ASP.NET 2.0 HttpHandler实现对某种文件类型权限保护(示例代码下载)

(一). HttpHandlers能够处理对某种特定文件类型的请求. 例如, 在machine.config 文件中默认已经有大部分的系统处理Handlers： <httpHandlers>    <add verb=”*” path=”*.aspx” type=”System..Web.UI.PageHandlerFactory” />    <add verb=”*” path=”*.ascx” type=”System..Web.HttpForbiddenHandler” />    <add verb=”*” path=”*.cs” type=” System..Web.HttpForbiddenHandler” />    <add verb=”*” path=”*.skin” type=” System..Web.HttpForbiddenHandler” />    <add verb=”*” path=”*.sitemap” type=” System..Web.HttpForbiddenHandler” />    ……. </httpHandlers> 创建一个HttpHandler也非常简单，下面将创建一个自定义的HttpHandler, 功能为验证访问: *.jpeg/jpg 图像文件权限. 通过这个示例演示其用法. (二).代码如下  1. 处理程序HttpHandler文件 JpgHandler.cs 代码     1  using  System;  2  using  System.Data;  3  using  System.Configuration;  4  using  System.Web;  5  using  System.Web.Security;  6  using  System.Web.UI;  7  using  System.Web.UI.WebControls;  8  using  System.Web.UI.WebControls.WebParts;  9  using  System.Web.UI.HtmlControls; 10  11  ///   <summary> 12  ///   只有 admin 权限用户才能直接查看 JPG和JPEG的图片 13  ///   </summary> 14  public   class  JpgHandler : IHttpHandler 15  { 16       public  JpgHandler() 17      {     18      }     19  public   void  ProcessRequest(HttpContext hc) 20      { 21           string  strFileName  =  hc.Server.MapPath( hc.Request.FilePath ); 22           if  (hc.User.IsInRole( " admin " ))   // 当前用户是否为 admin 权限 23          { 24              hc.Response.ContentType  =   " image/JPEG " ; 25              hc.Response.WriteFile(strFileName); 26          } 27           else 28          { 29              hc.Response.ContentType  =   " image/JPEG " ; 30              hc.Response.Write( " No Right " ); 31          }        32      } 33       public   bool  IsReusable 34      { 35           get 36          { 37               return   true ; 38          } 39      } 40  } 41  2.前台页面 *.aspx 代码  1  <% @ Page Language = " C# "  AutoEventWireup = " true "   CodeFile = " Default.aspx.cs "  Inherits = " _Default "   %>  2   3  <! DOCTYPE html PUBLIC  " -//W3C//DTD XHTML 1.0 Transitional//EN "   " http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd " >  4   5  < html xmlns = " http://www.w3.org/1999/xhtml "   >  6  < head runat = " server " >  7       < title > HttpHandler validate users right </ title >  8  </ head >  9  < body > 10       < form id = " form1 "  runat = " server " > 11       < div > 12           < asp:LinkButton ID = " LinkButton1 "  runat = " server "  PostBackUrl = " a.jpeg "  ToolTip = " Click me! "  OnClick = " LinkButton1_Click "  Width = " 149px " > A.jpeg </ asp:LinkButton > 13           & nbsp; 14       </ div > 15       </ form > 16  </ body > 17  </ html > 18 

 3.在Web.Config文件中注册自己的处理程序类配置

1  < system.web > 2       < httpHandlers > 3         < add verb = " * "  path = " *.jpg,*.jpeg "  type = " JpgHandler "   />        4  </ httpHandlers > 5  </ system.web > 6 

在这里我是将处理程序类 JpgHandler.cs 放到 App_Code文件夹下面，如果此类不是放在此类下面，而是以程序集*.dll格式的，则应该将此程序集放到bin目录下面，并且这样配置:

1  < system.web > 2       < httpHandlers > 3         < add verb = " * "  path = " *.jpg,*.jpeg "  type = " JpgHandler,YourDll "   />        4  </ httpHandlers > 5  </ system.web > 6 

  (三). 示例代码下载

           http://www.cnblogs.com/Files/ChengKing/JpgHttpHandler.rar