在服务器端的 C# .NET 应用程序中发出蜂鸣声
Beep in C# .NET application on server side
要调试防火墙延迟问题,我需要一个应用程序,它会在检测到 HTTP GET 请求时在服务器端发出蜂鸣声。
此代码(test.ashx):
<%@ WebHandler Language="C#" Class="TestHandler" %>
using System;
using System.Web;
public class TestHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
HttpResponse Response = context.Response;
try
{
Response.Write("Before beep");
Console.Beep();
Response.Write("After beep");
}
catch (Exception ex)
{
Response.Write(ex.Message + "<br />\n" + ex.InnerException.Message);
}
}
public bool IsReusable { get { return false; } }
}
仅在 IIS Express 中调试时发出声音。将 web 应用程序移动到 IIS 后,声音消失了。
试试这个 System.Media.SystemSounds.Beep.Play();
三种简单的发声方法是System.Console.Beep(), System.Media.SoundPlayer, and System.Media.SystemSounds.Beep()。
遗憾的是,这些方法仅适用于桌面应用程序,不适用于服务应用程序。当 ASP.Net 应用程序在 IIS Express(桌面应用程序)下 运行 时,这些声音方法有效。但是,当 ASP.Net 应用程序 运行 在 IIS 服务下时,声音方法不起作用。
System.Console.Beep()最终调用了kernel32.dllBeep()函数。它仅限于桌面应用程序(向下滚动到要求部分)。
System.Media.SoundPlayer 和 System.Media.SystemSounds.Beep() 相同。他们分别调用 kernel32.dll MessageBeep() and the winmm.dll PlaySound() 函数。它们也仅限于桌面应用程序。
在服务中播放声音的一种方法是使用 NAudio。通过 NuGet 很容易安装。
这段代码是我播放声音的唯一方法。它必须在单独的工作线程上播放,并且需要暂停工作线程的执行以让.wav 文件完成播放。
using System;
using System.Diagnostics;
using System.Threading;
using NAudio.Dsp;
using NAudio.Wave;
...
protected void Button1_Click(object sender, EventArgs e)
{
var waveFilename = @"c:\Windows\Media\tada.wav";
/* Trying to play the .wav file on the main thread
doesn't seem to work. */
ThreadPool.QueueUserWorkItem(
(state) =>
{
using (var audioPlayback = new AudioPlayback())
{
audioPlayback.Load(waveFilename);
audioPlayback.Play(); // Asynchronous.
/* Need to sleep for the approximate length of .wav file,
otherwise no sound is produced because of the
asynchronous Play() call. */
Thread.Sleep(2000);
}
});
}
以下是从 NAudio 的 NAudioWPFDemo 项目中获取的支持代码:
public class MaxSampleEventArgs : EventArgs
{
[DebuggerStepThrough]
public MaxSampleEventArgs(float minValue, float maxValue)
{
this.MaxSample = maxValue;
this.MinSample = minValue;
}
public float MaxSample { get; private set; }
public float MinSample { get; private set; }
}
public class FftEventArgs : EventArgs
{
[DebuggerStepThrough]
public FftEventArgs(Complex[] result)
{
this.Result = result;
}
public Complex[] Result { get; private set; }
}
public class SampleAggregator : ISampleProvider
{
// volume
public event EventHandler<MaxSampleEventArgs> MaximumCalculated;
private float maxValue;
private float minValue;
public int NotificationCount { get; set; }
int count;
// FFT
public event EventHandler<FftEventArgs> FftCalculated;
public bool PerformFFT { get; set; }
private readonly Complex[] fftBuffer;
private readonly FftEventArgs fftArgs;
private int fftPos;
private readonly int fftLength;
private int m;
private readonly ISampleProvider source;
private readonly int channels;
public SampleAggregator(ISampleProvider source, int fftLength = 1024)
{
channels = source.WaveFormat.Channels;
if (!IsPowerOfTwo(fftLength))
throw new ArgumentException("FFT Length must be a power of two");
this.m = (int) Math.Log(fftLength, 2.0);
this.fftLength = fftLength;
this.fftBuffer = new Complex[fftLength];
this.fftArgs = new FftEventArgs(fftBuffer);
this.source = source;
}
private bool IsPowerOfTwo(int x)
{
return (x & (x - 1)) == 0;
}
public void Reset()
{
count = 0;
maxValue = minValue = 0;
}
private void Add(float value)
{
if (PerformFFT && FftCalculated != null)
{
fftBuffer[fftPos].X = (float) (value * FastFourierTransform.HammingWindow(fftPos, fftLength));
fftBuffer[fftPos].Y = 0;
fftPos++;
