如何在ASP.Net中实现自定义音频Capcha
我们使用C＃.Net创建了一个Custom Capcha生成器。 现在我们要求升级我们的Capcha以包含音频function（Listen Capcha）。 我们的主要限制是我们不能使用任何第三方组件（Dlls）
请指导我实现这样的function。
提前致谢。
我过去做过这样的事情。 需要将背噪（乐器音乐）与连接的字母/字符合并。 另外，我们使用不同的声音制作录音。 所有这些都增加了“智能代码”的复杂性，能够从语音中提取validation码文本。 由于显而易见的原因，我还将最终的WAVE转换为MP3（使用lame_enc.dll）。 解释你如何做到这一点并不容易，所以我包含了作业所需的第一个草稿版本，因为它使用了第三方DLL而省略了MP3代码。
using System; using System.Collections.Generic; using System.Drawing; using System.Drawing.Drawing2D; using System.Drawing.Imaging; using System.Drawing.Text; using System.IO; using System.Reflection; namespace suryakiran { internal static partial class Extensions { internal static byte[] AudioCaptcha(this string text) { String en = "abcdefghijkoprstvx0123456789", Location = string.Concat(System.Web.HttpContext.Current.Request.ServerVariables["APPL_PHYSICAL_PATH"].ToString(), @"\bin\wav\"); Int32 dataLength = 0, length = 0, sampleRate = 0, plus = 37500, p = 0; Int16 bitsPerSample = 0, channels = 0; Byte[] music, wav; Random r = new Random(); p = r.Next(1, 4000000); p += (p % 150) + 44; Byte[] rb = new Byte[9 * plus]; // read music using (FileStream fs = new FileStream(String.Format(Location + @"z{0}.wav", (r.Next() % 12) + 1), FileMode.Open, FileAccess.Read, FileShare.ReadWrite)) { wav = new Byte[44]; fs.Read(wav, 0, 44); fs.Position = (long)p; fs.Read(rb, 0, rb.Length); } // make music using (MemoryStream ms = new MemoryStream()) { channels = BitConverter.ToInt16(wav, 22); sampleRate = BitConverter.ToInt32(wav, 24); bitsPerSample = BitConverter.ToInt16(wav, 34); length = rb.Length; dataLength = rb.Length; ms.Write(new Byte[44], 0, 44); ms.Write(rb, 0, rb.Length); ms.Position = 0; using (BinaryWriter bw = new BinaryWriter(ms)) { bw.Write(new char[4] { 'R', 'I', 'F', 'F' }); bw.Write(length); bw.Write(new char[8] { 'W', 'A', 'V', 'E', 'f', 'm', 't', ' ' }); bw.Write((Int32)16); bw.Write((Int16)1); bw.Write(channels); bw.Write(sampleRate); bw.Write((Int32)(sampleRate * ((bitsPerSample * channels) / 8))); bw.Write((Int16)((bitsPerSample * channels) / 8)); bw.Write(bitsPerSample); bw.Write(new char[4] { 'd', 'a', 't', 'a' }); bw.Write(dataLength); music = ms.ToArray(); p = 0; } } using (MemoryStream final = new MemoryStream()) { final.Write(music, 0, 44); // make voice using (MemoryStream msvoice = new MemoryStream()) { msvoice.Write(new Byte[plus / 2], 0, plus / 2); length += plus; dataLength += plus / 2; p += plus / 2; for (var i = 0; i < text.Length; i++) { String fn = String.Format(Location + @"{0}\{1}.wav", (r.Next() % 3), en.Substring(en.IndexOf(text.Substring(i, 1)), 1)).Replace("?", "qm"); wav = File.ReadAllBytes(fn); Int32 size = BitConverter.ToInt32(wav, 4); { msvoice.Write(new Byte[plus / 2], 0, plus / 2); length += plus; dataLength += plus / 2; p += plus / 2; } msvoice.Write(wav, 44, wav.Length - 44); length += size; dataLength += size - 36; } msvoice.Position = 0; MemoryStream msmusic = new MemoryStream(); msmusic.Write(music, 0, music.Length); msmusic.Position = 44; //merge; while (final.Length < msmusic.Length) final.WriteByte((byte)(msvoice.ReadByte() - msmusic.ReadByte())); return final.ToArray(); } } } internal static Byte[] VisualCaptcha(this String source) { try { Random r = new Random(); Int32 