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我正在努力实现以下目标。我创建了长时间运行的工作流,它们按预定的时间间隔唤醒,即延迟活动并执行它们的工作,填充缓存。这些工作流从主应用程序开始,这是一个 IIS 7 托管的自定义 WCF 数据服务。启动工作流的触发器因用户登录、特定实体的请求而异。

目前,我创建了一个 WCF 工作流服务,它侦听作为标准请求合同一部分的触发器。收到触发器后,它会使用活动定义实例化 WorkflowApplication 并启动工作流。然而,这有其局限性,因为必须手动完成持久性和补液。

我遇到了 WorkflowServiceHost 的示例,它可以充当在故障转移的情况下支持持久性和再水化的主机,因为我们有一个网络农场环境。但是,当我尝试执行以下操作时,它会因各种错误而失败。所以只是想知道,如果我朝着正确的方向前进。或者这是不可能的。请找到基于 MSDN 示例的 IWorkflowCreation 合约实现代码:

`  public Guid StartWorkflowReturnGuid(Dictionary<string,object> parameters)
        {
            Guid id = Guid.Empty;
            try
            {


            System.ServiceModel.Activities.WorkflowServiceHost host = new System.ServiceModel.Activities.WorkflowServiceHost(this.workflow, new Uri("net.pipe://localhost"));

            //string myConnectionString =
            //   "Data Source=localhost\\SQLEXPRESS;Initial Catalog=DefaultSampleStore;Integrated Security=True;Asynchronous Processing=True";
            //SqlWorkflowInstanceStoreBehavior sqlWorkflowInstanceStoreBehavior =
            //    new SqlWorkflowInstanceStoreBehavior(myConnectionString);
            //sqlWorkflowInstanceStoreBehavior.HostLockRenewalPeriod = TimeSpan.FromSeconds(30);
            //sqlWorkflowInstanceStoreBehavior.RunnableInstancesDetectionPeriod = TimeSpan.FromSeconds(30);
            //host.Description.Behaviors.Add(sqlWorkflowInstanceStoreBehavior);

            WorkflowUnhandledExceptionBehavior workflowUnhandledExceptionBehavior =
                new WorkflowUnhandledExceptionBehavior();

            workflowUnhandledExceptionBehavior.Action = WorkflowUnhandledExceptionAction.Terminate;

            //Set the TimeToUnload to 0 to force the WF to be unloaded. To have a durable delay, the WF needs to be unloaded otherwise it will be thread as an in-memory delay.
            //WorkflowIdleBehavior workflowIdleBehavior = new WorkflowIdleBehavior()
            //{
            //    TimeToUnload = TimeSpan.FromSeconds(0)
            //};
            //host.Description.Behaviors.Add(workflowIdleBehavior);
            host.WorkflowExtensions.Add(new LoginExtensions());
            host.WorkflowExtensions.Add(new MarketDataExtensions());
            ResumeBookmarkEndpoint endpoint = new ResumeBookmarkEndpoint(new NetNamedPipeBinding(NetNamedPipeSecurityMode.None), new EndpointAddress(string.Format("net.pipe://localhost/workflowCreationEndpoint/{0}",Guid.NewGuid())));
            host.AddServiceEndpoint(endpoint);
            host.Open();
            IWorkflowCreation client = new ChannelFactory<IWorkflowCreation>(endpoint.Binding, endpoint.Address).CreateChannel();
            //create an instance
            id = client.Create(parameters);
            Helper.LogInfo(string.Format("Workflow instance {0} created", id));
            }
            catch (Exception exception)
            {

                Helper.LogError(string.Format("Exception starting BatchWorkflowServiceHost for type {0}", this.workflow.GetType().FullName), exception);
            }
            return id;
        }
public class ResumeBookmarkEndpoint : WorkflowHostingEndpoint
{

    public ResumeBookmarkEndpoint(Binding binding, EndpointAddress address)
        : base(typeof(IWorkflowCreation), binding, address)
    {
    }

