这几天博客都被垃圾评论困扰着，于是就有了一个写一个验证码的想法。这个验证码主要是增加机器识别的难度，当前网上各种流行的验证码中，感觉动网的验证码比较优秀，比较不容易被机器识别。
从动网官网下载了动网.net 1.1版本，用Reflector反编译它的源代码。
请先看动网验证码的截图：
系统自动生成中文、数字、字母的混合字符串，并且自动设置有效的验证码值。上图中的有效验证码值为“mejjh”，而图片全文为“mej的jh”，这样就可以有效地防止被机器识别出验证码了。
我把动网里的验证码代码剥离出来，并作了一些修改。
在动网源代码中，它生成的验证码参数设置是读取Request.QueryString值的，这里我们不再使用这种方式设置验证码，改用xml文件保存设置。
XML配置
xml version="1.0" encoding="utf-8" ?><config> <bgcolor value="LightBlue"/> <bold value="true" /> <forecolor value="Blue" /> <fontfamily value="Arial, Helvetica, sans-serif,宋体" /> <fontsize value="20" /> <height value="70" /> <impurity value="2" /> <italic value="false" /> <width value="180" /> <number value="6" /> <codetext> 我人有的和主产不为这工要在地一上是中经以发了民同国木子123456789abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ]]> codetext>config>
再把xml文件的配置信息映射到一个类上：
XML配置类
/**//// 
/// 验证码配置文件
/// public class ValidateCodeConfig
{
属性#region 属性 private Color bgcolor; /**//// /// 背景色
/// public Color BgColor { get { return bgcolor; } set { bgcolor = value; } } private bool bold; /**//// /// 是否粗体 /// public bool Bold { get { return bold; } set { bold = value; } } private Color forecolor; /**//// /// 颜色 /// public Color ForeColor { get { return forecolor; } set { forecolor = value; } } private string fontFamily; /**//// /// 字体 /// public string FontFamily { get { return fontFamily; } set { fontFamily = value; } } private int fontSize; /**//// /// 字体大小 /// public int FontSize { get { return fontSize; } set { fontSize = value; } } private int height; /**//// /// 高度 /// public int Height { get { return height; } set { if (300 < value) height = 300; else height = value; } } private int impurity; /**//// /// 杂质 /// public int Impurity { get { return impurity; } set { if (30 < value) impurity = 30; else impurity = value; } } private bool italic; /**//// /// 斜体 /// public bool Italic { get { return italic; } set { italic = value; } } private int width; /**//// /// 宽度 /// public int Width { get { return width; } set { if (300 < value) width = 300; else width = value; } } private char[] codetext; /**//// /// 验证码字符 /// public char[] CodeText { get { return codetext; } set { codetext = value; } } private int number; /**//// /// 验证码字数 /// public int Number { get { return number; } set { number = value; } } #endregion /**//// /// 构造函数 /// public ValidateCodeConfig() { LoadXMLOnInit(); } /**//// /// 加载config.xml配置 /// private void LoadXMLOnInit() { XmlDocument doc = new XmlDocument(); doc.Load(HttpContext.Current.Server.MapPath("~/ValidateCode/config.xml")); this.bgcolor = Color.FromName(doc.GetElementsByTagName("bgcolor").Item(0).Attributes["value"].Value); this.bold = Boolean.Parse(doc.GetElementsByTagName("bold").Item(0).Attributes["value"].Value); this.codetext = doc.GetElementsByTagName("codetext").Item(0).InnerText.ToCharArray(); this.fontFamily = doc.GetElementsByTagName("fontfamily").Item(0).Attributes["value"].Value; this.fontSize = int.Parse(doc.GetElementsByTagName("fontsize").Item(0).Attributes["value"].Value); this.forecolor = Color.FromName(doc.GetElementsByTagName("forecolor").Item(0).Attributes["value"].Value); this.height = int.Parse(doc.GetElementsByTagName("height").Item(0).Attributes["value"].Value); this.impurity = int.Parse(doc.GetElementsByTagName("impurity").Item(0).Attributes["value"].Value); this.italic = Boolean.Parse(doc.GetElementsByTagName("italic").Item(0).Attributes["value"].Value); this.width = int.Parse(doc.GetElementsByTagName("width").Item(0).Attributes["value"].Value); this.number = int.Parse(doc.GetElementsByTagName("number").Item(0).Attributes["value"].Value); }}
在绘图方法中调用这个类，并为其设置缓存依赖：
为配置文件设置缓存依赖
