ASP.NET SignalR HubPipelineModule

ASP.NET SignalR 1.0 实现的一个特性HubPipeline -实现任何消息incoming和outgoing的拦截。SignalR HubPipeline功能对应的ASP.NET Web API和ASP.NET MVC的 ActionFilter。

下面的方法是作为一个实体在IHubPipelineModule定义：

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);
}

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是不是感觉有非常复杂的委托。不用急， HubPipelineModule 类已经为我们实现了大部分的功能，大部分情况下已经够用了，可以继承这个雷重写里面方法就可以了.

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);
}

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{
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color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
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这代码看起来是不是和ASP.NET Web API和ASP.NET MVC的 ActionFilter 很相似呢。如果其中称为OnBefore的方法返回false，它会立即结束。

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;
}
}

记录下连接到每个ID所请求的时间，我们简单地检查下一个请求的时间间隔。  如果2个请求之间的时间差小于我们设定的时间间隔，直接返回。

您可以把它添加到使用GlobalHost的模块Global.asax.cs

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

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }