WCF進(jìn)階:為每個(gè)操作附加身份信息

上文WCF進(jìn)階：將消息正文Base64編碼中介紹了實(shí)現(xiàn)自定義MessageInspector來記錄消息和實(shí)現(xiàn)自定義Formatter來改寫消息，本文介紹一下在WCF中使用SoapHeader進(jìn)行驗(yàn)證的兩種實(shí)現(xiàn)方法，同時(shí)再次復(fù)習(xí)自定義Inspector和自定義EndpointBehavior。

上文WCF進(jìn)階：將消息正文Base64編碼中介紹了實(shí)現(xiàn)自定義MessageInspector來記錄消息和實(shí)現(xiàn)自定義Formatter來改寫消息，本文介紹一下在WCF中使用SoapHeader進(jìn)行驗(yàn)證的兩種實(shí)現(xiàn)方法，同時(shí)再次復(fù)習(xí)自定義Inspector和自定義EndpointBehavior。

在Xml Web Service中能將用戶的身份信息如用戶名，密碼添加到SoapHeader中，從而實(shí)現(xiàn)服務(wù)調(diào)用的身份驗(yàn)證，這種做法是沿用了Http中用戶名，密碼身份驗(yàn)證，是我們最樂于接受的。而在WCF中因?yàn)樘峁┝朔浅＝训陌踩珯C(jī)制，但實(shí)現(xiàn)起來真是不夠簡單。對于多數(shù)應(yīng)用情景來講，有點(diǎn)大炮打蚊子的感覺。因此好多人在網(wǎng)上詢問在WCF中如何象XMl Web Service一樣使用SoapHeader來完成用戶名，密碼身份驗(yàn)證。傳統(tǒng)的辦法是通過在服務(wù)的操作中從OperationContext.Current.IncomingMessageHeaders來獲取Header中的內(nèi)容，而在客戶端在OperationContext.Current.OutgoingMessageHeaders中添加MessageHeader。下面的代碼片段簡要的介紹了這種實(shí)現(xiàn)：

在服務(wù)端的一個(gè)Operation中

public string GetData(int value)

{

System.Text.Encoding encoding = System.Text.Encoding.GetEncoding("utf-8");

string username = "";

string pwd = "";

int index = OperationContext.Current.IncomingMessageHeaders.FindHeader("username", "http://tempuri.org");

if (index >= 0)

{

username = OperationContext.Current.IncomingMessageHeaders.GetHeader<string>(index).ToString();

}

index = OperationContext.Current.IncomingMessageHeaders.FindHeader("pwd", "http://tempuri.org");

if (index >= 0)

{

pwd = OperationContext.Current.IncomingMessageHeaders.GetHeader<string>(index).ToString();

}

return string.Format("You entered: {0}", value);

}

在客戶端調(diào)代碼如下：

Robin_Wcf_Formatter_Svc.Service1Client svc = new Robin_Wcf_Formatter_Svc.Service1Client();

using (OperationContextScope scope = new OperationContextScope(svc.InnerChannel))

{

MessageHeader header = MessageHeader.CreateHeader("username", "http://tempuri.org", "robinzhang");

OperationContext.Current.OutgoingMessageHeaders.Add(header);

header = MessageHeader.CreateHeader("pwd", "http://tempuri.org", "robinzhang");

OperationContext.Current.OutgoingMessageHeaders.Add(header);

string res = svc.GetData(10);

}

通過上邊的代碼實(shí)現(xiàn)，已經(jīng)能在WCF中使用SoapHeader來傳遞身份信息了。但這種方式需要在每次客戶端調(diào)用和每個(gè)服務(wù)操作中都增加類似代碼片斷。比較麻煩。多數(shù)情況下，我們的服務(wù)開發(fā)好之后，往往只開放給固定的用戶用于消費(fèi)，如果我們的服務(wù)的實(shí)例模式為PerCall，也就是不保存會話，同時(shí)我們又希望能驗(yàn)證調(diào)用者的身份信息，我們需要在每個(gè)Operation的消息中增加SoapHeader來附加身份信息。這樣服務(wù)即可保證每一個(gè)操作都不被非法調(diào)用。閱讀完上篇文章，已經(jīng)了解到通過MessageInspector能攔截消息用于記錄或者修改，如果在攔截到消息之后，在消息中增加MessageHeader便可以實(shí)現(xiàn)上述需求。為此我們實(shí)現(xiàn)了一個(gè)實(shí)現(xiàn)IClientMessageInspector, IDispatchMessageInspector, IEndpointBehavior三個(gè)接口的類，這樣該類就承擔(dān)了兩種角色，自定義MessageInspector,自定義EndpointBehavior。這個(gè)類的代碼如下：

