请教C#做限速下载

yuquan1987 2011-06-05 01:08:30
我现在想做一个简单的下载工具,就是制定一个下载的url地址。然后自己在程序中输入50k每秒。那么我这个程序的下载速度就被限制到50k每秒了。【不管是1个线程下载还是多个线程下载,总之就是所有的线程下载和就是 50k每秒】。这个如何实现呢?
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xiaoqiu1234 2011-06-18
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ycproc 2011-06-18
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不管你怎么急速

也需要客户端的带宽 网速 的支持
yuquan1987 2011-06-17
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先谢谢各位捧场,我用的是10个线程下载。按照楼上说的 我勉强弄出来了。现在有个新的问题是,我设置30k每秒,总是有几个线程会操作超时。也就是10个线程中能正常下载的只有5-6个。最终下载下来的也不能用。然后我设置成100k每秒就没问题了。不知道这是什么回事?
wangzhangxiaoyu 2011-06-16
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[Quote=引用 3 楼 porschev 的回复:]
C# code

/// <summary>
/// 输出硬盘文件,提供下载
/// </summary>
/// <param name="context">HttpContext对象</param>
/// <param name="_fullPath">要下载的文件的完整路径</param>
/// <param name="_speed">每秒允许下载的字节数</param>
……
[/Quote]

这种方法会导致当前线程阻塞吧?访问其他页面会出现问题.
wangxiao2008 2011-06-05
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这个下载速度能控制的好吗?
得考虑服务器的负载吧
porschev 2011-06-05
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/// <summary>
/// 输出硬盘文件,提供下载
/// </summary>
/// <param name="context">HttpContext对象</param>
/// <param name="_fullPath">要下载的文件的完整路径</param>
/// <param name="_speed">每秒允许下载的字节数</param>
/// <returns>是否成功</returns>
public static bool ResponseFile(HttpContext context, string _fullPath, long _speed) {
HttpRequest _Request = context.Request;
HttpResponse _Response = context.Response;
string strFileName = new FileInfo(_fullPath).Name;
try {
FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
BinaryReader br = new BinaryReader(myFile);
try {
_Response.AddHeader("Accept-Ranges", "bytes");
_Response.Buffer = false;
long fileLength = myFile.Length;
long startBytes = 0;

int pack = 10240; //10K bytes 进行拆包,每包大小
int sleep = (int)Math.Floor(1000 * pack / _speed) + 1; //pack/_speed 每个包发送速度/秒 总的意思:发包频率
if (_Request.Headers["Range"] != null) {
_Response.StatusCode = 206;
string[] range = _Request.Headers["Range"].Split(new char[] { '=', '-' });
startBytes = Convert.ToInt64(range[1]);
}
_Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
if (startBytes != 0) {
_Response.AddHeader("Content-Range", string.Format(" bytes {0}-{1}/{2}", startBytes, fileLength - 1, fileLength));
}
_Response.AddHeader("Connection", "Keep-Alive");
_Response.ContentType = "application/octet-stream";
_Response.AddHeader("Content-Disposition", "attachment;filename=" + HttpUtility.UrlEncode(strFileName, System.Text.Encoding.UTF8));
br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
int maxCount = (int)Math.Floor((fileLength - startBytes) / pack) + 1;
for (int i = 0; i < maxCount; i++) {
if (_Response.IsClientConnected) {
_Response.BinaryWrite(br.ReadBytes(pack));
_Response.Flush();
System.Threading.Thread.Sleep(sleep); //线程休息sleep毫秒后继续
} else {
i = maxCount;
}
}
} catch {
return false;
} finally {
br.Close();
myFile.Close();
}
} catch {
return false;
}
return true;
}

cjh200102 2011-06-05
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网上应该不少
kid_wang 2011-06-05
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从网上来的,楼主也可以google一下啊

protected void DoDownLoad(long lngSpeed)
{
Page.Response.Clear();
bool success = ResponseFile(Page.Request, Page.Response, "下载时显示的名称.rar", "E:\\WWWROOT\\files\\www.linjunjie.net.rar", lngSpeed);
if (!success)
{
Response.Write("下载文件出错!");
}
else
{
Response.Write("下载文件成功!");
}
Page.Response.End();
}

public static bool ResponseFile(HttpRequest _Request, HttpResponse _Response, string _fileName, string _fullPath, long _speed)
{
try
{
FileStream myFile = new FileStream(_fullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
BinaryReader br = new BinaryReader(myFile);
try
{
_Response.AddHeader("Accept-Ranges", "bytes");
_Response.Buffer = false;
long fileLength = myFile.Length;
long startBytes = 0;
double pack = 1024;
int sleep = (int)Math.Floor(1000 * pack / _speed) + 1;
if (_Request.Headers["Range"] != null)
{
_Response.StatusCode = 206;
string[] range = _Request.Headers["Range"].Split(new char[] { '=', '-' });
startBytes = Convert.ToInt64(range[1]);
}
_Response.AddHeader("Content-Length", (fileLength - startBytes).ToString());
_Response.AddHeader("Connection", "Keep-Alive");
_Response.ContentType = "application/octet-stream";
_Response.AddHeader("Content-Disposition", "attachment; filename=" + HttpUtility.UrlEncode(_fileName, System.Text.Encoding.UTF8)); br.BaseStream.Seek(startBytes, SeekOrigin.Begin);
int maxCount = (int)Math.Floor((fileLength - startBytes) / pack) + 1;
for (int i = 0; i < maxCount; i++)
{
if (_Response.IsClientConnected)
{
_Response.BinaryWrite(br.ReadBytes(int.Parse(pack.ToString())));
Thread.Sleep(sleep);
}
else
{
i = maxCount;
}
}
}
catch (Exception e4)
{
System.Web.HttpContext.Current.Response.Write(e4.Message);
return false;
}
finally
{
br.Close();
myFile.Close();
}
}
catch (Exception e3)
{
System.Web.HttpContext.Current.Response.Write(e3.Message);
return false;
}
return true;
}

protected void Button1_Click(object sender, EventArgs e)
{
DoDownLoad(5 * 1024);
}
protected void Button2_Click(object sender, EventArgs e)
{
DoDownLoad(50 * 1024);
}
chengjia2284 2011-06-05
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[Quote=引用 1 楼 kid_wang 的回复:]
从网上来的,楼主也可以google一下啊

C# code

protected void DoDownLoad(long lngSpeed)
{
Page.Response.Clear();
bool success = ResponseFile(Page.Request, Page.Response, "下载时显示的名称.rar", "E:\\WWWROOT\\files\\ww……
[/Quote]

+1不错

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