LIOT/Framework/Bowin.Common/FileDownload.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Net;

namespace Bowin.Common
{
    public class FileDownload : IHttpHandler
    {
        public bool IsReusable
        {
            get { return true; }
        }

        public void ProcessRequest(HttpContext context)
        {
            context.Response.Clear();
            string vfilepath = context.Request.QueryString["url"].Trim();

            if (string.IsNullOrEmpty(vfilepath))
            {
                context.Response.StatusCode = 404;
                return;
            }
            var isURL = (vfilepath.ToLower().StartsWith(@"http://") || vfilepath.ToLower().StartsWith(@"https://"));

            string filepath = context.Server.MapPath(isURL ? @"Doc\TempFile\" + Guid.NewGuid() : vfilepath);
            if (isURL)
            {
                WebClient wc = new WebClient();
                wc.DownloadFile(vfilepath, filepath);
            }
            else if (!System.IO.File.Exists(filepath))
            {
                context.Response.StatusCode = 404;
                return;
            }

            string filename = context.Request.QueryString["filename"] ?? System.IO.Path.GetFileName(filepath);

            context.Response.ContentType = "application/octet-stream;charset=GB2312";
            //context.Response.Charset = "GB2312";
            context.Response.AppendHeader("Content-Disposition", "attachment; filename=" + context.Server.UrlEncode(filename));
            
            context.Response.WriteFile(filepath);
            context.Response.Flush();
        }

    }
}