/**//// /// 为配置文件设置缓存依赖/// private void LoadConfig(){ if (HttpRuntime.Cache["ValidateCodeConfig"] == null) { config = new ValidateCodeConfig(); CacheDependency dep = new CacheDependency(HttpContext.Current.Server.MapPath("~/ValidateCode/config.xml")); HttpRuntime.Cache.Insert("ValidateCodeConfig", config, dep, DateTime.MaxValue, TimeSpan.Zero); } else { config = (ValidateCodeConfig)HttpRuntime.Cache["ValidateCodeConfig"]; }}
之后，我们就可以开始写生成验证码的主要方法了：
验证码主要方法
/**//// /// 验证码字体样式/// /// private FontStyle GetFontStyle(){ if (config.Bold && config.Italic) { return (FontStyle.Italic | FontStyle.Bold); } if (config.Bold) { return FontStyle.Bold; } if (config.Italic) { return FontStyle.Italic; } return FontStyle.Regular;}private Bitmap GetneralCodeImage(){ bool flag3; Random random = new Random(); Bitmap image = new Bitmap(config.Width, config.Height); Graphics graphics = Graphics.FromImage(image); graphics.Clear(config.BgColor); int length = Directory.GetFiles(Server.MapPath("~/ValidateCode/"), "*.gif").Length; int backgroundfile = random.Next(1, length); Brush brush = new TextureBrush(new Bitmap(Server.MapPath("~/ValidateCode/" + backgroundfile.ToString() + ".gif"))); Rectangle rect = new Rectangle(0, 0, config.Width, config.Height); graphics.FillRectangle(brush, rect); string[] strColorArray = new string[]{ "#666666", "#003300", "#009900", "#330000", "#333300", "#336600", "#660000", "#663300", "#666600", "#FF99FF","#FF33FF", "#CCCCFF", "#CC66FF", "#CC00FF", "#9999FF","#9933FF", "#9900FF", "#FF00FF", "#996633", "#CC3333","#FF3333", "#6633FF", "#0033FF", "#336666", "#CC9900","#6633CC", "#66FF66", "#009999", "#99CC00", "#615379","#E6649E", "#B5B495", "#73CEA7"}; bool istop = random.Next(0, 2) == 0; Pen pen = new Pen(ColorTranslator.FromHtml(strColorArray[random.Next(0, strColorArray.Length)]), 2f); pen.DashStyle = DashStyle.Solid; Point[] randomPointGroup = this.GetRandomPointGroup(istop); for (int i = 0; i < randomPointGroup.Length; i += 2) { graphics.DrawLine(pen, randomPointGroup[i], randomPointGroup[i + 1]); } string input = ""; for (int j = 0; j < config.Number; j++) { input += config.CodeText[random.Next(config.CodeText.Length)].ToString(); } string[] strArray2 = new string[config.Number + 1]; int index = 0;Label_0313: while (index != config.Number) { string str2 = strColorArray[random.Next(0, strColorArray.Length)]; strArray2[index] = str2; index++; for (int n = 0; n < strArray2.Length; n++) { if (strArray2[n] == str2) { goto Label_0313; } if (n == (strArray2.Length - 1)) { strArray2[index] = str2; index++; } } } char[] chArray2 = input.ToCharArray(); int num8 = random.Next(0, config.Number - 1); string str3 = strArray2[num8]; int num9 = random.Next(0, config.Number - 2) + 1; num9 = (num9 == 1) ? 2 : num9; int[] numArray = new int[num9]; numArray[0] = num8; for (int k = 1; k < num9; k++) { int num11 = random.Next(0, config.Number - 1); bool flag2 = false; for (int num12 = 0; num12 < k; num12++) { if (numArray[num12] == num11) { flag2 = true; break; } } if (!flag2) { numArray[k] = num11; } else { k--; } } do { string str4 = strColorArray[random.Next(0, strColorArray.Length)]; flag3 = false; for (int num13 = 0; num13 < strArray2.Length; num13++) { if (str4 == strArray2[num13]) { flag3 = true; break; } } } while (flag3); string strRegexString = ""; string strRegexValidateType = ""; int intValidateType = random.Next(0, 3); bool flag4 = false; while (!flag4) { Match matchChinese; Match matchLetter; Match matchNumber; switch (intValidateType) { case 0: if (!Regex.IsMatch(input, @"[\u4e00-\u9fa5]+")) { goto Label_RandomCodeType; } flag4 = true; strRegexValidateType = "中文字体"; matchChinese = Regex.Match(input, @"[\u4e00-\u9fa5]+", RegexOptions.Multiline | RegexOptions.IgnoreCase); goto Label_ChineseRegexResult; case 