要创建自定义模块，类需要实现IHttpModule接口。这个接口定义了Init和Dispose方法。
Init方法在启动Web应用程序时调用，其参数的类型是HttpContext，可以添加应用程序处理事件。
新建类库ModuleSample,新建类SampleModule添加如下代码：
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Web; namespace ModuleSample
{
public class SampleModule : IHttpModule
{
private const string allowAddressesFile = "AllowedAddresses.txt";
private List<string> allowAddressesList;
public void Dispose()
{
throw new NotImplementedException();
} public void Init(HttpApplication context)
{
context.LogRequest += new EventHandler(OnLogRequest);
context.BeginRequest += BeginRequest;
context.PreRequestHandlerExecute += PreRequestHandlerExecute;
} private void BeginRequest(object sender, EventArgs e)
{
LoadAddresses((sender as HttpApplication).Context);
}
private void LoadAddresses(HttpContext context)
{
if (allowAddressesList == null)
{
string path = context.Server.MapPath(allowAddressesFile);
allowAddressesList = File.ReadAllLines(path).ToList();
}
}
private void PreRequestHandlerExecute(object sender, EventArgs e)
{
HttpApplication app = sender as HttpApplication;
HttpRequest request = app.Context.Request;
if (!allowAddressesList.Contains(request.UserHostAddress))
{
throw new HttpException(403, "IP address denied");
}
}
public void OnLogRequest(Object source, EventArgs e)
{
//custom logging logic can go here
}
}
}
在WebConfig中配置：
<system.webServer>
<handlers>
<add name="CustomHandler" verb="*" path="CallCustomHandler" type="SampleHandler.CustomHandler,SampleHandler"/>
<add name="InfoHandler" verb="GET" path="CallInfoHandler.axd" type="SampleHandler.InfoHandler,SampleHandler"/>
</handlers>
<modules>
<add name="SampleModule" type="ModuleSample.SampleModule,ModuleSample"/>
</modules>
</system.webServer>
程序执行图：
运行时