if (fftPos >= fftBuffer.Length)
{
fftPos = 0;
// 1024 = 2^10
FastFourierTransform.FFT(true, m, fftBuffer);
FftCalculated(this, fftArgs);
}
}
maxValue = Math.Max(maxValue, value);
minValue = Math.Min(minValue, value);
count++;
if (count >= NotificationCount && NotificationCount > 0)
{
if (MaximumCalculated != null)
MaximumCalculated(this, new MaxSampleEventArgs(minValue, maxValue));
Reset();
}
}
public WaveFormat WaveFormat { get { return source.WaveFormat; } }
public int Read(float[] buffer, int offset, int count)
{
var samplesRead = source.Read(buffer, offset, count);
for (int n = 0; n < samplesRead; n += channels)
Add(buffer[n + offset]);
return samplesRead;
}
}
public class AudioPlayback : IDisposable
{
private IWavePlayer _playbackDevice;
private WaveStream _fileStream;
public void Load(string fileName)
{
Stop();
CloseFile();
EnsureDeviceCreated();
OpenFile(fileName);
}
private void CloseFile()
{
if (_fileStream != null)
{
_fileStream.Dispose();
_fileStream = null;
}
}
private void OpenFile(string fileName)
{
try
{
var inputStream = new AudioFileReader(fileName);
_fileStream = inputStream;
var aggregator = new SampleAggregator(inputStream);
aggregator.NotificationCount = inputStream.WaveFormat.SampleRate / 100;
aggregator.PerformFFT = true;
_playbackDevice.Init(aggregator);
}
catch
{
CloseFile();
throw;
}
}
private void EnsureDeviceCreated()
{
if (_playbackDevice == null)
CreateDevice();
}
private void CreateDevice()
{
_playbackDevice = new WaveOut { DesiredLatency = 200 };
}
public void Play()
{
if (_playbackDevice != null && _fileStream != null && _playbackDevice.PlaybackState != PlaybackState.Playing)
_playbackDevice.Play();
}
public void Pause()
{
if (_playbackDevice != null)
_playbackDevice.Pause();
}
public void Stop()
{
if (_playbackDevice != null)
_playbackDevice.Stop();
if (_fileStream != null)
_fileStream.Position = 0;
}
public void Dispose()
{
Stop();
CloseFile();
if (_playbackDevice != null)
_playbackDevice.Dispose();
}
}
要调试防火墙延迟问题,我需要一个应用程序,它会在检测到 HTTP GET 请求时在服务器端发出蜂鸣声。
此代码(test.ashx):
<%@ WebHandler Language="C#" Class="TestHandler" %>
using System;
using System.Web;
public class TestHandler : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
HttpResponse Response = context.Response;
try
{
Response.Write("Before beep");
Console.Beep();
Response.Write("After beep");
}
catch (Exception ex)
{
Response.Write(ex.Message + "<br />\n" + ex.InnerException.Message);
}
}
public bool IsReusable { get { return false; } }
}
仅在 IIS Express 中调试时发出声音。将 web 应用程序移动到 IIS 后,声音消失了。
试试这个 System.Media.SystemSounds.Beep.Play();
三种简单的发声方法是System.Console.Beep(), System.Media.SoundPlayer, and System.Media.SystemSounds.Beep()。
遗憾的是,这些方法仅适用于桌面应用程序,不适用于服务应用程序。当 ASP.Net 应用程序在 IIS Express(桌面应用程序)下 运行 时,这些声音方法有效。但是,当 ASP.Net 应用程序 运行 在 IIS 服务下时,声音方法不起作用。
System.Console.Beep()最终调用了kernel32.dllBeep()函数。它仅限于桌面应用程序(向下滚动到要求部分)。
System.Media.SoundPlayer 和 System.Media.SystemSounds.Beep() 相同。他们分别调用 kernel32.dll MessageBeep() and the winmm.dll PlaySound() 函数。它们也仅限于桌面应用程序。
在服务中播放声音的一种方法是使用 NAudio。通过 NuGet 很容易安装。
这段代码是我播放声音的唯一方法。它必须在单独的工作线程上播放,并且需要暂停工作线程的执行以让.wav 文件完成播放。
using System;
using System.Diagnostics;
using System.Threading;
using NAudio.Dsp;
using NAudio.Wave;
...
protected void Button1_Click(object sender, EventArgs e)
{
var waveFilename = @"c:\Windows\Media\tada.wav";
/* Trying to play the .wav file on the main thread
doesn't seem to work. */
ThreadPool.QueueUserWorkItem(
(state) =>
{
using (var audioPlayback = new AudioPlayback())
{
audioPlayback.Load(waveFilename);
audioPlayback.Play(); // Asynchronous.