1: if (!Regex.IsMatch(input, "[a-zA-Z]+")) { goto Label_RandomCodeType; } flag4 = true; strRegexValidateType = "英文字母"; matchLetter = Regex.Match(input, "[a-zA-Z]+", RegexOptions.Multiline | RegexOptions.IgnoreCase); goto Label_LetterRegexResult; case 2: if (!Regex.IsMatch(input, "[0-9]+")) { goto Label_RandomCodeType; } flag4 = true; strRegexValidateType = "数字"; matchNumber = Regex.Match(input, "[0-9]+", RegexOptions.Multiline | RegexOptions.IgnoreCase); goto Label_NumberRegexResult; case 3: if (Regex.IsMatch(input, @"[^\u4e00-\u9fa5|a-zA-Z|0-9]")) { flag4 = true; strRegexValidateType = "特殊字符"; strRegexString = new Regex(@"[\u4e00-\u9fa5|a-zA-Z|0-9]+").Replace(input, ""); } goto Label_RandomCodeType; default: goto Label_RandomCodeType; } Label_ChineseRegexSuccess: strRegexString = strRegexString + matchChinese.Value; matchChinese = matchChinese.NextMatch(); Label_ChineseRegexResult: if (matchChinese.Success) { goto Label_ChineseRegexSuccess; } goto Label_RandomCodeType; Label_LetterRegexSuccess: strRegexString = strRegexString + matchLetter.Value; matchLetter = matchLetter.NextMatch(); Label_LetterRegexResult: if (matchLetter.Success) { goto Label_LetterRegexSuccess; } goto Label_RandomCodeType; Label_NumberRegexSuccess: strRegexString = strRegexString + matchNumber.Value; matchNumber = matchNumber.NextMatch(); Label_NumberRegexResult: if (matchNumber.Success) { goto Label_NumberRegexSuccess; } Label_RandomCodeType: if (!flag4) { intValidateType = random.Next(0, 3); } } int num16 = 0; for (int m = 0; m < chArray2.Length; m++) { int num21; int num18 = config.FontSize; int num19 = (m == 0) ? 10 : 25; num16 += num19; int num20 = num16; if (istop) { num21 = random.Next(15, config.Height - 35); } else { num21 = random.Next(0, config.Height - 45); } bool flag5 = false; if ((((('.' != chArray2[m]) && ('_' != chArray2[m])) && (('*' != chArray2[m]) && ('`' != chArray2[m]))) && ((('~' != chArray2[m]) && ('.' != chArray2[m])) && ((',' != chArray2[m]) && ('\'' != chArray2[m])))) && ((('-' != chArray2[m]) && ('|' != chArray2[m])) && ('\\' != chArray2[m]))) { char ch1 = chArray2[m]; } graphics.DrawString(chArray2[m].ToString(), new Font(config.FontFamily, flag5 ? ((float)(num18 + 30)) : ((float)num18), flag5 ? FontStyle.Bold : this.GetFontStyle()), new SolidBrush(ColorTranslator.FromHtml(strArray2[m])), (float)num20, (float)num21); } graphics.DrawString("输入图中出现的", new Font("Verdana", 10f, FontStyle.Regular), new SolidBrush(ColorTranslator.FromHtml("#008000")), (2 == intValidateType) ? ((float)18) : ((float)4), istop ? ((float)2) : ((float)(config.Height - 16))); graphics.DrawString(strRegexValidateType, new Font("Verdana", 10f, FontStyle.Bold), new SolidBrush(ColorTranslator.FromHtml("#FF0000")), (2 == intValidateType) ? ((float)126) : ((float)110), istop ? ((float)2) : ((float)(config.Height - 16))); graphics.Dispose(); Response.Cookies.Add(new HttpCookie("ValidateCode", strRegexString.ToLower())); return image;}/**//// /// 杂质/// /// /// private Point[] GetRandomPointGroup(bool istop){ Point[] pointArray = new Point[config.Impurity * 2]; for (int i = 0; i < pointArray.Length; i++) { int num2 = new Random().Next(10000000, 99999999); int x = new Random((num2 / (i + 2)) * (i + 1)).Next(0, config.Width); int y = new Random((num2 / (x + 2)) * (x + 1)).Next(istop ? 16 : 0, istop ? config.Height : (config.Height - 16)); pointArray[i] = new Point(x, y); } return pointArray;}
最后，在Page_Load中调用上面的方法：
private
void
Page_Load(
object
sender, EventArgs e)
{ this.LoadConfig(); base.Response.ContentType = "image/gif"; this.GetneralCodeImage().Save(base.Response.OutputStream, ImageFormat.Gif);}
演示效果如图：
DEMO源码下载：http://www.box.net/shared/g324d08ivy