Refine：带有 PerSession InstanceContext 的 WCF Castle ActiveRecord SessionScope 实现

Question

为了促进使用 AR 的 WCF 服务的延迟加载，我为 WCF 创建了“Session Scope PerRequest”解决方案。

如果您想在网站或 Web 服务中使用 ActiveRecord，您必须通过它在 Web 环境中运行的配置来告诉它。

它无论如何假设它将有一个 WCF 中不存在的 HttpContext.Current 。

因此，我们告诉 AR 使用我们自己的 AbstractThreadScopeInfo 实现，该实现还实现了 IWebThreadScopeInfo，以告诉它它与“每请求会话”模式兼容，该模式如今已成为“每会话会话”模式。

添加了一些对我遇到的延迟加载异常的修复 这里

public class WCFThreadScopeInfo : AbstractThreadScopeInfo, IWebThreadScopeInfo
{

    public static readonly ILog Logger = LogManager.GetLogger (typeof (WCFThreadScopeInfo));

    private readonly object _syncLock;

    public WCFThreadScopeInfo()
    {
        _syncLock = new object ();
    }

    public new void RegisterScope (ISessionScope scope)
    {
        CurrentStack.Push (scope);
    }

    public new ISessionScope GetRegisteredScope ()
    {
        if (CurrentStack.Count == 0)
        {
            //Instead of returning a "null" stack as is in the original ActiveRecord code, 
            //instantiate a new one which adds itself to the stack immediately
            lock (_syncLock)
            {
                if (CurrentStack.Count == 0)
                {
                    new SessionScope ();
                }
            }
        }
        return CurrentStack.Peek () as ISessionScope;
    }

    public new void UnRegisterScope (ISessionScope scope)
    {
        if (GetRegisteredScope () != scope)
        {
            throw new ScopeMachineryException ("Tried to unregister a scope that is not the active one");
        }
        CurrentStack.Pop ();
    }

    public new bool HasInitializedScope
    {
        get { return GetRegisteredScope () != null; }
    }


    #region Overrides of AbstractThreadScopeInfo
    public override Stack CurrentStack
    {
        [MethodImpl(MethodImplOptions.Synchronized)]
        get
        {
            //Lets use the OperationContext instead of the HttpContext
            OperationContext current = OperationContext.Current;

            //Which offcourse can't be null
            if (current == null)
                throw new ScopeMachineryException ("Could not access OperationContext.Current");

            //Get the first WCF StackContainer from the OperationContext or null
            WCFStackContainer stackContainer = (WCFStackContainer)current.Extensions.FirstOrDefault (ex => ex is WCFStackContainer);

            //If the previous statement didn't find any add a new one to the OperationContext
            if (stackContainer == null)
            {
                Logger.Debug ("Creating new WCFStackContainer");
                stackContainer = new WCFStackContainer ();
                current.Extensions.Add (stackContainer);
            }

            //In the end return the stack in the container
            return stackContainer.Stack;
        }
    }
    #endregion
}

正如你在上面看到的，我们需要一个可以添加到当前OperationContext.Extensions中的WCFStackContainer。为了促进这一点，它需要实现 IExtension。请参阅此处：

public class WCFStackContainer : IExtension<OperationContext>
{
    private Stack _stack;

    public Stack Stack 
    {
        get { return _stack; }
        set { _stack = value; }
    }

    #region Implementation of IExtension<OperationContext>

    public void Attach (OperationContext owner)
    {
        //On Attachment to the OperationContext create a new stack.
        _stack = new Stack();
    }

    public void Detach (OperationContext owner)
    {
        _stack = null;
    }

    #endregion
}

现在我们为具有 HttpContext 的 Web 应用程序替换了 IsWebApp 功能。现在我们需要识别会话。

因此，如果我们有一个 HttpContext，我们会执行类似的操作

.ctor 
{
    HttpContext.Current.Items.Add ("ar.sessionscope", new SessionScope());
}

public void Dispose ()
{
    try
    {
        SessionScope scope = HttpContext.Current.Items["ar.sessionscope"] as SessionScope;

        if (scope != null)
        {
            scope.Dispose ();
        }
    }
    catch (Exception ex)
    {
        CTMLogger.Fatal("Error " + "EndRequest: " + ex.Message, ex);
    }
}

这在 WCF 中无法完成 所以您需要类似的操作：

public class ARSessionWCFExtension : IExtension<OperationContext> 
{
    private static readonly ILog Logger = LogManager.GetLogger (typeof(ARSessionWCFExtention));
    private SessionScope _session;

    #region IExtension<OperationContext> Members

    public void Attach (OperationContext owner)
    {
        Logger.Debug ("Attachig ARSessionScope to WCFSession");
        _session = new SessionScope();
    }

    public void Detach (OperationContext owner)
    {
        try
        {
            Logger.Debug ("Detaching ARSessionScope from WCFSession");
            if (_session != null)
                _session.Dispose ();
        }
        catch(Exception ex)
        {
            Logger.Fatal ("Exception: " + ex.Message + " Stacktrace: " + ex.StackTrace);
        }
    }

    #endregion
}

我已经明白了这一点！还有更多:)

因此，在 WCFService 中，我们这样做：

.ctor
{
    OperationContext.Current.Extensions.Add(new ARSessionWCFExtension());
}

在 IDisposable 实现中，我们添加了这个。我们很高兴:)

    public void Dispose()
    {
        try 
        {
            foreach (var extension in OperationContext.Current.Extensions.Where (ex => ex is ARSessionWCFExtention).ToList ())
                OperationContext.Current.Extensions.Remove (extension);

            Logger.Debug ("Session disposed ClinicID: " + _currentClinic.ClinicID);
        } 
        catch (Exception ex)
        {
            Logger.Fatal ("Exception message: " + ex.Message + " StackTrace: " + ex.StackTrace);
        }
    }

但是它不起作用，OperationContext.Current 为空！。我在 MSDN 上进行了数小时毫无意义的搜索后发现没有 OperationContext 因为“OperationContext 仅在代码由客户端启动时才可用”

我现在通过将当前的 OperationContext 和 SessionID 存储在构造函数中解决了这个问题并在解构器中比较它们，然后使用它们来处理会话。

所以我现在有：

.ctor
{
    _current = OperationContext.Current;
    _sessionID = OperationContext.Current.SessionId;

    OperationContext.Current.Extensions.Add (new ARSessionWCFExtention ());
}

public void Dispose()
{
    try 
    {
        OperationContext.Current = _current;
        if (OperationContext.Current.SessionId != _sessionID)
            throw new Exception("v weird!");

        foreach (var extension in OperationContext.Current.Extensions.Where (ex => ex is ARSessionWCFExtention).ToList ())
            OperationContext.Current.Extensions.Remove (extension);

        Logger.Debug ("Session disposed ClinicID: " + _currentClinic.ClinicID);
    } 
    catch (Exception ex)
    {
        Logger.Fatal ("Exception message: " + ex.Message + " StackTrace: " + ex.StackTrace);
    }
}

有人知道我如何才能更强大/更好/更好地解决这个问题吗？

我尝试处理 OperationContext.Channel.Close 事件，但这不仅仅在客户端触发。每次完成调用后，OperationContext.OperationComplete 事件都会触发。这不是我们想要的，我们希望 AR 会话持续 WCFSession 的长度。