ASP.NET SignalR HubPipelineModule

ASP.NET SignalR 1.0 實現的一個特性HubPipeline -實現任何訊息incoming和outgoing的攔截。SignalR HubPipeline功能對應的ASP.NET Web API和ASP.NET MVC的 ActionFilter。

下面的方法是作為一個實體在IHubPipelineModule定義：

public interface IHubPipelineModule{    Func<IHubIncomingInvokerContext, Task<object>> BuildIncoming(Func<IHubIncomingInvokerContext, Task<object>> invoke);    Func<IHubOutgoingInvokerContext, Task> BuildOutgoing(Func<IHubOutgoingInvokerContext, Task> send);    Func<IHub, Task> BuildConnect(Func<IHub, Task> connect);    Func<IHub, Task> BuildReconnect(Func<IHub, Task> reconnect);    Func<IHub, Task> BuildDisconnect(Func<IHub, Task> disconnect);    Func<HubDescriptor, IRequest, bool> BuildAuthorizeConnect(Func<HubDescriptor, IRequest, bool> authorizeConnect);    Func<HubDescriptor, IRequest, IList<string>, IList<string>> BuildRejoiningGroups(Func<HubDescriptor, IRequest, IList<string>, IList<string>> rejoiningGroups);}

是不是感覺有非常複雜的委託。不用急， HubPipelineModule 類已經為我們實現了大部分的功能，大部分情況下已經夠用了，可以繼承這個雷重寫裡面方法就可以了.

public abstract class HubPipelineModule : IHubPipelineModule{    protected virtual bool OnBeforeAuthorizeConnect(HubDescriptor hubDescriptor, IRequest request);    protected virtual bool OnBeforeConnect(IHub hub);    protected virtual void OnAfterConnect(IHub hub);    protected virtual bool OnBeforeReconnect(IHub hub);    protected virtual void OnAfterReconnect(IHub hub);    protected virtual bool OnBeforeOutgoing(IHubOutgoingInvokerContext context);    protected virtual void OnAfterOutgoing(IHubOutgoingInvokerContext context);    protected virtual bool OnBeforeDisconnect(IHub hub);    protected virtual void OnAfterDisconnect(IHub hub);    protected virtual bool OnBeforeIncoming(IHubIncomingInvokerContext context);    protected virtual object OnAfterIncoming(object result, IHubIncomingInvokerContext context);    protected virtual void OnIncomingError(Exception ex, IHubIncomingInvokerContext context);}

這代碼看起來是不是和ASP.NET Web API和ASP.NET MVC的 ActionFilter 很相似呢。如果其中稱為OnBefore的方法返回false，它會立即結束。

public class AntiClickModule : HubPipelineModule{    public AntiClickModule()    {        Interval = 1000;    }    public int Interval { get; set; }    private readonly ConcurrentDictionary<string, DateTime> _connections = new ConcurrentDictionary<string, DateTime>();    protected override void OnAfterDisconnect(IHub hub)    {        DateTime lastDateTime;        _connections.TryRemove(hub.Context.ConnectionId, out lastDateTime);    }    protected override bool OnBeforeIncoming(IHubIncomingInvokerContext context)    {        var now = DateTime.Now;        var connectionId = context.Hub.Context.ConnectionId;        DateTime lastDateTime;        if (_connections.TryGetValue(connectionId, out lastDateTime))        {            var span = now - lastDateTime;            if (span.TotalMilliseconds < Interval)            {                return false;            }        }        _connections.AddOrUpdate(connectionId, now, (_, __) => now);        return true;    }}

記錄下串連到每個ID所請求的時間，我們簡單地檢查下一個請求的時間間隔。  如果2個請求之間的時間差小於我們設定的時間間隔，直接返回。

您可以把它添加到使用GlobalHost的模組Global.asax.cs

protected void Application_Start(object sender, EventArgs e){    GlobalHost.HubPipeline.AddModule(new AntiClickModule());}