    protected override Guid OnGetInstanceId(object[] inputs, OperationContext operationContext)
    {
        //Create called
        if (operationContext.IncomingMessageHeaders.Action.EndsWith("Create"))
        {
            return Guid.Empty;
        }
        //CreateWithInstanceId or ResumeBookmark called. InstanceId is specified by client
        else if (operationContext.IncomingMessageHeaders.Action.EndsWith("CreateWithInstanceId")||
                operationContext.IncomingMessageHeaders.Action.EndsWith("ResumeBookmark"))
        {
            return (Guid)inputs[0];
        }
        else
        {
            throw new InvalidOperationException("Invalid Action: " + operationContext.IncomingMessageHeaders.Action);
        }
    }


    protected override WorkflowCreationContext OnGetCreationContext(object[] inputs, OperationContext operationContext, Guid instanceId, WorkflowHostingResponseContext responseContext)
    {
        WorkflowCreationContext creationContext = new WorkflowCreationContext();
        if (operationContext.IncomingMessageHeaders.Action.EndsWith("Create"))
        {
            Dictionary<string, object> arguments = (Dictionary<string, object>)inputs[0];
            if (arguments != null && arguments.Count > 0)
            {
                foreach (KeyValuePair<string, object> pair in arguments)
                {
                    //arguments for the workflow
                    creationContext.WorkflowArguments.Add(pair.Key, pair.Value);
                }
            }
            //reply to client with the InstanceId
            responseContext.SendResponse(instanceId, null);
        }
        else if (operationContext.IncomingMessageHeaders.Action.EndsWith("CreateWithInstanceId"))
        {
            Dictionary<string, object> arguments = (Dictionary<string, object>)inputs[0];
            if (arguments != null && arguments.Count > 0)
            {
                foreach (KeyValuePair<string, object> pair in arguments)
                {
                    //arguments for the workflow
                    creationContext.WorkflowArguments.Add(pair.Key, pair.Value);
                }
            }
        }
        else
        {
            throw new InvalidOperationException("Invalid Action: " + operationContext.IncomingMessageHeaders.Action);
        }
        return creationContext;
    }
    protected override System.Activities.Bookmark OnResolveBookmark(object[] inputs, OperationContext operationContext, WorkflowHostingResponseContext responseContext, out object value)
    {
        Bookmark bookmark = null;
        value = null;
        if (operationContext.IncomingMessageHeaders.Action.EndsWith("ResumeBookmark"))
        {
            //bookmark name supplied by client as input to IWorkflowCreation.ResumeBookmark
            bookmark = new Bookmark((string)inputs[1]);
            //value supplied by client as argument to IWorkflowCreation.ResumeBookmark
            value = (string) inputs[2];
        }
        else
        {
            throw new NotImplementedException(operationContext.IncomingMessageHeaders.Action);
        }
        return bookmark;
    }
}

//ServiceContract exposed on the endpoint
[ServiceContract(Name = "IWorkflowCreation")]
public interface IWorkflowCreation
{
    [OperationContract(Name = "Create")]
    Guid Create(IDictionary<string, object> inputs);

    [OperationContract(Name = "CreateWithInstanceId", IsOneWay=true)]
    void CreateWithInstanceId(Guid instanceId, IDictionary<string, object> inputs);

    [OperationContract(Name = "ResumeBookmark", IsOneWay = true)]
    void ResumeBookmark(Guid instanceId, string bookmarkName, string message);

}
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1 回答 1

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你想要做的当然是可能的。但是,您的问题提出了一个问题。您说您有 WCF 工作流服务,这意味着您已经在使用 WorkflowServiceHost。

就使用 WorkfowServiceHost 而言。使用 IWorkflowCreation 自己创建和管理工作流是可能的,有一些关于如何操作的示例,但通常的方法是使用 WCF-WF4 基础结构为您创建工作流。创建一个工作流,添加一个接收活动并将 CanCreateInstance 设置为 true,然后向该活动发送 WCF 请求将为您创建一个新的工作流实例。

如果您想使用具有持久性的 WorklflowApplication 也是可能的,但您必须自己管理每个实例。没有自动重新加载,如果您必须管理单个实例,那么您如何检查过期的计时器并恢复实例。故障转移也可以正常工作,它使用相同的 SqlWorkflowInstanceStore 来执行工作流状态的实际保存和加载。

于 2011-07-11T12:34:13.103 回答