Appfabric WF4-WCF services, how to retrieve current url in codeactivity without httpcontext?

问题

I have developed a wf-wcf services with a code activity and in it I want to retrieve the current URL of the service. If I'm disabling the persistence feature of appfabric I can retrieve the URL using

HttpContext.Current.Request.Url.ToString()

If the persistence feature is enabled then the httpcontext is null.

Is there a different way to retrieve the URL of the WCF that hosts my code activity?

回答1:

You need to implment IReceiveMessageCallback and add that to an activity's context. In the OnReceiveMessage you get passed the current OperationContext allowing you to inspect the incoming message.

This WF4 samples shows how to do this.

Example code:

using System.Activities;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.ServiceModel.Activities;

namespace DeclarativeServiceLibrary2
{
    public sealed class GetWCFMessageTo : NativeActivity
    {
        public Receive Receive { get; set; }

        public OutArgument<string> WcfTo { get; set; }

        protected override void Execute(NativeActivityContext context)
        {
            context.Properties.Add("ReceiveMessageCallback", new ReceiveMessageCallback());
            context.ScheduleActivity(Receive, CompletionCallback);
        }

        private void CompletionCallback(NativeActivityContext context, ActivityInstance completedInstance)
        {
            var receiveMessageCallback = context.Properties.Find("ReceiveMessageCallback") as ReceiveMessageCallback;
            WcfTo.Set(context, receiveMessageCallback.WcfRequestTo);
        }
    }

    [DataContract]
    class ReceiveMessageCallback : IReceiveMessageCallback
    {
        public string WcfRequestTo { get; private set; }

        public void OnReceiveMessage(OperationContext operationContext, ExecutionProperties activityExecutionProperties)
        {
            WcfRequestTo = operationContext.RequestContext.RequestMessage.Headers.To.ToString();
        }
    }
}

and the sample workflow XAMLX

<WorkflowService mc:Ignorable="sap" ConfigurationName="Service1" sap:VirtualizedContainerService.HintSize="307,306" Name="Service1" mva:VisualBasic.Settings="Assembly references and imported namespaces serialized as XML namespaces" xmlns="http://schemas.microsoft.com/netfx/2009/xaml/servicemodel" xmlns:d="clr-namespace:DeclarativeServiceLibrary2;assembly=DeclarativeServiceLibrary2" xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" xmlns:mv="clr-namespace:Microsoft.VisualBasic;assembly=System" xmlns:mva="clr-namespace:Microsoft.VisualBasic.Activities;assembly=System.Activities" xmlns:p="http://tempuri.org/" xmlns:p1="http://schemas.microsoft.com/netfx/2009/xaml/activities" xmlns:s="clr-namespace:System;assembly=mscorlib" xmlns:s1="clr-namespace:System;assembly=System" xmlns:s2="clr-namespace:System;assembly=System.Xml" xmlns:s3="clr-namespace:System;assembly=System.Core" xmlns:s4="clr-namespace:System;assembly=System.ServiceModel" xmlns:sa="clr-namespace:System.Activities;assembly=System.Activities" xmlns:sad="clr-namespace:System.Activities.Debugger;assembly=System.Activities" xmlns:sap="http://schemas.microsoft.com/netfx/2009/xaml/activities/presentation" xmlns:scg="clr-namespace:System.Collections.Generic;assembly=System" xmlns:scg1="clr-namespace:System.Collections.Generic;assembly=System.ServiceModel" xmlns:scg2="clr-namespace:System.Collections.Generic;assembly=System.Core" xmlns:scg3="clr-namespace:System.Collections.Generic;assembly=mscorlib" xmlns:sd="clr-namespace:System.Data;assembly=System.Data" xmlns:sl="clr-namespace:System.Linq;assembly=System.Core" xmlns:st="clr-namespace:System.Text;assembly=mscorlib" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <p1:Sequence DisplayName="Sequential Service" sad:XamlDebuggerXmlReader.FileName="c:\temp\DeclarativeServiceLibrary2\DeclarativeServiceLibrary2\Service1.xamlx" sap:VirtualizedContainerService.HintSize="277,276" mva:VisualBasic.Settings="Assembly references and imported namespaces serialized as XML namespaces">
    <p1:Sequence.Variables>
      <p1:Variable x:TypeArguments="CorrelationHandle" Name="handle" />
      <p1:Variable x:TypeArguments="x:Int32" Name="data" />
      <p1:Variable x:TypeArguments="x:String" Name="WcfRequestTo" />
    </p1:Sequence.Variables>
    <sap:WorkflowViewStateService.ViewState>
      <scg3:Dictionary x:TypeArguments="x:String, x:Object">
        <x:Boolean x:Key="IsExpanded">True</x:Boolean>
      </scg3:Dictionary>
    </sap:WorkflowViewStateService.ViewState>
    <d:GetWCFMessageTo sap:VirtualizedContainerService.HintSize="255,22" WcfTo="[WcfRequestTo]">
      <d:GetWCFMessageTo.Receive>
        <Receive x:Name="__ReferenceID0" CanCreateInstance="True" DisplayName="ReceiveRequest" sap:VirtualizedContainerService.HintSize="255,90" OperationName="GetData" ServiceContractName="p:IService">
          <Receive.CorrelationInitializers>
            <RequestReplyCorrelationInitializer CorrelationHandle="[handle]" />
          </Receive.CorrelationInitializers>
          <ReceiveMessageContent>
            <p1:OutArgument x:TypeArguments="x:Int32">[data]</p1:OutArgument>
          </ReceiveMessageContent>
        </Receive>
      </d:GetWCFMessageTo.Receive>
    </d:GetWCFMessageTo>
    <SendReply Request="{x:Reference __ReferenceID0}" DisplayName="SendResponse" sap:VirtualizedContainerService.HintSize="255,90">
      <SendMessageContent>
        <p1:InArgument x:TypeArguments="x:String">["Received " &amp; data &amp; " WCF To header: " &amp; WcfRequestTo]</p1:InArgument>
      </SendMessageContent>
    </SendReply>
  </p1:Sequence>
</WorkflowService>

来源：https://stackoverflow.com/questions/2765072/appfabric-wf4-wcf-services-how-to-retrieve-current-url-in-codeactivity-without