C# C语言中的带宽限制#
我正在开发一个程序,在后台不断发送数据流,我希望允许用户设置上传和下载限制的上限 我读过和alghorhithms,后者似乎符合描述,因为这不是最大化网络带宽的问题,而是尽可能不引人注目 然而,我有点不确定我将如何实现这一点。一种自然的方法是扩展抽象流类,使扩展现有流量变得简单,但这是否不需要额外的线程在同时接收数据时发送数据(漏桶)?任何关于其他实现的提示都将不胜感激 此外,尽管我可以修改程序接收的数据量,但带宽调节在C#级别的效果如何?计算机仍然会接收数据并简单地保存它,从而有效地取消节流效应,还是会等到我要求接收更多数据C# C语言中的带宽限制#,c#,bandwidth,throttling,C#,Bandwidth,Throttling,我正在开发一个程序,在后台不断发送数据流,我希望允许用户设置上传和下载限制的上限 我读过和alghorhithms,后者似乎符合描述,因为这不是最大化网络带宽的问题,而是尽可能不引人注目 然而,我有点不确定我将如何实现这一点。一种自然的方法是扩展抽象流类,使扩展现有流量变得简单,但这是否不需要额外的线程在同时接收数据时发送数据(漏桶)?任何关于其他实现的提示都将不胜感激 此外,尽管我可以修改程序接收的数据量,但带宽调节在C#级别的效果如何?计算机仍然会接收数据并简单地保存它,从而有效地取消节流效
编辑:我对限制传入和传出数据感兴趣,因为我无法控制流的另一端。我提出了arul提到的ThrottledStream类的不同实现。我的版本使用WaitHandle和计时器,间隔为1s:
public ThrottledStream(Stream parentStream, int maxBytesPerSecond=int.MaxValue)
{
MaxBytesPerSecond = maxBytesPerSecond;
parent = parentStream;
processed = 0;
resettimer = new System.Timers.Timer();
resettimer.Interval = 1000;
resettimer.Elapsed += resettimer_Elapsed;
resettimer.Start();
}
protected void Throttle(int bytes)
{
try
{
processed += bytes;
if (processed >= maxBytesPerSecond)
wh.WaitOne();
}
catch
{
}
}
private void resettimer_Elapsed(object sender, ElapsedEventArgs e)
{
processed = 0;
wh.Set();
}
当带宽限制超过时,线程将一直休眠到下一秒开始。无需计算最佳睡眠时间
全面实施:
public class ThrottledStream : Stream
{
#region Properties
private int maxBytesPerSecond;
/// <summary>
/// Number of Bytes that are allowed per second
/// </summary>
public int MaxBytesPerSecond
{
get { return maxBytesPerSecond; }
set
{
if (value < 1)
throw new ArgumentException("MaxBytesPerSecond has to be >0");
maxBytesPerSecond = value;
}
}
#endregion
#region Private Members
private int processed;
System.Timers.Timer resettimer;
AutoResetEvent wh = new AutoResetEvent(true);
private Stream parent;
#endregion
/// <summary>
/// Creates a new Stream with Databandwith cap
/// </summary>
/// <param name="parentStream"></param>
/// <param name="maxBytesPerSecond"></param>
public ThrottledStream(Stream parentStream, int maxBytesPerSecond=int.MaxValue)
{
MaxBytesPerSecond = maxBytesPerSecond;
parent = parentStream;
processed = 0;
resettimer = new System.Timers.Timer();
resettimer.Interval = 1000;
resettimer.Elapsed += resettimer_Elapsed;
resettimer.Start();
}
protected void Throttle(int bytes)
{
try
{
processed += bytes;
if (processed >= maxBytesPerSecond)
wh.WaitOne();
}
catch
{
}
}
private void resettimer_Elapsed(object sender, ElapsedEventArgs e)
{
processed = 0;
wh.Set();
}
#region Stream-Overrides
public override void Close()
{
resettimer.Stop();
resettimer.Close();
base.Close();
}
protected override void Dispose(bool disposing)
{
resettimer.Dispose();
base.Dispose(disposing);
}
public override bool CanRead
{
get { return parent.CanRead; }
}
public override bool CanSeek
{
get { return parent.CanSeek; }
}
public override bool CanWrite
{
get { return parent.CanWrite; }
}
public override void Flush()
{
parent.Flush();
}
public override long Length
{
get { return parent.Length; }
}
public override long Position
{
get
{
return parent.Position;
}
set
{
parent.Position = value;
}
}
public override int Read(byte[] buffer, int offset, int count)
{
Throttle(count);
return parent.Read(buffer, offset, count);
}
public override long Seek(long offset, SeekOrigin origin)
{
return parent.Seek(offset, origin);
}
public override void SetLength(long value)
{
parent.SetLength(value);
}
public override void Write(byte[] buffer, int offset, int count)
{
Throttle(count);
parent.Write(buffer, offset, count);
}
#endregion
}
公共类节流流:流
{
#区域属性
私有整数maxBytesPerSecond;
///
///每秒允许的字节数
///
公共整数MaxBytesPerSecond
{
获取{return maxBytesPerSecond;}
设置
{
如果(值<1)
抛出新ArgumentException(“MaxBytesPerSecond必须大于0”);
maxBytesPerSecond=值;
}
}
#端区
#区域私人成员
已处理的私有int;
System.Timers.Timer resettimer;
AutoResetEvent wh=新的AutoResetEvent(真);
私有流父级;
#端区
///
///使用Databandwith cap创建新流
///
///
///
公共节流流(流父流,int-maxBytesPerSecond=int.MaxValue)
{
MaxBytesPerSecond=MaxBytesPerSecond;
父=父流;
已处理=0;
resettimer=新的System.Timers.Timer();
重置计时器。间隔=1000;
resettimer.Appead+=resettimer\u Appead;