w = 250, h = 75; String family = "Arial Rounded MT Bold"; using (var bmp = new Bitmap(w, h, PixelFormat.Format32bppArgb)) { Int32 m = 0, nm = 0; Color tc; using (var g = Graphics.FromImage(bmp)) { g.TextRenderingHint = TextRenderingHint.AntiAlias; g.SmoothingMode = SmoothingMode.HighQuality; g.Clear(Color.White); SizeF size; m = r.Next() % 9 + 1; nm = r.Next() % 3; tc = Color.FromArgb(255, 255, 255); size = g.MeasureString(source, new Font(family, h * 1.2f, FontStyle.Bold), new SizeF(w * 1F, h * 1F)); using (var brush = new LinearGradientBrush(new Rectangle(0, 0, w, h), Color.Black, Color.Black, 45, false)) { ColorBlend blend = new ColorBlend(6); for (var i = 0; i < 6; i++) { blend.Positions[i] = i * (1 / 5F); blend.Colors[i] = r.RandomColor(255, 64, 128); } brush.InterpolationColors = blend; for (int wave = 0; wave < 2; wave++) { Int32 min = (15 + wave * 20); PointF[] pt = new PointF[] { new PointF(16f, (float)r.Next(min, min + 10)), new PointF(240f, (float)r.Next(min + 10, min + 20)) }; List PointList = new List (); float curDist = 0, distance = 0; for (int i = 0; i < pt.Length - 1; i++) { PointF ptA = pt[i], ptB = pt[i + 1]; float deltaX = ptB.X - ptA.X, deltaY = ptB.Y - ptA.Y; curDist = 0; distance = (float)Math.Sqrt(Math.Pow(deltaX, 2) + Math.Pow(deltaY, 2)); while (curDist < distance) { curDist++; float offsetX = (float)((double)curDist / (double)distance * (double)deltaX); float offsetY = (float)((double)curDist / (double)distance * (double)deltaY); PointList.Add(new PointF(ptA.X + offsetX, ptA.Y + offsetY)); } } for (int i = 0; i < PointList.Count - 24; i = i + 24) { float x1 = PointList[i].X, y1 = PointList[i].Y, x2 = PointList[i + 24].X, y2 = PointList[i + 24].Y; float angle = (float)((Math.Atan2(y2 - y1, x2 - x1) * 180 / 3.14159265)); g.TranslateTransform(x1, y1); g.RotateTransform(angle); Int32 pm = r.Next() % 2 + 1; Point[] p1 = new Point[] { new Point(0, 0), new Point(3, -3 * pm), new Point(6, -4 * pm), new Point(9, -3 * pm), new Point(12, 0), new Point(15, 3 * pm), new Point(18, 4 * pm), new Point(21, 3 * pm), new Point(24, 0) }; using (var path = new GraphicsPath()) g.DrawLines(new Pen(brush, 2f), p1); g.RotateTransform(-angle); g.TranslateTransform(-x1, -y1); } } using (var path = new GraphicsPath()) { PointF[] points = new PointF[] { }; if (m == 1 || m == 2 || m == 3) // star trek inverse { path.AddString(source, new FontFamily(family), 1, h * 0.75F, new PointF((w - size.Width) / 2F, (h * 0.9F - size.Height) / 2F), StringFormat.GenericTypographic); points = new PointF[] { new PointF(0, 0), new PointF(w, 0), new PointF(w * 0.2F, h), new PointF(w * 0.8F, h) }; } else if (m == 4 || m == 5) // star trek { path.AddString(source, new FontFamily(family), 1, h * 0.75F, new PointF((w - size.Width) / 2F, (h * 1.2F - size.Height) / 2F + 2F), StringFormat.GenericTypographic); points = new PointF[] { new PointF(w * 0.2F, 0), new PointF(w * 0.8F, 0), new PointF(0, h), new PointF(w, h) }; } else if (m == 6 || m == 7) // grow from left { path.AddString(source, new FontFamily(family), 1, h * 0.75F, new PointF((w * 1.15F - size.Width) / 2F, (h - size.Height) / 2F), StringFormat.GenericTypographic); points = new PointF[] { new PointF(0, h * 0.25F), new PointF(w, 