要對SOAP消息進行攔截和修改,我們需要實現兩個接口,它們都位於System.ServiceModel.Dispatcher (程序集System.ServiceModel)。下面分別價紹。
接口一:IClientMessageInspector
從名字中我們可以猜測,它是用來攔截客戶消息的,而看看它的方法,你就更加肯定當初的猜測了。
- BeforeSendRequest:向服務器發送請求前攔截或修改消息(事前控制)
- AfterReceiveReply:接收到服務器的回覆消息後,在調用返回之前攔截或修改消息(事後諸葛亮)
接口二:IDispatchMessageInspector
剛纔那個接口是針對客戶端的,而這個是針對服務器端的。
- AfterReceiveRequest:接收客戶端請求後,在進入操作處理代碼之前攔截或修改消息(欺上)
- BeforeSendReply:服務器向客戶端發送回覆消息之前攔截和修改消息(瞞下)。
雖然實現了這兩個接口,但你會有新的疑問,怎麼用?把它們放到哪兒才能攔截消息?因此,下一步就是要實現IEndpointBehavior按口(System.ServiceModel.Description命名空間,程序集System.ServiceModel),它有四個方法,而我們只需要處理兩個就夠了。
下面是MSDN的翻譯版本說明:
使用 ApplyClientBehavior 方法可以在客戶端應用程序中修改、檢查或插入對終結點中的擴展。
使用 ApplyDispatchBehavior 方法可以在服務應用程序中修改、檢查或插入對終結點範圍執行的擴展。
我想不用額外解釋了,說白了就是一個在客戶攔截和修改消息,另一個在服務器端攔截和修改消息。
在實現這兩個方法時,和前面我們實現的IClientMessageInspector和IDispatchMessageInspector聯繫起來就OK了。
做完了IEndpointBehavior的事情後,把它插入到服務終結點中就行了,無論是服務器端還是客戶端,這一步都必須的,因爲我們實現的攔截器是包括兩個端的,因此,較好的做法是把這些類寫到一個獨立的類庫(dll)中,這樣一來,服務器端和客戶端都可以引用它。
示例代碼
1、實現消息攔截器
using System;
using System.ServiceModel.Dispatcher;
using System.ServiceModel.Description;
namespace MyMessageIntercept
{
/// <summary>
/// 消息攔截器【實現客戶端和服務端的消息攔截】
/// </summary>
public class MessageIntercept:IClientMessageInspector,IDispatchMessageInspector
{
public void AfterReceiveReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
Console.WriteLine("客戶端接收到的回覆:{0}\n", reply);
}
public object BeforeSendRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel)
{
Console.WriteLine("客戶端發送請求前的SOAP消息:{0}\n", request);
return null;
}
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel, System.ServiceModel.InstanceContext instanceContext)
{
Console.WriteLine("服務器端接收到的請求:{0}\n", request);
return null;
}
public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
Console.WriteLine("服務器將作出以下回復:{0}\n", reply);
}
}
/// <summary>
/// 將自定義的消息攔截器(MessageIntercept)插入到終結點行爲
/// </summary>
public class MyEndPointBehavior : IEndpointBehavior
{
public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
{
//不需要
}
public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
//植入"竊聽器"客戶端
clientRuntime.ClientMessageInspectors.Add(new MessageIntercept());
}
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
//植入"竊聽器"服務端
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new MessageIntercept());
}
public void Validate(ServiceEndpoint endpoint)
{
//不需要
}
}
}
2、實現服務端
using System;
using System.ServiceModel;
using System.ServiceModel.Description;
using System.Runtime.Serialization;
using MyMessageIntercept;
namespace Server
{
class Program
{
//設置服務並啓動
static void Main()
{
//服務基地址
Uri baseUri = new Uri("http://localhost:3000/Service");
//聲明服務器主機
using (ServiceHost host = new ServiceHost(typeof(MyService), baseUri))
{
//添加綁定和終結點
WSHttpBinding binding = new WSHttpBinding();
host.AddServiceEndpoint(typeof(IService), binding, "test");
//添加服務描述
host.Description.Behaviors.Add(new ServiceMetadataBehavior { HttpGetEnabled = true });
//把自定義的"MyEndPointBehavior"插入到終結點中
foreach (var endPoint in host.Description.Endpoints)
{
endPoint.EndpointBehaviors.Add(new MyEndPointBehavior());
}
//啓動服務
try
{
host.Open();
Console.WriteLine("服務已啓動");
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Console.ReadKey();
//關閉服務
host.Close();
}
}
}
/// <summary>
/// 定義服務協定
/// </summary>
[ServiceContract]
public interface IService
{
[OperationContract]
int AddInt(int a, int b);
[OperationContract]
Student GetStudent();
[OperationContract]
CalculateResultResponse CaculateNumber(CalculateRequest request);
}
/// <summary>
/// 實現服務協定
/// </summary>
public class MyService : IService
{
public int AddInt(int a, int b)
{
return a + b;
}
public Student GetStudent()
{
Student st = new Student
{
Name = "小明",
Age = 23
};
return st;
}
public CalculateResultResponse CaculateNumber(CalculateRequest request)
{
CalculateResultResponse result = new CalculateResultResponse();
switch (request.Operation)
{
case "+":
result.CalculateResult = request.NumberA + request.NumberB;
break;
case "-":