resettimer.Start();
}
受保护的无效限制(整数字节)
{
尝试
{
已处理+=字节;
如果(已处理>=maxBytesPerSecond)
wh.WaitOne();
}
抓住
{
}
}
私有void resettimer_已过(对象发送器,ElapsedEventArgs e)
{
已处理=0;
wh.Set();
}
#区域流覆盖
公共覆盖无效关闭()
{
resettimer.Stop();
resettimer.Close();
base.Close();
}
受保护的覆盖无效处置(布尔处置)
{
resettimer.Dispose();
基地。处置(处置);
}
公共覆盖布尔可读取
{
获取{return parent.CanRead;}
}
公共覆盖布尔搜索
{
获取{return parent.CanSeek;}
}
公共覆盖布尔可写
{
获取{return parent.CanWrite;}
}
公共覆盖无效刷新()
{
parent.Flush();
}
公共覆盖长长度
{
获取{return parent.Length;}
}
公众优先多头仓位
{
得到
{
返回父位置;
}
设置
{
父位置=值;
}
}
公共重写整型读取(字节[]缓冲区、整型偏移量、整型计数)
{
节流阀(计数);
返回parent.Read(缓冲区、偏移量、计数);
}
公共覆盖长寻道(长偏移,参见原始坐标系)
{
返回父搜索(偏移、原点);
}
公共覆盖无效设置长度(长值)
{
父.SetLength(值);
}
公共重写无效写入(字节[]缓冲区、整数偏移量、整数计数)
{
节流阀(计数);
写入(缓冲区、偏移量、计数);
}
#端区
}
基于@0xDEADBEEF的解决方案,我基于Rx调度器创建了以下(可测试)解决方案:
public class ThrottledStream : Stream
{
private readonly Stream parent;
private readonly int maxBytesPerSecond;
private readonly IScheduler scheduler;
private readonly IStopwatch stopwatch;
private long processed;
public ThrottledStream(Stream parent, int maxBytesPerSecond, IScheduler scheduler)
{
this.maxBytesPerSecond = maxBytesPerSecond;
this.parent = parent;
this.scheduler = scheduler;
stopwatch = scheduler.StartStopwatch();
processed = 0;
}
public ThrottledStream(Stream parent, int maxBytesPerSecond)
: this (parent, maxBytesPerSecond, Scheduler.Immediate)
{
}
protected void Throttle(int bytes)
{
processed += bytes;
var targetTime = TimeSpan.FromSeconds((double)processed / maxBytesPerSecond);
var actualTime = stopwatch.Elapsed;
var sleep = targetTime - actualTime;
if (sleep > TimeSpan.Zero)
{
using (var waitHandle = new AutoResetEvent(initialState: false))
{
scheduler.Sleep(sleep).GetAwaiter().OnCompleted(() => waitHandle.Set());
waitHandle.WaitOne();
}
}
}
public override bool CanRead
{
get { return parent.CanRead; }
}
public override bool CanSeek
{
get { return parent.CanSeek; }
}
public override bool CanWrite
{
get { return parent.CanWrite; }
}
public override void Flush()
{
parent.Flush();
}
public override long Length
{
get { return parent.Length; }
}
public override long Position
{
get
{
return parent.Position;
}
set
{
parent.Position = value;
}
}
public override int Read(byte[] buffer, int offset, int count)
{
var read = parent.Read(buffer, offset, count);
Throttle(read);
return read;
}
public override long Seek(long offset, SeekOrigin origin)
{
return parent.Seek(offset, origin);
}
public override void SetLength(long value)
{
parent.SetLength(value);
}
public override void Write(byte[] buffer, int offset, int count)
{
Throttle(count);
parent.Write(buffer, offset, count);
}
}
还有一些只需要几毫秒的测试:
[TestMethod]
public void ShouldThrottleReading()
{
var content = Enumerable
.Range(0, 1024 * 1024)
.Select(_ => (byte)'a')
.ToArray();
var scheduler = new TestScheduler();
var source = new ThrottledStream(new MemoryStream(content), content.Length / 8, scheduler);
var target = new MemoryStream();
var t = source.CopyToAsync(target);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(4).Ticks);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(8).Ticks - 1);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(8).Ticks);
t.Wait(10).Should().BeTrue();
}
[TestMethod]
public void ShouldThrottleWriting()
{
var content = Enumerable
.Range(0, 1024 * 1024)
.Select(_ => (byte)'a')
.ToArray();
var scheduler = new TestScheduler();
var source = new MemoryStream(content);
var target = new ThrottledStream(new MemoryStream(), content.Length / 8, scheduler);
var t = source.CopyToAsync(target);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(4).Ticks);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(8).Ticks - 1);
t.Wait(10).Should().BeFalse();
scheduler.AdvanceTo(TimeSpan.FromSeconds(8).Ticks);
t.Wait(10).Should().BeTrue();
}
如果在计时器计时时不将
processed
设置为0
,而是从中减去maxBytesPerSecond
,则会更精确。在读取中,这会使速度低于限制。例如,您可以从internet下载。缓冲区8Kib,每次读取速度1Kib,限制1Mib/秒。然后每次读取会丢失7Kib,并且以128次读取->每秒16Kib的实际速度读取wh.WaitOne()
。需要修复int read=parent.read(缓冲区、偏移量、计数);节流阀(读取);返回读取代码>有效,thanx!想要使用它的人,需要包括Nuget的反应式扩展