System.Transactions, Version=2.0.0.0, Culture=ne utral, PublicKeyToken=B77A5C561934E089"/><add assem bly="System.Messaging, Version=2.0.0.0, Culture=neut ral, PublicKeyToken=B03F5F7F11D50A3A"/><add assem bly="System.ServiceProcess, Version=2.0.0.0, Culture= neutral, PublicKeyToken=B03F5F7F11D50A3A"/></assemblies></com pilation> </system.web></configuration>8. Client configuration: Artech.WCFService.Client/App.config<?xml version="1.0" encoding="utf-8" ?><configuration><system.serviceModel><client><endpoint address="http://localhost:8888/generalCalculator" binding="basic HttpBinding" contract="Artech.WCFService.Contract.IGeneralCalculator" name="s elfHostEndpoint_http"/><endpoint address="net.tcp://localhost:9999/generalCalculator" binding=" netTcpBinding" contract="Artech.WCFService.Contract.IGeneralCalculator" name ="selfHostEndpoint_tcp"/><endpoint address="http://localhost/wcfservice/GeneralCalculatorService.s vc" binding="basicHttpBinding" contract="Artech.WCFService.Contract.IGeneralC alculator" name="iisHostEndpoint"/></client></system.serviceModel></configuration>如何在Application中定义Endpoint对于Self-Host的Service，绝大部分的Endpoint相关的信息都具有两种定义方式——Mana ged Code 和Configuration。