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ServiceModel.Dispatcher;

using System.ServiceModel.Description;

using System.ServiceModel.Channels;

using System.ServiceModel;

namespace RobinLib

{

public class AttachUserNamePasswordBehavior : IClientMessageInspector, IDispatchMessageInspector, IEndpointBehavior

{

private static string UserName = System.Configuration.ConfigurationSettings.AppSettings["username"];

private static string Password = System.Configuration.ConfigurationSettings.AppSettings["pwd"];

public AttachUserNamePasswordBehavior()

{

}

#region IClientMessageInspector 成員

public void AfterReceiveReply(ref System.ServiceModel.Channels.Message reply, object correlationState)

{

}

public object BeforeSendRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel)

{

MessageHeader userNameHeader = MessageHeader.CreateHeader("OperationUserName", "http://tempuri.org", UserName, false, "");

MessageHeader pwdNameHeader = MessageHeader.CreateHeader("OperationPwd", "http://tempuri.org", Password, false, "");

request.Headers.Add(userNameHeader);

request.Headers.Add(pwdNameHeader);

Console.WriteLine(request);

return null;

}

#endregion

#region IDispatchMessageInspector 成員

string GetHeaderValue(string key)

{

int index = OperationContext.Current.IncomingMessageHeaders.FindHeader(key, "http://tempuri.org");

if (index >= 0)

{

return OperationContext.Current.IncomingMessageHeaders.GetHeader<string>(index).ToString();

}

return null;

}

public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel, System.ServiceModel.InstanceContext instanceContext)

{

Console.WriteLine(request);

string username = GetHeaderValue("OperationUserName");

string pwd = GetHeaderValue("OperationPwd");

if (username == "robinzhang" && pwd == "111111")

{

}

else

{

throw new Exception("操作中的用戶名，密碼不正確！");

}

return null;

}

public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)

{

}

#endregion

#region IEndpointBehavior 成員

public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)

{

}

public void ApplyClientBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.ClientRuntime clientRuntime)

{

clientRuntime.MessageInspectors.Add(new AttachUserNamePasswordBehavior());

}

public void ApplyDispatchBehavior(ServiceEndpoint endpoint, System.ServiceModel.Dispatcher.EndpointDispatcher endpointDispatcher)

{

endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new AttachUserNamePasswordBehavior());

}

public void Validate(ServiceEndpoint endpoint)

{

}

#endregion

}

象上文一樣，將自定義的EndpointBehavior通過代碼方式應(yīng)用到Host和Proxy中

服務(wù)宿主程序

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.ServiceModel;

namespace Robin_Wcf_OperationWithToken_Host

{

public class Program

{

static void Main(string[] args)

{

//服務(wù)地址

Uri baseAddress = new Uri("net.tcp://127.0.0.1:8081/Robin_Wcf_Formatter");

ServiceHost host = new ServiceHost(typeof(Robin_Wcf_OperationWithToken_SvcLib.Service1), new Uri[] { baseAddress });

//服務(wù)綁定

NetTcpBinding bind = new NetTcpBinding();

host.AddServiceEndpoint(typeof(Robin_Wcf_OperationWithToken_SvcLib.IService1), bind, "");

if (host.Description.Behaviors.Find<System.ServiceModel.Description.ServiceMetadataBehavior>() == null)

{

System.ServiceModel.Description.ServiceMetadataBehavior svcMetaBehavior = new System.ServiceModel.Description.ServiceMetadataBehavior();

svcMetaBehavior.HttpGetEnabled = true;

svcMetaBehavior.HttpGetUrl = new Uri("http://127.0.0.1:8001/Mex");

host.Description.Behaviors.Add(svcMetaBehavior);

}

host.Opened += new EventHandler(delegate(object obj, EventArgs e)

{

Console.WriteLine("服務(wù)已經(jīng)啟動！");

});

foreach (var sep in host.Description.Endpoints)

{

sep.Behaviors.Add(new RobinLib.AttachUserNamePasswordBehavior());

}

host.Open();

Console.Read();

}

客戶端代理

[System.Diagnostics.DebuggerStepThroughAttribute()]

[System.CodeDom.Compiler.GeneratedCodeAttribute("System.ServiceModel", "3.0.0.0")]

public partial class Service1Client : System.ServiceModel.ClientBase<Robin_Wcf_OperationWithToken_ClientApp.ServiceReference1.IService1>, Robin_Wcf_OperationWithToken_ClientApp.ServiceReference1.IService1

{

public Service1Client()

{