12

我正在尝试在 WCF 服务实现中使用IDispatchMessageInspector来访问自定义标头值。

就像是：

public class MyService : IMyService
{
    public List<string> GetNames()
    {
        var headerInspector = new CustomHeaderInspector();

        // Where do request & client channel come from?
        var values = headerInspector.AfterReceiveRequest(ref request, clientChannel, OperationContext.Current.InstanceContext);            
    }
}

我已经实现了自己的 IDispatchMessageInspector 类。

public class CustomHeaderInspector : IDispatchMessageInspector
{
    public object AfterReceiveRequest(ref Message request, IClientChannel channel, InstanceContext instanceContext)
    {
        var prop = (HttpRequestMessageProperty)request.Properties[HttpRequestMessageProperty.Name];
        var userName = prop.Headers["Username"];

        return userName;
    }
}

我如何通过

  • System.ServiceModel.Channels。留言和

  • 系统.服务模型。客户端频道

从服务实现调用AfterReceiveRequest ？

编辑：

许多文章都喜欢this one or this one，举例说明如何实现你自己的ServiceBehavior。所以你的服务实现看起来像这样：

[MyCustomBehavior]
public class MyService : IMyService
{
    public List<string> GetNames()
    {
        // Can you use 'MyCustomBehavior' here to access the header properties?
    }
}

那么有了这个，我可以MyCustomBehavior在服务操作方法中以某种方式访问​​来访问自定义标头值吗？

4

5 回答 5

7

您必须配置

<extensions>
  <behaviorExtensions>
    <add 
      name="serviceInterceptors" 
      type="CustomHeaderInspector , MyDLL, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null"
    />
  </behaviorExtensions>
</extensions>

然后扩展将在您的 WCF 堆栈中处理。服务本身没有概念，serviceInterceptors您不必在第一个代码块中执行类似的操作。WCF 堆栈将为您注入 Inspector。

MSDN：system.servicemodel.dispatcher.idispatchmessageinspector

于 2014-06-16T13:59:02.633 回答
5

我将 IClientMessageInspector 用于相同的目标。以下是如何从代码中应用它们：

 var serviceClient = new ServiceClientClass(binding, endpointAddress);
serviceClient.Endpoint.Behaviors.Add(
            new MessageInspectorEndpointBehavior<YourMessageInspectorType>());


/// <summary>
/// Represents a run-time behavior extension for a client endpoint.
/// </summary>
public class MessageInspectorEndpointBehavior<T> : IEndpointBehavior
    where T: IClientMessageInspector, new()
{
    /// <summary>
    /// Implements a modification or extension of the client across an endpoint.
    /// </summary>
    /// <param name="endpoint">The endpoint that is to be customized.</param>
    /// <param name="clientRuntime">The client runtime to be customized.</param>
    public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime)
    {
        clientRuntime.MessageInspectors.Add(new T());
    }

    /// <summary>
    /// Implement to pass data at runtime to bindings to support custom behavior.
    /// </summary>
    /// <param name="endpoint">The endpoint to modify.</param>
    /// <param name="bindingParameters">The objects that binding elements require to support the behavior.</param>
    public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters)
    {
        // Nothing special here
    }

    /// <summary>
    /// Implements a modification or extension of the service across an endpoint.
    /// </summary>
    /// <param name="endpoint">The endpoint that exposes the contract.</param>
    /// <param name="endpointDispatcher">The endpoint dispatcher to be modified or extended.</param>
    public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher)
    {
        // Nothing special here
    }

    /// <summary>
    /// Implement to confirm that the endpoint meets some intended criteria.
    /// </summary>
    /// <param name="endpoint">The endpoint to validate.</param>
    public void Validate(ServiceEndpoint endpoint)
    {
        // Nothing special here
    }
}

