12306奇葩验证码引发思考之C#实现验证码程序
近日铁路订票网“12306”又出现多道另类考题,竟要订票者在8个图案中“点击图中所有美男子”、“请点击下图中所有的非智能眼镜”、“请点击下图中所有的博斯普鲁斯海峡”,网友吐槽:比高考题还难,到底是什么样子的,先跟大家分享一下几个例子:
哈哈,是有点奇葩的验证码,怪不得有人会说“妈妈我已经找不到回家”,这让分秒必争的春运网上抢票者瞬间傻眼,九成网友已经被打败……
正巧小编最近也在研究验证码,参考了许多网上案例,整理了一篇文章特分享给大家。
验证码的一般编写思路为:
1.定义验证码字符长度;
2.根据长度随机生成验证码字符串;
3.将验证码字符串转换成图片形式,并在图片中生成随机噪声点和声线(对验证码进行模糊识别处理);
4.显示结果。
/// /// 生成随机验证码 /// /// 验证码长度 /// public string createidentifyingcode(int codelen) { if (codelen < 1) return string.empty; int num; string checkcode = string.empty; random random = new random(); for (int index = 0; index < codelen; index++) { num = random.next(); if (num % 2 == 0) checkcode += (char)('0' + (char)(num % 10)); else checkcode += (char)('a' + (char)(num % 26)); } return checkcode; } ------------------------------------------------------------------------------------------------- /// /// 生成验证码图片 /// /// /// private void createcheckcodeimage(string checkcode) { if (checkcode == null || checkcode.trim() == string.empty) return; //创建图片大小 system.drawing.bitmap image = new system.drawing.bitmap((int)math.ceiling(checkcode.length*12.5),22); //创建画板 graphics graphic = graphics.fromimage(image); try { random random = new random(); graphic.clear(color.white); int x1 = 0, y1 = 0, x2 = 0, y2 = 0; //画图片背景噪声线 for (int index = 0; index < 25; index++) { x1 = random.next(image.width); y1 = random.next(image.height); x2 = random.next(image.width); y2 = random.next(image.height); graphic.drawline(new pen(color.silver),x1,y1,x2,y2); } font font = new system.drawing.font("helvetica", 12, (fontstyle.bold |fontstyle.italic)); lineargradientbrush brush = new lineargradientbrush(new rectangle(0, 0, image.width, image.height),color.blue,color.darkblue,1.2f,true); graphic.drawstring(checkcode,font,brush,2,2); int x = 0; int y = 0; // 画图片的前景噪声点 for (int index = 0; index < 100; index++) { x = random.next(image.width); y = random.next(image.height); image.setpixel(x,y,color.fromargb(random.next())); } //画图片的边框线 graphic.drawrectangle(new pen(color.silver), 0, 0, image.width - 1, image.height - 1); //网页响应 system.io.memorystream ms = new system.io.memorystream(); image.save(ms,system.drawing.imaging.imageformat.gif); response.clearcontent(); response.contenttype = "image/gif"; response.binarywrite(ms.toarray()); } finally { graphic.dispose(); image.dispose(); } }
以上所生成的为简单的验证码。接下来我从其他的博客中学习了其他形式的效果。
/* 图片画线特殊效果:贝塞尔曲线 */ graphics graph = graphics.fromimage(image); graph.clear(color.whitesmoke); point[] myarray ={ new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)), new point(random.next(150),random.next(50)) }; pen mypen = new pen(color.blue, 1); graphicspath mypath = new graphicspath(); mypath.addbeziers(myarray); graph.drawpath(mypen, mypath);
验证码字符颜色变换效果:实现该效果,我们首先来定义一个颜色集合,然后通过for循环使其随机改变字体颜色则可。
#region 定义颜色数组 color[] colors = { color.blue, color.green, color.red, color.gold, color.black, color.chocolate, color.orange, color.purple }; public color[] colors { get { return colors; } set { colors = value; } } #endregion brush brush; int colornum; for(int i=0; i { colornum = random.next(colors.length - 1); brush = new system.drawing.solidbrush(colors[cindex]); //利用drawstring函数进行颜色填充就可以了。 }
同样的原理我们也可以定义一个字体的数组来进行验证码字体切换。代码和颜色的类似,这里就不加以累赘。
接下来看看如何使得验证码的字体进行扭曲。
