Asp.net: deny frequent IP Access

// First, we need to implement the ihttpmodule Interface

Using system;
Using system. Collections. Generic;
Using system. text;
Using system. Web;
Using system. Web. UI;
Using system. Web. sessionstate;
Using system. configuration;

namespace myhttp
{< br> public class urlrewrite: ihttpmodule
{< br> ///

/// maximum number of connections allowed for a single IP address
///
private int rowcount = convert. toint32 (configurationsettings. appsettings ["httprowcount"]);
///
// time range of the specified region
///
private int httptime = convert. toint32 (configurationsettings. appsettings ["httptime"]);

Public void Init (httpapplication Application)
{
Application. beginrequest + = (New
Eventhandler (this. application_beginrequest ));
Application. endrequest + = (New
Eventhandler (this. application_endrequest ));

}
Private void application_beginrequest (Object source, eventargs E)
{
Httpapplication application = (httpapplication) source;
Httpcontext CTX = application. context;
// Ip address
String isip = CTX. Request. userhostaddress;
If (CTX. application ["time"] = NULL)
{
CTX. application ["time"] = datetime. now;
}
Else
{
Datetime Istime = (datetime) CTX. application ["time"];
Int timetract = convert. toint32 (datetime. Now. Subtract (Istime). Minutes. tostring ());
If (timetract> (httptime-1 ))
{
CTX. application ["time"] = NULL;
CTX. application ["myip"] = NULL;
}
}
If (CTX. application ["myip"]! = NULL & CTX. application ["myip"] Is cartip)
{
Cartip = (cartip) CTX. application ["myip"];
Cartip. insert (isip );
CTX. application ["myip"] = cartip;
If (cartip. getcount (isip)> rowcount)
{
CTX. response. Clear ();
CTX. response. Close ();
}
}
Else
{
Cartip = new cartip ();
Cartip. insert (isip );
Httpcontext. Current. application ["myip"] = cartip;
}
}

Private void application_endrequest (Object source, eventargs E)
{

}

Public void dispose ()
{

}

}
}

 

// Listip class

 

Using system;
Using system. Collections. Generic;
Using system. text;

Namespace myhttp
{
[Serializable]
Public class listip
{
Private string IP;
Private int count;
/// <Summary>
/// IP Address
/// </Summary>
Public String IP
{
Get {return IP ;}
Set {IP = value ;}
}
/// <Summary>
/// Accumulative quantity
/// </Summary>
Public int count
{
Get {return count ;}
Set {COUNT = value ;}
}
}
[Serializable]
Public class cartip
{
Public cartip ()
{
If (_ listip = NULL)
{
_ Listip = new list <listip> ();
}
}
Private list <listip> _ listip;
Public list <listip> _ listip
{
Get {return _ listip ;}
Set {_ listip = value ;}
}
/// <Summary>
/// Add an IP address
/// </Summary>
Public void insert (string IP)
{
Int indexof = itemlastinfo (IP );
If (indexof =-1)
{
// Does not exist
Listip item = new listip ();
Item. IP = IP;
_ Listip. Add (item );
}
Else
{
_ Listip [indexof]. Count + = 1;
}
}
// Determine whether an IP exists
Public int itemlastinfo (string IP)
{
Int Index = 0;
Foreach (listip item in _ listip)
{
If (item. IP = IP)
{
Return Index; // Yes
}
Index + = 1;
}
Return-1; // does not exist
}
/// <Summary>
/// Number of IP addresses obtained
/// </Summary>
/// <Param name = "ip"> </param>
/// <Returns> </returns>
Public int getcount (string IP)
{
Foreach (listip item in _ listip)
{
If (item. IP = IP)
{
Return item. Count; // Yes
}
}
Return-1; // does not exist
}
}
}

 

 

// Configure access rules in Web. config

<Deleetask>

<Add key = "httprowcount" value = "100"/>
<Add key = "httptime" value = "10"/>

</Appsettings>

 

<System. Web>

<Httpmodules>
<Add name = "urlrewrite" type = "myhttp. urlrewrite"/>
</Httpmodules>
</System. Web>