0), new PointF(0, h * 0.75F), new PointF(w, h) }; } else if (m == 8 || m == 9) // grow from right { path.AddString(source, new FontFamily(family), 1, h * 0.75F, new PointF((w * 0.85F - size.Width) / 2F, (h - size.Height) / 2F), StringFormat.GenericTypographic); points = new PointF[] { new PointF(w * 0.1F, 0), new PointF(w * 0.9F, h * 0.25F), new PointF(w * 0.1F, h), new PointF(w * 0.9F, h * 0.75F) }; } path.Warp(points, new RectangleF(0, 0, w, h)); g.FillPath(Brushes.White, path); g.DrawPath(new Pen(brush, 2F), path); } } } using (var thumb = new Bitmap(128, 40, PixelFormat.Format32bppArgb)) { using (var g = Graphics.FromImage(thumb)) { g.CompositingQuality = CompositingQuality.HighQuality; g.SmoothingMode = SmoothingMode.HighQuality; g.InterpolationMode = InterpolationMode.HighQualityBicubic; Rectangle tr = new Rectangle(0, 0, thumb.Width, thumb.Height); g.DrawImage(bmp, tr); g.DrawRectangle(new Pen(Brushes.White), new Rectangle(0, 0, 127, 39)); } using (var ms = new MemoryStream()) { ((Image)thumb).Save(ms, ImageFormat.Png); return ms.ToArray(); } } } } catch { return null; } } private static Color RandomColor(this Random rnd, Int32 alpha, Int32 min, Int32 max) { return Color.FromArgb(alpha, rnd.Next(min, max), rnd.Next(min, max), rnd.Next(min, max)); } } }
对于视觉和音频生成，代码独立于validation码生成（源文本）。 WAVE格式的每个字母音频文件大约30KB，但每个音乐文件至少为8MB，为我提供了广泛的随机起始位置范围（避免 - 经常重复的模式）。 您可以将代码编译为dll或将其（修改）放在代码隐藏文件中。
这个想法很简单。
对于您拥有的每个角色，您将其录制为音频，然后您以与显示角色相同的顺序简单播放录制的音频。
所以对于角色A，你拼写它并将其记录在一个wav文件中，当你听到它说“alpha”清晰而响亮。
阅读此答案以了解如何播放它们： 如何在Web浏览器中播放音频和video文件？
声音编辑背后的代码
如果您想将音频连接到一个文件，您可以选择一个包含所有现成function的音频库。
我知道其中最好的是http://www.un4seen.com/上的低音音频库
当然，因为你只需要添加两个音频，你可以直接使用windows媒体库 ，查看它的SDK http://msdn.microsoft.com/en-us/library/windows/desktop/dd757738(v = vs.85）的.aspx
Windows媒体已准备好使用Windows内部的function，这些function可以通过音频等媒体来实现。
我将跳过很多validation码安全性和生成细节，以支持展示我的提议。
我在服务器端使用了语音合成器。
在Web应用程序项目中，添加对System.Speech.dll的引用
我创建了两个页面：
Start.aspx – >用户将看到的页面。 有了这两个要素：
后面的代码应该像这样（简化）
public partial class Start : System.Web.UI.Page { protected void Page_Load(object sender, EventArgs e) { // You generate your captcha somehow string captchaString = "EFG 6 7"; // Let's store the captcha in a place so that our wave generator can find it. Session.Add("captcha", captchaString); // Display the captcha in the page (this should actually be a blurry non-human readable image) lblCaptchaText.InnerText = captchaString; } }
AudioPlayer.aspx – >为用户生成波形输出的页面。 HTML方面没有任何内容。
public partial class AudioPlayer : System.Web.UI.Page { protected override void OnPreRender(EventArgs e) { Response.ContentType = "audio/wav"; MemoryStream mstream = GetAudio(Session["captcha"] as string); mstream.Position = 0; mstream.CopyTo(Response.OutputStream); Response.End(); } public static MemoryStream GetAudio(string input) { MemoryStream mem = new MemoryStream(); Thread t = new Thread(new ThreadStart(() => { SpeechSynthesizer synth = new SpeechSynthesizer(); synth.Rate = -5; synth.SetOutputToWaveStream(mem); synth.Speak(input); })); t.Start(); t.Join(); return mem; } }
编译您的网站并运行Start.aspx，您将听到您的validation码。
使用Microsoft Speech SDK，性能，资源管理，可扩展性等时需要考虑很多事情。好消息是，他们的语音识别引擎和语音合成器的服务器“风味”称为Microsoft Speech Server。
RECAPTHA默认有这个，所以你为什么要重新发明轮子呢？