private const double pi = 3.1415926535897932384626433832795; private const double pi2 = 6.283185307179586476925286766559; /// /// 波形滤镜效果函数 /// /// /// /// /// /// public system.drawing.bitmap twistimage(bitmap srcbmp, double dmultvalue, double dphase) { system.drawing.bitmap destbmp = new bitmap(srcbmp.width,srcbmp.height); system.drawing.graphics graph = system.drawing.graphics.fromimage(destbmp); //填充背景图为白色 graph.fillrectangle(new solidbrush(system.drawing.color.white), 0, 0, destbmp.width, destbmp.height); graph.dispose(); double dbaselen = (double)destbmp.width; for (int i = 0; i < destbmp.width; i++) { for (int j = 0; j < destbmp.height; j++) { double dx = 0; dx = (pi2 * (double)j) / dbaselen; dx += dphase; double dy = math.sin(dx); int noldx = 0, noldy = 0; noldx = i + (int)(dy * dmultvalue); noldy = j + (int)(dy * dmultvalue); system.drawing.color color = srcbmp.getpixel(i, j); if (noldx >= 0 && noldx < destbmp.width && noldy >= 0 && noldy < destbmp.height) destbmp.setpixel(noldx, noldy, color); } } return destbmp; }
上面代码是参考了这段代码进行的学习<c#.net 好用的验证码代码 汉字-变色-扭曲-波动 >,代码如下
using system; using system.data; using system.configuration; using system.collections; using system.drawing; using system.web; using system.web.security; using system.web.ui; using system.web.ui.webcontrols; using system.web.ui.webcontrols.webparts; using system.web.ui.htmlcontrols; public partial class study_checkcode2 : system.web.ui.page { protected void page_load(object sender, eventargs e) { string code = createverifycode(); //取随机码 createimageonpage(code, this.context); // 输出图片 response.cookies.add(new httpcookie("checkcode", code.toupper()));// 使用cookies取验证码的值 } #region 验证码长度(默认4个验证码的长度) int length = 4; public int length { get { return length; } set { length = value; } } #endregion #region 验证码字体大小(为了显示扭曲效果,默认40像素,可以自行修改) int fontsize = 40; public int fontsize { get { return fontsize; } set { fontsize = value; } } #endregion #region 边框补(默认1像素) int padding = 2; public int padding { get { return padding; } set { padding = value; } } #endregion #region 是否输出燥点(默认不输出) bool chaos = true; public bool chaos { get { return chaos; } set { chaos = value; } } #endregion #region 输出燥点的颜色(默认灰色) color chaoscolor = color.lightgray; public color chaoscolor { get { return chaoscolor; } set { chaoscolor = value; } } #endregion #region 自定义背景色(默认白色) color backgroundcolor = color.white; public color backgroundcolor { get { return backgroundcolor; } set { backgroundcolor = value; } } #endregion #region 自定义随机颜色数组 color[] colors = { color.black, color.red, color.darkblue, color.green, color.orange, color.brown, color.darkcyan, color.purple }; public color[] colors { get { return colors; } set { colors = value; } } #endregion #region 自定义字体数组 string[] fonts = { "arial", "georgia" }; public string[] fonts { get { return fonts; } set { fonts = value; } } #endregion #region 自定义随机码字符串序列(使用逗号分隔) //string codeserial = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z"; string codeserial = "阿,保,持,的,法,规,和,东,三,省,问,我,惹,你,诶,没,改,变,揍,屁,股,吧"; public string codeserial { get { return codeserial; } set { codeserial = value; } } #endregion #region 产生波形滤镜效果 private const double pi = 3.1415926535897932384626433832795; private const double pi2 = 6.283185307179586476925286766559; /// <summary> /// 正弦曲线wave扭曲图片(edit by 51aspx.com) /// </summary> /// <param name="srcbmp">图片路径</param> /// <param name="bxdir">如果扭曲则选择为true</param> /// <param name="dmultvalue">波形的幅度倍数,越大扭曲的程度越高,一般为3</param> /// <param name="dphase">波形的起始相位,取值区间[0-2*pi)</param> /// <returns></returns> public system.drawing.bitmap twistimage(bitmap srcbmp, bool