这是我用来将客户端版本传递给服务器并在自定义标头中检索服务器版本的 MessageInspector 的示例实现：

/// <summary>
/// Represents a message inspector object that can be added to the <c>MessageInspectors</c> collection to view or modify messages.
/// </summary>
public class VersionCheckMessageInspector : IClientMessageInspector
{
    /// <summary>
    /// Enables inspection or modification of a message before a request message is sent to a service.
    /// </summary>
    /// <param name="request">The message to be sent to the service.</param>
    /// <param name="channel">The WCF client object channel.</param>
    /// <returns>
    /// The object that is returned as the <paramref name="correlationState " /> argument of
    /// the <see cref="M:System.ServiceModel.Dispatcher.IClientMessageInspector.AfterReceiveReply(System.ServiceModel.Channels.Message@,System.Object)" /> method.
    /// This is null if no correlation state is used.The best practice is to make this a <see cref="T:System.Guid" /> to ensure that no two
    /// <paramref name="correlationState" /> objects are the same.
    /// </returns>
    public object BeforeSendRequest(ref Message request, IClientChannel channel)
    {
        request.Headers.Add(new VersionMessageHeader());
        return null;
    }

    /// <summary>
    /// Enables inspection or modification of a message after a reply message is received but prior to passing it back to the client application.
    /// </summary>
    /// <param name="reply">The message to be transformed into types and handed back to the client application.</param>
    /// <param name="correlationState">Correlation state data.</param>
    public void AfterReceiveReply(ref Message reply, object correlationState)
    {
        var serverVersion = string.Empty;
        var idx = reply.Headers.FindHeader(VersionMessageHeader.HeaderName, VersionMessageHeader.HeaderNamespace);
        if (idx >= 0)
        {
            var versionReader = reply.Headers.GetReaderAtHeader(idx);
            while (versionReader.Name != "ServerVersion"
                   && versionReader.Read())
            {
                serverVersion = versionReader.ReadInnerXml();
                break;
            }
        }

        ValidateServerVersion(serverVersion);
    }

    private static void ValidateServerVersion(string serverVersion)
    {
        // TODO...
    }
}

public class VersionMessageHeader : MessageHeader
{
    public const string HeaderName = "VersionSoapHeader";
    public const string HeaderNamespace = "<your namespace>";
    private const string VersionElementName = "ClientVersion";

    public override string Name
    {
        get { return HeaderName; }
    }

    public override string Namespace
    {
        get { return HeaderNamespace; }
    }

    protected override void OnWriteHeaderContents(XmlDictionaryWriter writer, MessageVersion messageVersion)
    {
        writer.WriteElementString(
            VersionElementName,
            Assembly.GetExecutingAssembly().GetName().Version.ToString());
    }
}
于 2014-06-17T12:42:12.657 回答
1

我做了什么来访问我在里面设置的详细信息IDispatchMessageInspector.AfterReceiveRequest

Thread.CurrentPrincipal = new GenericPrincipal(new GenericIdentity(username, "Membership Provider"), roles);

我已经省略了验证码。

要从服务方法访问值，您可以调用

Thread.CurrentPrincipal.Identity.Name

于 2014-06-19T21:13:27.330 回答
1

我相信您不需要实现自定义IDispatchMessageInspector来检索自定义标头，它可以通过服务操作方法完成，如下所示：

var mp = OperationContext.Current.IncomingMessageProperties;
var property = (HttpRequestMessageProperty)mp[HttpRequestMessageProperty.Name];
var userName = property.Headers["Username"];

如果您想中止消息处理，例如如果缺少凭据，则实现自定义调度消息检查器是有意义的 - 在这种情况下您可以只抛出 FaultException。

但是，如果您仍然想将值从调度消息检查器传递给服务操作方法 - 可能它可以通过一些单例以及调用标识符（会话 id）传递，稍后通过方法提取，或者使用wcf 扩展

于 2014-06-19T20:56:49.210 回答
0

在您链接到的 MSDN 页面上，还描述了如何插入检查器以及一个示例。去引用：

通常，消息检查器由服务行为、端点行为或合同行为插入。然后，该行为将消息检查器添加到 DispatchRuntime.MessageInspectors 集合。

稍后您将获得以下示例：

  • 实现自定义 IDispatchMessageInspector
  • 实现将检查器添加到运行时的自定义 IServiceBehavior。
  • 通过 .config 文件配置行为。

这应该足以让你开始。否则随时问:)

如果您只想从您的服务中访问标头，您可以尝试OperationContext.Current.IncomingMessageHeaders.

于 2014-06-16T14:10:59.057 回答