以编程方式将自定义 WCF 标头添加到端点以实现可靠会话

Question

我正在构建一个 WCF 路由器，我的客户端使用可靠会话。在这种情况下，当客户端打开通道时，会发送一条消息（建立可靠会话？）。其内容如下：

<s:Envelope xmlns:s="http://www.w3.org/2003/05/soap-envelope" xmlns:a="http://www.w3.org/2005/08/addressing">
  <s:Header>
    <a:Action s:mustUnderstand="1">http://docs.oasis-open.org/ws-rx/wsrm/200702/CreateSequence</a:Action>
    <a:MessageID>urn:uuid:1758f794-c5d3-4573-b252-7a07344cc257</a:MessageID>
    <a:To s:mustUnderstand="1">http://localhost:8010/RouterService</a:To>
  </s:Header>
  <s:Body>
    <CreateSequence xmlns="http://docs.oasis-open.org/ws-rx/wsrm/200702">
      <AcksTo>
        <a:Address>http://www.w3.org/2005/08/addressing/anonymous</a:Address>
      </AcksTo>
      <Offer>
        <Identifier>urn:uuid:64a12658-71d9-4967-88ec-9bb0610f7ecb</Identifier>
        <Endpoint>
          <a:Address>http://www.w3.org/2005/08/addressing/anonymous</a:Address>
        </Endpoint>
        <IncompleteSequenceBehavior>DiscardFollowingFirstGap</IncompleteSequenceBehavior>
      </Offer>
    </CreateSequence>
  </s:Body>
</s:Envelope>

这里的问题是标头不包含任何我可以用来查找将消息路由到哪个服务的信息。在 Busatmante 的路由器示例代码中，她通过向端点添加标头来解决此问题：

  <client>
    <endpoint address="http://localhost:8010/RouterService" binding="ws2007HttpBinding"
      bindingConfiguration="wsHttp"
      contract="localhost.IMessageManagerService" >
      <headers>
        <Route xmlns="http://www.thatindigogirl.com/samples/2008/01" >http://www.thatindigogirl.com/samples/2008/01/IMessageManagerService</Route>
      </headers>
    </endpoint>
  </client>

当打开可靠会话时，消息包含此自定义标头。

<Route a:IsReferenceParameter="true" xmlns="http://www.thatindigogirl.com/samples/2008/01">http://www.thatindigogirl.com/samples/2008/01/IMessageManagerService</Route>

这太棒了；但是，我需要以编程方式配置客户端。我认为 ChannelFactory Endpoint 将有一个 Header 对象，我可以手动添加自定义标头。不幸的是事实并非如此。因此，我做了一些搜索，发现了一些通过实现 IClientMessageInspector 来添加我的标头并将其作为行为添加到我的端点来扩展 WCF 的建议。

public class ContractNameMessageInspector : IClientMessageInspector {

    private const string HEADER_NAME = "ContractName";
    private readonly string _ContractName;

    public ContractNameMessageInspector(string contractName) {
        _ContractName = contractName;
    }

    #region IClientMessageInspector Members

    public void AfterReceiveReply(ref Message reply, object correlationState) { }

    public object BeforeSendRequest(ref Message request, IClientChannel channel) {

        HttpRequestMessageProperty httpRequestMessage;
        object httpRequestMessageObject;

        if (request.Properties.TryGetValue(HttpRequestMessageProperty.Name, out httpRequestMessageObject)) {
            httpRequestMessage = httpRequestMessageObject as HttpRequestMessageProperty;
            if (httpRequestMessage != null && string.IsNullOrEmpty(httpRequestMessage.Headers[HEADER_NAME])) {
                httpRequestMessage.Headers[HEADER_NAME] = this._ContractName;
            }
        }
        else {
            httpRequestMessage = new HttpRequestMessageProperty();
            httpRequestMessage.Headers.Add(HEADER_NAME, this._ContractName);
            request.Properties.Add(HttpRequestMessageProperty.Name, httpRequestMessage);
        }
        return null;
    }

    #endregion
}

因此，当我的客户端进行服务调用时，消息包含自定义标头，但建立可靠会话的消息仍然不包含。

所以我的问题是；如何以编程方式将自定义标头添加到端点，以便可靠会话消息包含它？

非常感谢

Answer 1

想通了。尽管没有属性或方法可以将标头添加到 EndpointAddress，但构造函数上有一个可选参数。

_Binding = bindingFactory.GetBinding(serviceUri, typeof(T));
AddressHeader header = AddressHeader.CreateAddressHeader("ContractName", "NameSpace", typeof (T).ToString());

_Address = new EndpointAddress(serviceUri, header);
_ChannelFactory = new ChannelFactory<T>(_Binding, _Address);

现在，当我收到建立可靠会话的消息时，它实际上包含我的自定义标头。这是有道理的，因为消息检查器很可能只对分派的消息进行操作，而建立可靠会话的消息是由较低级别的 WCF 代码生成的。

Answer 2

这对我有用

   public TResult Invoke<TResult>(Func<TClient, TResult> func,MessageHeader header)
    {
        TClient client = default(TClient);
        var sw = new Stopwatch();
        try
        {
            sw.Start();
            using (client = _channelFactory.CreateChannel())
            {
               using (OperationContextScope contextScope = new OperationContextScope(client))
                {
                    OperationContext.Current.OutgoingMessageHeaders.Add(header);

                    return func.Invoke(client);
                }
            }
        }
        finally
        {
            CloseConnection(client);
            Instrument(this.GetType().Name, sw);
        }
    }

Answer 3

要以编程方式添加地址标头，请参阅 MSDN 的 地址标头 其中可以以编程方式添加标头，例如：

var cl = new MyWCFClientContext();

var eab = new EndpointAddressBuilder(cl.Endpoint.Address);

eab.Headers.Add( AddressHeader.CreateAddressHeader("ClientIdentification", // Header Key
                                                    string.Empty,           // Namespace
                                                    "JabberwockyClient"));  // Header Value

cl.Endpoint.Address = eab.ToEndpointAddress();