ASP.NET笔记之 Request 、Response 与Server的使用

<%@ WebHandler Language="C#" Class="image_Test" %>

 using System;
 using System.Web;

 public class image_Test : IHttpHandler {

     public void ProcessRequest(HttpContext context)
     {
         context.Response.ContentType = "image/JPEG";
         //如果直接访问URLreferrer 就是null ，如果嵌入到页面中请求
         //URLreferrer就是页面的地址
         string picPath=HttpContext.Current.Server.MapPath("DSCF0738.JPG");
         using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(picPath)) {
             using (System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(bitmap))
             {
                 //不过还是太脆弱，因为UrlReferrer还是由客户端提交
                 //迅雷破解毫无鸭梨
                 if (context.Request.UrlReferrer == null)
                 {
                     graphic.Clear(System.Drawing.Color.White);
                     graphic.DrawString("禁止直接浏览图片", new System.Drawing.Font("宋体", 15),
                         System.Drawing.Brushes.Red, 0, 0);

                 }
                 //http://127.0.0.1:32581/WebSite_zzl01/vivideo_test/request/Request.aspx

                 else if (context.Request.UrlReferrer.Host != "localhost")
                 {
                     graphic.Clear(System.Drawing.Color.White);
                     graphic.DrawString("图片只允许在博客园内部查看", new System.Drawing.Font("宋体", 15),
                         System.Drawing.Brushes.Red, 0, 0);
                 }
                 //转化成流格式输出
                 bitmap.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);

             }
         }
     }

     public bool IsReusable {
         get {
             return false;
         }
     }

 }

 <%@ WebHandler Language="C#" Class="response" %>

using System;
using System.Web;

public class response : IHttpHandler {

    public void ProcessRequest (HttpContext context) {

        //如果是plain则<br/>无效果
        context.Response.ContentType = "text/html";
        //耗时操作
        for (int i = 0; i < 20; i++)
        {
            System.Threading.Thread.Sleep(500);
            context.Response.Write("第"+i+"步开始执行<br/>");
            //采用Flush,立即发给客户端，效果很明显！
            context.Response.Flush();
        }
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}
 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

public partial class vivideo_test_server_server : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string text=Request["id"];
        if (text == "1") {
            Response.Write("一");
        }
        else if(text=="2"){
            //请求的信息都会传入服务器
            Server.Transfer("DSCF0738.JPG");
        }
        else if (string.IsNullOrEmpty(text))
        {
            Response.Write("空");
        }
        else {
            //不会取到传过来的参数
            Response.Redirect("苹果.jpg");
            //除非自己给它穿过去
            //Response.Redirect("aaa.aspx?id=1");

        }
    }
}