bxdir, double dmultvalue, double dphase) { system.drawing.bitmap destbmp = new bitmap(srcbmp.width, srcbmp.height); // 将位图背景填充为白色 system.drawing.graphics graph = system.drawing.graphics.fromimage(destbmp); graph.fillrectangle(new solidbrush(system.drawing.color.white), 0, 0, destbmp.width, destbmp.height); graph.dispose(); double dbaseaxislen = bxdir ? (double)destbmp.height : (double)destbmp.width; for (int i = 0; i < destbmp.width; i++) { for (int j = 0; j < destbmp.height; j++) { double dx = 0; dx = bxdir ? (pi2 * (double)j) / dbaseaxislen : (pi2 * (double)i) / dbaseaxislen; dx += dphase; double dy = math.sin(dx); // 取得当前点的颜色 int noldx = 0, noldy = 0; noldx = bxdir ? i + (int)(dy * dmultvalue) : i; noldy = bxdir ? j : j + (int)(dy * dmultvalue); system.drawing.color color = srcbmp.getpixel(i, j); if (noldx >= 0 && noldx < destbmp.width && noldy >= 0 && noldy < destbmp.height) { destbmp.setpixel(noldx, noldy, color); } } } return destbmp; } #endregion #region 生成校验码图片 public bitmap createimagecode(string code) { int fsize = fontsize; int fwidth = fsize + padding; int imagewidth = (int)(code.length * fwidth) + 30 + padding * 2; int imageheight = fsize * 2 + padding; system.drawing.bitmap image = new system.drawing.bitmap(imagewidth, imageheight); graphics g = graphics.fromimage(image); g.clear(backgroundcolor); random rand = new random(); //给背景添加随机生成的燥点 if (this.chaos) { pen pen = new pen(chaoscolor, 0); int c = length * 10; for (int i = 0; i < c; i++) { int x = rand.next(image.width); int y = rand.next(image.height); g.drawrectangle(pen, x, y, 1, 1); } } int left = 0, top = 0, top1 = 1, top2 = 1; int n1 = (imageheight - fontsize - padding * 2); int n2 = n1 / 4; top1 = n2; top2 = n2 * 2; font f; brush b; int cindex, findex; //随机字体和颜色的验证码字符 for (int i = 0; i < code.length; i++) { cindex = rand.next(colors.length - 1); findex = rand.next(fonts.length - 1); f = new system.drawing.font(fonts[findex], fsize, system.drawing.fontstyle.bold); b = new system.drawing.solidbrush(colors[cindex]); if (i % 2 == 1) { top = top2; } else { top = top1; } left = i * fwidth; g.drawstring(code.substring(i, 1), f, b, left, top); } //画一个边框 边框颜色为color.gainsboro g.drawrectangle(new pen(color.gainsboro, 0), 0, 0, image.width - 1, image.height - 1); g.dispose(); //产生波形(add by 51aspx.com) image = twistimage(image, true, 8, 4); return image; } #endregion #region 将创建好的图片输出到页面 public void createimageonpage(string code, httpcontext context) { system.io.memorystream ms = new system.io.memorystream(); bitmap image = this.createimagecode(code); image.save(ms, system.drawing.imaging.imageformat.jpeg); context.response.clearcontent(); context.response.contenttype = "image/jpeg"; context.response.binarywrite(ms.getbuffer()); ms.close(); ms = null; image.dispose(); image = null; } #endregion #region 生成随机字符码 public string createverifycode(int codelen) { if (codelen == 0) { codelen = length; } string[] arr = codeserial.split(','); string code = ""; int randvalue = -1; random rand = new random(unchecked((int)datetime.now.ticks)); for (int i = 0; i < codelen; i++) { randvalue = rand.next(0, arr.length - 1); code += arr[randvalue]; } return code; } public string createverifycode() { return createverifycode(0); } #endregion }
一年一度的抢票热潮又开始了,希望大家都能顺利买到回家的火车篇,回家过年,突然感觉有点年味了,一年又一年,时间都去哪了,小小的感慨一下……
言归正传,这就是为大家分享的c#验证码程序,和12306验证码差多了,不过也是小编的学习收获吧!大家也可以结合下面这两篇文章进行学习:
《12306动态验证码启发之asp.net实现动态gif验证码(附源码)》
希望本文所述对大家学习验证码技术有所帮助。