看下面的处理程序：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace FileExplorer
{
/// <summary>
/// Summary description for HandlerForMyFE
/// </summary>
public class HandlerForMyFE : IHttpHandler,System.Web.SessionState.IRequiresSessionState
{
private HttpContext _context;
private HttpContext Context
{
get
{
return _context;
}
set
{
_context = value;
}
}
public void ProcessRequest(HttpContext context)
{
Context = context;
string filePath = context.Request.QueryString["Downloadpath"];
filePath = context.Server.MapPath(filePath);
if (filePath == null)
{
return;
}
System.IO.StreamReader streamReader = new System.IO.StreamReader(filePath);
System.IO.BinaryReader br = new System.IO.BinaryReader(streamReader.BaseStream);
byte[] bytes = new byte[streamReader.BaseStream.Length];
br.Read(bytes,(int)streamReader.BaseStream.Length);
if (bytes == null)
{
return;
}
streamReader.Close();
br.Close();
string fileName = System.IO.Path.GetFileName(filePath);
string MimeType = GetMimeType(fileName);
string extension = System.IO.Path.GetExtension(filePath);
char[] extension_ar = extension.tocharArray();
string extension_Without_dot = string.Empty;
for (int i = 1; i < extension_ar.Length; i++)
{
extension_Without_dot += extension_ar[i];
}
//if (extension == ".jpg")
//{ // Handle *.jpg and
// WriteFile(bytes,fileName,"image/jpeg jpeg jpg jpe",context.Response);
//}
//else if (extension == ".gif")
//{// Handle *.gif
// WriteFile(bytes,"image/gif gif",context.Response);
//}
if (HttpContext.Current.Session["User_ID"] != null)
{
WriteFile(bytes,MimeType + " " + extension_Without_dot,context.Response);
}
}
private void WriteFile(byte[] content,string fileName,string contentType,HttpResponse response)
{
response.Buffer = true;
response.Clear();
response.ContentType = contentType;
response.AddHeader("content-disposition","attachment; filename=" + fileName);
response.BinaryWrite(content);
response.Flush();
response.End();
}
private string GetMimeType(string fileName)
{
string mimeType = "application/unknown";
string ext = System.IO.Path.GetExtension(fileName).ToLower();
Microsoft.Win32.RegistryKey regKey = Microsoft.Win32.Registry.ClassesRoot.OpenSubKey(ext);
if (regKey != null && regKey.GetValue("Content Type") != null)
mimeType = regKey.GetValue("Content Type").ToString();
return mimeType;
}
public bool IsReusable
{
get
{
return false;
}
}
}
}
我使用这个处理程序下载我的文件而不直接在浏览器中打开它们 – > (使用查询字符串路径)
如何让我的文件恢复？
我在互联网下载管理器中没有这个选项！
解决方法
根据要求,这是答案的“清理”版本：
public static bool DownloadFileMethod(HttpContext httpContext,string filePath,long speed)
{
// Many changes: mostly declare variables near use
// Extracted duplicate references to HttpContext.Response and .Request
// also duplicate reference to .HttpMethod
// Removed try/catch blocks which hid any problems
var response = httpContext.Response;
var request = httpContext.Request;
var method = request.HttpMethod.ToUpper();
if (method != "GET" &&
method != "HEAD")
{
response.StatusCode = 501;
return false;
}
if (!File.Exists(filePath))
{
response.StatusCode = 404;
return false;
}
// Stream implements IDisposable so should be in a using block
using (var myFile = new FileStream(filePath,FileMode.Open,FileAccess.Read,FileShare.ReadWrite))
{
var fileLength = myFile.Length;
if (fileLength > Int32.MaxValue)
{
response.StatusCode = 413;
return false;
}
var lastUpdateTiemStr = File.GetLastWriteTimeUtc(filePath).ToString("r");
var fileName = Path.GetFileName(filePath);
var fileNameUrlEncoded = HttpUtility.UrlEncode(fileName,Encoding.UTF8);
var eTag = fileNameUrlEncoded + lastUpdateTiemStr;
var ifRange = request.Headers["If-Range"];
if (ifRange != null && ifRange.Replace("\"","") != eTag)
{
response.StatusCode = 412;
return false;
}
long startBytes = 0;
// Just guessing,but I bet you want startBytes calculated before
// using to calculate content-length
var rangeHeader = request.Headers["Range"];
if (rangeHeader != null)
{
response.StatusCode = 206;
var range = rangeHeader.Split(new[] {'=','-'});
startBytes = Convert.ToInt64(range[1]);
if (startBytes < 0 || startBytes >= fileLength)
{
// TODO: Find correct status code
response.StatusCode = (int) HttpStatusCode.BadRequest;
response.StatusDescription =
string.Format("Invalid start of range: {0}",startBytes);
return false;
}
}
response.Clear();
response.Buffer = false;
response.AddHeader("Content-MD5",GetMD5Hash(filePath));
response.AddHeader("Accept-Ranges","bytes");
response.AppendHeader("ETag",string.Format("\"{0}\"",eTag));
response.AppendHeader("Last-Modified",lastUpdateTiemStr);
response.ContentType = "application/octet-stream";
response.AddHeader("Content-Disposition","attachment;filename=" +
fileNameUrlEncoded.Replace("+","%20"));
var remaining = fileLength - startBytes;
response.AddHeader("Content-Length",remaining.ToString());
response.AddHeader("Connection","Keep-Alive");
response.ContentEncoding = Encoding.UTF8;
if (startBytes > 0)
{
response.AddHeader("Content-Range",string.Format(" bytes {0}-{1}/{2}",startBytes,fileLength - 1,fileLength));
}
// BinaryReader implements IDisposable so should be in a using block
using (var br = new BinaryReader(myFile))
{
br.BaseStream.Seek(startBytes,SeekOrigin.Begin);
const int packSize = 1024*10; //read in block,every block 10K bytes
var maxCount = (int) Math.Ceiling((remaining + 0.0)/packSize); //download in block
for (var i = 0; i < maxCount && response.IsClientConnected; i++)
{
response.BinaryWrite(br.ReadBytes(packSize));
response.Flush();
// HACK: Unexplained sleep
var sleep = (int) Math.Ceiling(1000.0*packSize/speed); //the number of millisecond
if (sleep > 1) Thread.Sleep(sleep);
}
}
}
return true;
}
