How to migrate IHttpHandler and IHttpModule to ASP.NET Core middleware

Ordinary programmer 2022-09-23 07:47:46 阅读数:195

migrateihttphandlerihttpmoduleasp.netasp

ASP.NET Core是一个跨平台、开源的框架,用于在Windows、Mac和Linux操作系统(OS)上开发web应用程序.你可以使用以下任何IDE开发ASP.NET Core 应用程序:

  • Visual Studio
  • Visual Studio for Mac
  • Visual Studio Code

在这篇博文中,我们将学习如何如何将asp.net IHttpHandler和IHttpModule迁移到ASP.NET Core中间件并提供代码示例.

让我们开始吧!

ASP.NET IHttpHandler

在ASP.NET应用程序中,HTTP处理程序是一个进程,它在对向web服务器的每个响应上执行.我们可以创建自己的自定义HTTP处理程序.

下面是将所有.aspx页重定向到一个新页的代码.

public class RedirectionHandler : IHttpHandler
{
public bool IsReusable
{
get { return false; }
}
public void ProcessRequest(HttpContext context)
{
var response = context.Response;
response.Write("<p>Process files with .aspx extension</p>");
// Any redirection logic can be written here.
}
}

web.config中添加如下代码:

<add name="RedirectionHandler" verb="*" path="*.aspx" type="MyWebApplication.RedirectionHandler" resourceType="Unspecified"/>

ASP.NET IHTTPModule

IHttpModule还将在应用程序的每个请求的HTTP处理程序执行之前和之后.它们帮助我们验证传入和传出的请求并修改它们.

下面是用于根据用户的IP地址限制用户的IHttpModule代码.

public class IPRestrictionModule : IHttpModule
{
public void Init(HttpApplication context)
{
context.BeginRequest += (source, arguments) =>
{
var application = (HttpApplication)source;
var beginContext = application.Context;
beginContext.Response.Write("<p>Restrict Users based on IP</p>");
// Code logic comes here.
};
context.EndRequest += (source, arguments) =>
{
var application = (HttpApplication)source;
var endContext = application.Context;
endContext.Response.Write("<p>Request ended.</p>");
};
}
}

web.config中添加如下代码:

<add name="RestrictionModule" type=" MyWebApplication.IPRestrictionModule" />

ASP.NET Core中间件

在ASP.NET Core应用程序中,中间件组件将替换IHttpHandler和IHttpModule.它是针对每个请求执行的组件.我们可以使用IApplicationBuilder接口在Startup类的Configure方法中添加中间件.

可以使用以下四种方法:

Run

终止HTTP管道.

Use

将中间件添加到请求管道.

Map

根据请求路径匹配请求委托

MapWhen

支持基于谓词的中间件分支.

让我们看看如何将ASP.NET IHttpHandler和IHttpModule迁移到ASP.NET Core中间件!

将 IHttpHandler迁移到ASP.NET Core中间件

1. 使用如下代码创建RedirectionHandlerMiddleware 类

public class RedirectionHandlerMiddleware
{
private RequestDelegate _next;
public RedirectionHandlerMiddleware(RequestDelegate next)
{
_next = next;
}
public async Task Invoke(HttpContext context)
{
await context.Response.WriteAsync("<p>Process files with .aspx extension</p>");
// Any Redirection logic can be return here.
}
}

2. 在ApplicationBuilder中创建一个扩展方法,以在请求管道中使用RedirectionHandlerMiddleware.

3. 然后,为扩展方法创建一个名为MiddlewareExtension的类,并在其中使用以下代码.

public static class MiddlewareExtension
{
public static IApplicationBuilder UseRedirectionHanlderMiddleware
(this IApplicationBuilder applicationBuilder)
{
return applicationBuilder.UseMiddleware<RedirectionHandlerMiddleware>();
}
}

4. 我们需要在Startup.cs文件中包含下一个代码.

app.MapWhen(context => context.Request.Path.ToString().EndsWith(".aspx"),
appBuilder => {
appBuilder.UseRedirectionHanlderMiddleware();
});

​​​​​​​现在,我们已经完成了IHttpHandler的迁移.

将 IHttpModule迁移到ASP.NET Core中间件

1. 使用如下代码创建IPRestrictionModuleMiddleware类.​​​​​​​

public class IPRestrictionModuleMiddleware
{
private RequestDelegate _next;
public IPRestrictionModuleMiddleware (RequestDelegate next)
{
_next = next;
}
public async Task Invoke(HttpContext context)
{
await context.Response.WriteAsync("<p>Begin request</p>");
await _next.Invoke(context);
await context.Response.WriteAsync("<p>End request</p>");
}
}

2. 与之前一样,我们需要添加一个扩展方法用来在请求管道中添加中间件.

3. 然后,向现有的MiddlewareExtension类中添加以下代码:​​​​​​​

public static class MiddlewareExtensions
{
public static IApplicationBuilder UseRedirectionHanlderMiddleware
(this IApplicationBuilder applicationBuilder)
{
return applicationBuilder.UseMiddleware<RedirectionHandlerMiddleware>();
}
public static IApplicationBuilder UseIPRestrictionModuleMiddleware
(this IApplicationBuilder builder)
{
return builder.UseMiddleware<IPRestrictionModuleMiddleware>();
}
}

4. 然后,将中间件包含在Startup.cs文件中.​​​​​​​

// For Module
app.UseIPRestrictionModuleMiddleware();
// For Handler
app.MapWhen(context => context.Request.Path.ToString().EndsWith(".aspx"),
appBuilder => {
appBuilder.UseRedirectionHanlderMiddleware();
});

这样,我们就完成了对IHttpModule的迁移.

原文链接:https://www.syncfusion.com/blogs/post/how-to-migrate-asp-net-http-handlers-and-modules-to-asp-net-core-middleware.aspx

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