result.CalculateResult = request.NumberA - request.NumberB;
break;
case "*":
result.CalculateResult = request.NumberA * request.NumberB;
break;
case "/":
result.CalculateResult = request.NumberA / request.NumberB;
break;
default:
throw new ArgumentException("運算操作符只允許'+'、'-'、'*'、'/'.");
}
return result;
}
}
[DataContract]
public class Student
{
[DataMember]
public string Name { get; set; }
[DataMember]
public int Age { get; set; }
}
[MessageContract]
public class CalculateRequest
{
/// <summary>
/// 操作符
/// </summary>
[MessageHeader]
public string Operation { get; set; }
/// <summary>
/// 第一個數
/// </summary>
[MessageBodyMember]
public int NumberA { get; set; }
/// <summary>
/// 第二個數
/// </summary>
[MessageBodyMember ]
public int NumberB { get; set; }
}
/// <summary>
/// 計算返回的結果
/// </summary>
[MessageContract]
public class CalculateResultResponse
{
/// <summary>
/// 計算結果
/// </summary>
[MessageBodyMember]
public int CalculateResult { get; set; }
}
}
3、實現客戶端
using System;
using MyMessageIntercept;
namespace Client
{
class Program
{
private static void Main()
{
WS.ServiceClient sc = new WS.ServiceClient();
//記得在客戶端也要插入自定義的"MyEndPointBehavior"
sc.Endpoint.EndpointBehaviors.Add(new MyEndPointBehavior());
try
{
// 1、調用帶元數據參數和返回值的操作
Console.WriteLine("10和55相加的結果是:{0}\n", sc.AddInt(10, 55));
//2、調用帶有數據協定的操作
WS.Student st = sc.GetStudent();
Console.WriteLine("-----學生信息--------\n姓名:{0}\n年齡:{1}\n", st.Name, st.Age);
//3、調用帶有消息協定的操作
Console.WriteLine("12乘以56的結果是:{0}\n", sc.CaculateNumber("*", 12, 56));
sc.Close();
}
catch (Exception ex)
{
Console.WriteLine(ex.Message);
}
Console.ReadKey();
}
}
}
消息攔截效果圖
修改消息,只需要對消息攔截器(MessageIntercept)類做修改
using System;
using System.ServiceModel.Dispatcher;
using System.ServiceModel.Description;
namespace MyMessageIntercept
{
/// <summary>
/// 消息攔截器【實現客戶端和服務端的消息攔截】
/// </summary>
public class MessageIntercept:IClientMessageInspector,IDispatchMessageInspector
{
public void AfterReceiveReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
//Console.WriteLine("客戶端接收到的回覆:\n{0}", reply);
}
public object BeforeSendRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel)
{
//Console.WriteLine("客戶端發送請求前的SOAP消息:\n{0}", request);
// (客服端)插入驗證信息
System.ServiceModel.Channels.MessageHeader hdUserName = System.ServiceModel.Channels.MessageHeader.CreateHeader("user", "myTest", "admin");
System.ServiceModel.Channels.MessageHeader hdPassWord = System.ServiceModel.Channels.MessageHeader.CreateHeader("pw", "myTest", "123");
request.Headers.Add(hdUserName);
request.Headers.Add(hdPassWord);
return null;
}
public object AfterReceiveRequest(ref System.ServiceModel.Channels.Message request, System.ServiceModel.IClientChannel channel, System.ServiceModel.InstanceContext instanceContext)
{
//Console.WriteLine("服務器端:接收到的請求:\n{0}", request);
// (服務端)栓查驗證信息
string un = request.Headers.GetHeader<string>("user", "myTest");
string ps = request.Headers.GetHeader<string>("pw", "myTest");
if (un == "admin" && ps == "123")
{
Console.WriteLine("用戶名和密碼正確.");
}
else
{
throw new Exception("驗證失敗!");
}
return null;
}
public void BeforeSendReply(ref System.ServiceModel.Channels.Message reply, object correlationState)
{
//Console.WriteLine("服務器即將作出以下回復:\n{0}", reply);
}
}
/// <summary>
/// 將自定義的消息攔截器(MessageIntercept)插入到終結點行爲
/// </summary>
public class MyEndPointBehavior : IEndpointBehavior
{
public void AddBindingParameters(ServiceEndpoint endpoint, System.ServiceModel.Channels.BindingParameterCollection bindingParameters)
{
//不需要
}
public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
{
//植入"竊聽器"客戶端
clientRuntime.ClientMessageInspectors.Add(new MessageIntercept());
}
public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
{
//植入"竊聽器"服務端
endpointDispatcher.DispatchRuntime.MessageInspectors.Add(new MessageIntercept());
}
public void Validate(ServiceEndpoint endpoint)
{
//不需要
}
}
}
注意:添加對System.Runtime.Serialization的引用。前面我們說過,如果安裝證書進行身份驗證會相當麻煩,而可以通過修改SOAP消息頭來驗證,但是,上次的做法會有一個麻煩,那就是每次調用操作協定都要手動修改一次,這一次,我們直接在終結點級別進行修改和驗證,就省去了許多功夫。