HttpModule implementation of System IP access control detailed

A recent project in a government system requires configurable IP access control, since there is this demand we naturally have to meet.

For the previous article in the use of IHttpHandlerFactory authentication user experience, this time using HttpModule to detect users earlier.

How to better judge whether the IP in the Allowed list or banned list, based on the current IPV4, simply IP 4-bit field to judge separately, this can also be a simple batch of IP network settings.

The configuration is saved to the database in the system, and the database is designed as follows:

Next you can write HttpModule, as follows:

public　class　IPHttpModule　:　IHttpModule
{
#region　 IHttpModule　成员
public　void　Dispose()
{
}
public　void 　Init(HttpApplication　context)
{
context.BeginRequest　+=　new 　EventHandler(context_BeginRequest);
}
#endregion
///
/// 　提示信息
///
const　string　ErrorHtml　=　@"
您的访问受到限 制，请与系统管理员联系。
";
void　context_BeginRequest(object　 sender,　EventArgs　e)
{
HttpApplication　app　=　 (HttpApplication)sender;
HttpContext　context　=　app.Context;
// 判断是否IP限制
if　(!CheckPermisssion (context.Request.UserHostAddress))
{
context.Response.Write (ErrorHtml);
context.Response.End();
}
}
}