/* Need to sleep for the approximate length of .wav file,
otherwise no sound is produced because of the
asynchronous Play() call. */
Thread.Sleep(2000);
}
});
}
以下是从 NAudio 的 NAudioWPFDemo 项目中获取的支持代码:
public class MaxSampleEventArgs : EventArgs
{
[DebuggerStepThrough]
public MaxSampleEventArgs(float minValue, float maxValue)
{
this.MaxSample = maxValue;
this.MinSample = minValue;
}
public float MaxSample { get; private set; }
public float MinSample { get; private set; }
}
public class FftEventArgs : EventArgs
{
[DebuggerStepThrough]
public FftEventArgs(Complex[] result)
{
this.Result = result;
}
public Complex[] Result { get; private set; }
}
public class SampleAggregator : ISampleProvider
{
// volume
public event EventHandler<MaxSampleEventArgs> MaximumCalculated;
private float maxValue;
private float minValue;
public int NotificationCount { get; set; }
int count;
// FFT
public event EventHandler<FftEventArgs> FftCalculated;
public bool PerformFFT { get; set; }
private readonly Complex[] fftBuffer;
private readonly FftEventArgs fftArgs;
private int fftPos;
private readonly int fftLength;
private int m;
private readonly ISampleProvider source;
private readonly int channels;
public SampleAggregator(ISampleProvider source, int fftLength = 1024)
{
channels = source.WaveFormat.Channels;
if (!IsPowerOfTwo(fftLength))
throw new ArgumentException("FFT Length must be a power of two");
this.m = (int) Math.Log(fftLength, 2.0);
this.fftLength = fftLength;
this.fftBuffer = new Complex[fftLength];
this.fftArgs = new FftEventArgs(fftBuffer);
this.source = source;
}
private bool IsPowerOfTwo(int x)
{
return (x & (x - 1)) == 0;
}
public void Reset()
{
count = 0;
maxValue = minValue = 0;
}
private void Add(float value)
{
if (PerformFFT && FftCalculated != null)
{
fftBuffer[fftPos].X = (float) (value * FastFourierTransform.HammingWindow(fftPos, fftLength));
fftBuffer[fftPos].Y = 0;
fftPos++;
if (fftPos >= fftBuffer.Length)
{
fftPos = 0;
// 1024 = 2^10
FastFourierTransform.FFT(true, m, fftBuffer);
FftCalculated(this, fftArgs);
}
}
maxValue = Math.Max(maxValue, value);
minValue = Math.Min(minValue, value);
count++;
if (count >= NotificationCount && NotificationCount > 0)
{
if (MaximumCalculated != null)
MaximumCalculated(this, new MaxSampleEventArgs(minValue, maxValue));
Reset();
}
}
public WaveFormat WaveFormat { get { return source.WaveFormat; } }
public int Read(float[] buffer, int offset, int count)
{
var samplesRead = source.Read(buffer, offset, count);
for (int n = 0; n < samplesRead; n += channels)
Add(buffer[n + offset]);
return samplesRead;
}
}
public class AudioPlayback : IDisposable
{
private IWavePlayer _playbackDevice;
private WaveStream _fileStream;
public void Load(string fileName)
{
Stop();
CloseFile();
EnsureDeviceCreated();
OpenFile(fileName);
}
private void CloseFile()
{
if (_fileStream != null)
{
_fileStream.Dispose();
_fileStream = null;
}
}
private void OpenFile(string fileName)
{
try
{
var inputStream = new AudioFileReader(fileName);
_fileStream = inputStream;
var aggregator = new SampleAggregator(inputStream);
aggregator.NotificationCount = inputStream.WaveFormat.SampleRate / 100;
aggregator.PerformFFT = true;
_playbackDevice.Init(aggregator);
}
catch
{
CloseFile();
throw;
}
}
private void EnsureDeviceCreated()
{
if (_playbackDevice == null)
CreateDevice();
}
private void CreateDevice()
{
_playbackDevice = new WaveOut { DesiredLatency = 200 };
}
public void Play()
{
if (_playbackDevice != null && _fileStream != null && _playbackDevice.PlaybackState != PlaybackState.Playing)
_playbackDevice.Play();
}
public void Pause()
{
if (_playbackDevice != null)
_playbackDevice.Pause();
}
public void Stop()
{
if (_playbackDevice != null)
_playbackDevice.Stop();
if (_fileStream != null)
_fileStream.Position = 0;
}
public void Dispose()
{
Stop();
CloseFile();
if (_playbackDevice != null)
_playbackDevice.Dispose();
}
}